JP6072655B2 - Sensor terminal position estimation method, estimation apparatus, and estimation program - Google Patents

Description

  The present invention relates to a sensor terminal position estimation method, an estimation apparatus, and an estimation program. More specifically, the present invention relates to a technique for estimating the position of sensor terminals constituting a wireless sensor network.

  A wireless sensor network has multiple wireless sensor terminals installed so that multiple sensor terminals can communicate with each other to build a wireless network, and the sensor information collected by each sensor terminal It has a function to transmit and is expected to be applied to medical care, welfare, crime prevention, disaster prevention, environmental measurement, etc. (Patent Document 1, Patent Document 2).

  Various application examples and application examples of wireless sensor networks are conceivable. For example, when wireless sensor networks are used in fields such as state monitoring of various facilities and structures and temperature distribution measurement on farms, etc. In order to associate the target equipment or field with the installation sensor, it is necessary to know the position information of the installation sensor.

  Conventional techniques for measuring the position of a wireless terminal device constituting a wireless network include a plurality of positioning means for each of a plurality of wireless terminal devices to know the current position of the terminal, and a wireless terminal device adjacent to the terminal. And a means for correcting and supplementing the positioning result of the positioning means of the terminal itself using the positioning result of the positioning means (Patent Document 3).

Special table 2005-526416 JP 2008-78963 A JP 2006-343161 A

  However, in the position measurement method of the wireless terminal device disclosed in Patent Document 3, it is necessary that each wireless terminal device has positioning means such as GPS (abbreviation of Global Positioning System). If the reception state is not good, it is necessary to have a second positioning means for switching the positioning method and measuring the position using the position identification information (position ID), and the position ID distribution base for transmitting the position ID It is necessary to install a station, the structure of the wireless terminal device is complicated and the cost is increased, and further, the cost for installing the position ID distribution base station is required, and the cost of constructing the wireless network is further increased. It will rise. For this reason, it is difficult to say that the position measuring method of the wireless terminal device of Patent Document 3 is highly versatile. Further, since GPS generally generates an error of about 10 m, it is difficult to say that the accuracy of position measurement is high when GPS is used.

  Accordingly, an object of the present invention is to provide a sensor terminal position estimation method, an estimation apparatus, and an estimation program capable of accurately estimating the position of a sensor terminal constituting a wireless sensor network with a simple apparatus configuration. .

  In order to achieve this object, a sensor terminal position estimation method according to claim 1 is a wireless sensor network including a plurality of sensor terminals having known positions and a coordinator. A method for estimating a position, in which a counter value of a clock unit of a sensor terminal whose position is known and a sensor terminal whose position is unknown is reset, and a sound wave is transmitted at the position of the sensor terminal whose position is unknown And a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the sound wave input to the coordinator at predetermined time intervals. A sensor terminal whose position is known and a sensor terminal whose position is unknown in response to an input of a counter value request signal transmitted a plurality of times The counter value is corrected to the actual time using the step of transmitting a plurality of counter values to the coordinator, the difference between the counter values transmitted at these predetermined time intervals, and the predetermined time interval. A counter error which is an index is calculated for each sensor terminal, and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown are counters. Propagation of sound in the difference between the step corrected by error and the counter value at the time of corrected sound wave input of the sensor terminal whose position is known and the counter value at the time of corrected sound wave input of the sensor terminal whose position is unknown The step of calculating the distance between the sensor terminal whose position is known by multiplying the speed and the sensor terminal whose position is unknown, and a plurality of positions are known Certain sensor terminal and position so that a step of position using the distance between the sensor terminal is unknown is estimated the position of the sensor terminal is unknown.

  The method for estimating the position of a sensor terminal according to claim 2 is a method for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. The counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset in response to the input of the reset request signal, and the position of the sensor terminal whose position is unknown A step in which sound waves are transmitted, a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known in response to the sound wave input and a sensor terminal whose position is unknown to the coordinator, and reset Sensor end whose position is known in response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the request signal The counter value is corrected to the actual time using the step in which the counter value is transmitted from the sensor terminal whose position is unknown to the coordinator, the counter value in response to the counter value request signal, and a predetermined time interval. A step in which a counter error, which is an index for performing the calculation, is calculated for each sensor terminal, and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown The difference between the step in which each is corrected by the counter error and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is known and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is unknown A step of calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the sound propagation speed; Position using the distance between the sensor terminal and position the plurality of locations are known and the sensor terminal is unknown so that a step of the position of the sensor terminal is unknown is estimated.

  The method for estimating the position of a sensor terminal according to claim 3 is a method for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. The initial counter value is transmitted to the coordinator from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the input of the counter value request signal, and the transmission of the counter value request signal A second counter value is transmitted to the coordinator from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the input of the counter value request signal transmitted at a predetermined time interval; The step of transmitting sound waves at the position of the sensor terminal whose position is unknown, and the position is known in response to the input of sound waves A counter value using a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal and the sensor terminal whose position is unknown to the coordinator, a difference between the second counter value and the initial counter value, and a predetermined time interval The step of calculating a counter error, which is an index for correcting the actual time for each sensor terminal, and the difference value and position between the counter value at the time of sound wave input of the sensor terminal whose position is known and the initial counter value are Each of the difference value between the counter value at the time of sound wave input of the unknown sensor terminal and the initial counter value is corrected by the counter error, and the corrected difference value and the position of the sensor terminal whose position is known are unknown. A sensor terminal whose position is known by multiplying the difference from the corrected difference value of a certain sensor terminal by the propagation speed of sound and a sensor whose position is unknown The position of the sensor terminal whose position is unknown is estimated using the step of calculating the distance between the terminal and the distance between the sensor terminal whose position is known and the position of the sensor terminal whose position is unknown Step.

  The method for estimating the position of a sensor terminal according to claim 4 is a method for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. The counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset, and the step of transmitting sound waves at the position of the sensor terminal whose position is known; The counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known in response to the sound wave input and the sensor terminal whose position is unknown to the coordinator, and is transmitted a plurality of times at predetermined time intervals. A plurality of counter values from a sensor terminal whose position is known and a sensor terminal whose position is unknown in response to the input of the counter value request signal A counter error which is an index for correcting the counter value to the actual time using the step transmitted to the coordinator, the difference between the counter values transmitted at these predetermined time intervals, and the predetermined time interval A step calculated for each sensor terminal, and a counter value at the time of sound wave input of the sensor terminal whose position is known and a counter value at the time of sound wave input of the sensor terminal whose position is unknown are each corrected by a counter error. And the difference between the corrected sound value of the sensor terminal whose position is unknown and the corrected sound value of the sensor terminal whose position is known is multiplied by the sound propagation speed A step of calculating a distance between a sensor terminal having a known position and a sensor terminal having a unknown position, and a position of a sensor terminal having a plurality of known positions There has been such a step the position of the sensor terminal location is unknown by using the distance between the sensor terminal is unknown is estimated.

  The method for estimating the position of a sensor terminal according to claim 5 is a method for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. The counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset in response to the input of the reset request signal, and the position of the sensor terminal whose position is known A step in which sound waves are transmitted, a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known in response to the sound wave input and a sensor terminal whose position is unknown to the coordinator, and reset Sensor end whose position is known in response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the request signal The counter value is corrected to the actual time using the step in which the counter value is transmitted from the sensor terminal whose position is unknown to the coordinator, the counter value in response to the counter value request signal, and a predetermined time interval. A step in which a counter error, which is an index for performing the calculation, is calculated for each sensor terminal, and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown The difference between the step in which each is corrected by the counter error and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is unknown and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is known A step of calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the sound propagation speed; Position using the distance between the sensor terminal and position the plurality of locations are known and the sensor terminal is unknown so that a step of the position of the sensor terminal is unknown is estimated.

  The method for estimating the position of a sensor terminal according to claim 6 is a method for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. The initial counter value is transmitted to the coordinator from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the input of the counter value request signal, and the transmission of the counter value request signal A second counter value is transmitted to the coordinator from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the input of the counter value request signal transmitted at a predetermined time interval; A step in which a sound wave is transmitted at the position of the sensor terminal whose position is known, and the position is known in response to the input of the sound wave. A counter value using a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal and the sensor terminal whose position is unknown to the coordinator, a difference between the second counter value and the initial counter value, and a predetermined time interval The step of calculating a counter error, which is an index for correcting the actual time for each sensor terminal, and the difference value and position between the counter value at the time of sound wave input of the sensor terminal whose position is known and the initial counter value are Each of the difference value between the counter value at the time of sound wave input of the unknown sensor terminal and the initial counter value is corrected by the counter error, and the corrected difference value and the position of the sensor terminal whose position is unknown are known. A sensor terminal whose position is known by multiplying the difference from the corrected difference value of a certain sensor terminal by the propagation speed of sound and a sensor whose position is unknown The position of the sensor terminal whose position is unknown is estimated using the step of calculating the distance between the terminal and the distance between the sensor terminal whose position is known and the position of the sensor terminal whose position is unknown Step.

  The apparatus for estimating a position of a sensor terminal according to claim 8 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the sound wave transmitted at the position of the sensor terminal whose position is unknown after the counter value of the clock part of the sensor terminal whose position is unknown and the sensor terminal whose position is unknown is reset. Means for receiving a counter value at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator, and a counter value transmitted a plurality of times at predetermined time intervals Coordinator sent from the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to the input of the request signal Therefore, it is an index for correcting the counter value to the actual time by using the means for receiving the received counter values and the difference between the counter values transmitted at a predetermined time interval and the predetermined time interval. A means for calculating a certain counter error for each sensor terminal and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown are corrected by the counter error. And the difference between the counter value at the time of corrected sound wave input of the sensor terminal whose position is known and the counter value at the time of corrected sound wave input of the sensor terminal whose position is unknown are multiplied by the propagation speed of sound. Means for calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown, and a sensor terminal whose position is unknown and a plurality of sensor terminals whose positions are unknown. Position using the distance between the support terminal is to have a means for estimating the position of the sensor terminal is unknown.

  The apparatus for estimating the position of a sensor terminal according to claim 9 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. At the position of the sensor terminal whose position is unknown after the counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset in response to the input of the reset request signal Means for receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known in response to an input of a transmitted sound wave and received from a sensor terminal whose position is unknown and received by a coordinator; and a reset request signal A sensor terminal whose position is known in response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of The counter value is sent to the actual time using a means for receiving the counter value transmitted from the sensor terminal whose unknown is received and received by the coordinator, the counter value in response to the counter value request signal, and a predetermined time interval. Means for calculating for each sensor terminal a counter error, which is an index for correcting to, a counter value at the time of sound wave input of a sensor terminal whose position is known, and a counter value at the time of sound wave input of a sensor terminal whose position is unknown And a difference between the counter value at the time of the corrected sound wave input of the sensor terminal whose position is known and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is unknown. Means for calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the sound propagation speed, and a plurality of positions Position using the distance between the sensor terminal is unknown is to have a means for estimating the position of the sensor terminal is unknown is the sensor terminals and the position is known.

  The apparatus for estimating a position of a sensor terminal according to claim 10 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. A means for receiving an input of an initial counter value transmitted from a sensor terminal whose position is known in response to an input of a counter value request signal and a sensor terminal whose position is unknown and received by a coordinator, and a counter value request The second counter received from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the signal A means for receiving a value input and a response to the input of a sound wave transmitted at the position of the sensor terminal whose position is unknown. A means for receiving an input of a counter value at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator, and a second counter value and an initial counter value Means for calculating for each sensor terminal a counter error which is an index for correcting the counter value to the actual time using the difference and a predetermined time interval; and a counter value at the time of sound wave input of the sensor terminal whose position is known Means for correcting each difference value between the counter value and the initial counter value at the time of sound wave input of the sensor terminal whose difference value and position from the initial counter value are unknown, and correction of the sensor terminal whose position is known Sensor terminal whose position is known by multiplying the difference between the measured difference value and the corrected difference value of the sensor terminal whose position is unknown by multiplying the sound propagation speed A sensor terminal whose position is unknown using means for calculating a distance between a sensor terminal whose position is unknown and a distance between a sensor terminal whose position is unknown and a sensor terminal whose position is unknown Means for estimating the position of the.

  The apparatus for estimating a position of a sensor terminal according to claim 11 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the sound wave transmitted at the position of the sensor terminal whose position is known after the counter value of the clock part of the sensor terminal whose position is unknown and the sensor terminal whose position is unknown is reset. Means for receiving a counter value at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator, and a counter value transmitted a plurality of times at predetermined time intervals In response to the input of the request signal, the sensor terminal whose position is known and the sensor terminal whose position is unknown are transmitted and coordinated. An index for correcting the counter value to the actual time using the means for receiving the input of the plurality of counter values received by the, the difference between the counter values transmitted at a predetermined time interval and the predetermined time interval A means for calculating a certain counter error for each sensor terminal and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown are corrected by the counter error. And the difference between the counter value at the time of the corrected sound wave input of the sensor terminal whose position is unknown and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is known is multiplied by the sound propagation speed Means for calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown, and the position of the sensor terminal whose positions are known and the position are unknown Position using the distance between the capacitors terminal is to have a means for estimating the position of the sensor terminal is unknown.

  The apparatus for estimating a position of a sensor terminal according to claim 12 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the reset request signal, the counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset and the position of the sensor terminal whose position is known is Means for receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known in response to an input of a transmitted sound wave and received from a sensor terminal whose position is unknown and received by a coordinator; and a reset request signal A sensor terminal whose position is known in response to an input of a counter value request signal transmitted at a predetermined time interval from the transmission of The counter value is actually transmitted by using the means for receiving the counter value transmitted from the sensor terminal whose position is unknown and received by the coordinator, the counter value in response to the counter value request signal, and the predetermined time interval. Means for calculating for each sensor terminal a counter error that is an index for correcting time, a counter value at the time of sound wave input of a sensor terminal whose position is known, and a counter value at the time of sound wave input of a sensor terminal whose position is unknown And the difference between the counter value at the time of the corrected sound wave input of the sensor terminal whose position is unknown and the counter value at the time of the corrected sound wave input of the sensor terminal whose position is known Means for calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown by multiplying the sound propagation speed by a plurality of Location is a sensor device and the position is known so that a means for estimating the position of the sensor terminal location is unknown by using the distance between the sensor terminal is unknown.

  The apparatus for estimating a position of a sensor terminal according to claim 13 is an apparatus for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. A means for receiving an input of an initial counter value transmitted from a sensor terminal whose position is known in response to an input of a counter value request signal and a sensor terminal whose position is unknown and received by a coordinator, and a counter value request The second counter received from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the signal A means for receiving an input of a value, and an input of a sound wave transmitted at the position of a sensor terminal whose position is known. A means for receiving an input of a counter value at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator, and a second counter value and an initial counter value Means for calculating for each sensor terminal a counter error which is an index for correcting the counter value to the actual time using the difference and a predetermined time interval; and a counter value at the time of sound wave input of the sensor terminal whose position is known Means for correcting the difference value between the counter value and the initial counter value at the time of sound wave input of the sensor terminal whose position value is unknown and the difference between the initial counter value and the initial counter value, and correction of the sensor terminal whose position is unknown Sensor terminal whose position is known by multiplying the difference between the measured difference value and the corrected difference value of the sensor terminal whose position is known by the sound propagation speed A sensor terminal whose position is unknown using means for calculating a distance between a sensor terminal whose position is unknown and a distance between a sensor terminal whose position is unknown and a sensor terminal whose position is unknown Means for estimating the position of the.

  The sensor terminal position estimation program according to claim 15 is a process for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. This is a program for causing the computer to perform transmission at the position of the sensor terminal whose position is unknown after the counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset. A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known in response to the input of a sound wave and a sensor terminal whose position is unknown and received by a coordinator, and a predetermined time interval In response to the input of the counter value request signal transmitted multiple times in the sensor terminal and the position is known The counter value is calculated using a process of receiving input of a plurality of counter values transmitted from a known sensor terminal and received by a coordinator, and a difference between the counter values transmitted at a predetermined time interval and a predetermined time interval. A process for calculating a counter error, which is an index for correcting the actual time, for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and a time of sound wave input of the sensor terminal whose position is unknown A process of correcting each of the counter values by a counter error, a counter value at the time of a corrected sound wave input of a sensor terminal whose position is known, and a counter value at the time of a sound wave input corrected by a sensor terminal whose position is unknown A process of calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the difference between the two and the sound propagation speed, and a plurality of Position is the position with the sensor terminal is known so that to perform the processing position to estimate the position of the sensor terminal is unknown by using the distance between the sensor terminal is unknown to the computer.

  A sensor terminal position estimation program according to claim 16 is a process for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the reset request signal, the counter value of the clock unit between the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset and the position is reset. Input of counter value at the time of sound wave input received from the sensor terminal whose position is known in response to the input of the sound wave transmitted at the position of the unknown sensor terminal and the sensor terminal whose position is unknown and received by the coordinator Counter value request signal transmitted at a predetermined time interval from the processing of receiving the reset request signal A process of receiving an input of a counter value transmitted from a sensor terminal whose position is known in response to an input and received from the sensor terminal whose position is unknown, and a counter value as a response to the counter value request signal; Processing for calculating for each sensor terminal a counter error, which is an index for correcting the counter value to the actual time using a predetermined time interval, and the counter value and position at the time of sound wave input of the sensor terminal whose position is known Correction of each of the counter value at the time of sound wave input of the sensor terminal whose sensor is unknown by the counter error, and the sensor terminal of which the position of the sensor terminal whose position is known is corrected and the position at the time of sound wave input unknown The position of the sensor terminal whose position is known is unknown by multiplying the difference from the counter value at the time of the corrected sound wave input by the propagation speed of the sound. The position of the sensor terminal whose position is unknown is estimated using the process of calculating the distance to the sensor terminal and the distance between the sensor terminal whose position is known and the position of the sensor terminal whose position is unknown. Processing is performed by a computer.

  The sensor terminal position estimation program according to claim 17 is a process for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. Input of the initial counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the counter value request signal. In response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the counter value request signal and the coordinator transmitted from the sensor terminal whose position is unknown and the sensor terminal whose position is unknown Processing to receive the input of the second counter value received by the A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator in response to the input of the sound wave transmitted at the position of the service terminal And a process for calculating for each sensor terminal a counter error that is an index for correcting the counter value to an actual time using a difference between the second counter value and the initial counter value and a predetermined time interval, and a position The difference value between the counter value at the time of sound wave input of the known sensor terminal and the initial counter value and the difference value between the counter value at the time of sound wave input of the sensor terminal whose position is unknown and the initial counter value are corrected by the counter error. The difference between the corrected difference value of the sensor terminal having the known position and the corrected difference value of the sensor terminal having the unknown position. A process of calculating the distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the speed, and a sensor terminal whose position is unknown and a sensor terminal whose position is unknown The computer is caused to perform a process of estimating the position of the sensor terminal whose position is unknown using the distance between them.

  A sensor terminal position estimation program according to claim 18 is a process for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. This is a program for causing the computer to perform transmission at the position of the sensor terminal whose position is known after the counter value of the clock part of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset. A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known in response to the input of a sound wave and a sensor terminal whose position is unknown and received by a coordinator, and a predetermined time interval In response to the input of the counter value request signal transmitted multiple times in the sensor terminal and the position is known The counter value is calculated using a process of receiving input of a plurality of counter values transmitted from a known sensor terminal and received by a coordinator, and a difference between the counter values transmitted at a predetermined time interval and a predetermined time interval. A process for calculating a counter error, which is an index for correcting the actual time, for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and a time of sound wave input of the sensor terminal whose position is unknown A process of correcting each of the counter values with a counter error, a counter value at the time of a corrected sound wave input of a sensor terminal whose position is unknown, and a counter value at the time of a sound wave input corrected of a sensor terminal whose position is known; A process of calculating a distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the difference between the two and the sound propagation speed, and a plurality of Position is the position with the sensor terminal is known so that to perform the processing position to estimate the position of the sensor terminal is unknown by using the distance between the sensor terminal is unknown to the computer.

  The program for estimating the position of a sensor terminal according to claim 19 is a process for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the reset request signal, the counter value of the clock unit between the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset and the position is reset. Input of counter value at the time of sound wave input received from the sensor terminal whose position is known in response to the input of the sound wave transmitted at the position of the known sensor terminal and the sensor terminal whose position is unknown and received by the coordinator Counter value request signal transmitted at a predetermined time interval from the processing of receiving the reset request signal A process of receiving an input of a counter value transmitted from a sensor terminal whose position is known in response to an input and received from the sensor terminal whose position is unknown, and a counter value as a response to the counter value request signal; Processing for calculating for each sensor terminal a counter error, which is an index for correcting the counter value to the actual time using a predetermined time interval, and the counter value and position at the time of sound wave input of the sensor terminal whose position is known Processing for correcting each of the counter value at the time of sound wave input of the sensor terminal whose sensor is unknown by a counter error, and the sensor terminal for which the position of the sensor terminal whose position is unknown is corrected and the position at the time of sound wave input is known The position of the sensor terminal whose position is known is unknown by multiplying the difference from the counter value at the time of the corrected sound wave input by the propagation speed of the sound. The position of the sensor terminal whose position is unknown is estimated using the process of calculating the distance to the sensor terminal and the distance between the sensor terminal whose position is known and the position of the sensor terminal whose position is unknown. Processing is performed by a computer.

  A sensor terminal position estimation program according to claim 20 is a process for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. Input of the initial counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the counter value request signal. In response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the counter value request signal and the coordinator transmitted from the sensor terminal whose position is unknown and the sensor terminal whose position is unknown Processing for receiving the second counter value received by the A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown and received by the coordinator in response to the input of the sound wave transmitted at the position of the service terminal And a process for calculating for each sensor terminal a counter error that is an index for correcting the counter value to an actual time using a difference between the second counter value and the initial counter value and a predetermined time interval, and a position The difference value between the counter value at the time of sound wave input of the known sensor terminal and the initial counter value and the difference value between the counter value at the time of sound wave input of the sensor terminal whose position is unknown and the initial counter value are corrected by the counter error. The difference between the corrected difference value of the sensor terminal having the unknown position and the corrected difference value of the sensor terminal having the known position. A process of calculating the distance between a sensor terminal whose position is known and a sensor terminal whose position is unknown by multiplying the speed, and a sensor terminal whose position is unknown and a sensor terminal whose position is unknown The computer is caused to perform a process of estimating the position of the sensor terminal whose position is unknown using the distance between them.

  Therefore, according to the estimation method, estimation apparatus, and estimation program of the sensor terminal position, the counter value transmitted from the sensor terminal (known terminal) whose position is known and the sensor terminal (unknown terminal) whose position is unknown are actually The counter error, which is an index for correcting the counter value to the actual time using the time interval, is calculated for each sensor terminal, and the counter value at the time of sound wave input of the known terminal and the unknown terminal is calculated using the counter error. The difference between the counter value at the time of sound wave input of the known terminal and the counter value at the time of sound wave input of the unknown terminal is the actual sound propagation time between both terminals. The distance between the two terminals is accurately calculated by multiplying the difference between the counter value at the time (after correction) and the counter value at the time of sound wave input from the unknown terminal (after correction) by the sound propagation speed. Presumed.

  The sensor terminal position estimation method according to the present invention includes a sensor terminal in which a counter value request signal is transmitted a plurality of times at predetermined time intervals, and the position is known in response to the input of the plurality of counter value request signals. A plurality of counter values are transmitted to the coordinator from the sensor terminal whose unknown is unknown, the counter error is calculated for each combination of the difference between these counter values and a predetermined time interval, and the average value or median value of these counter errors May be used as the final counter error. The sensor terminal position estimation apparatus according to the present invention transmits from a sensor terminal whose position is known and a sensor terminal whose position is unknown in response to an input of a counter value request signal transmitted a plurality of times at predetermined time intervals. In response to the input of a plurality of counter values received by the coordinator, the counter error is calculated for each combination of the difference between the counter values and a predetermined time interval, and the average value or median value of these counter errors is finally determined. It may be used as a counter error. The sensor terminal position estimation program of the present invention is transmitted from a sensor terminal whose position is known and a sensor terminal whose position is unknown in response to an input of a counter value request signal transmitted a plurality of times at predetermined time intervals. In response to the input of a plurality of counter values received by the coordinator, the counter error is calculated for each combination of the difference between the counter values and a predetermined time interval, and the average value or median value of these counter errors is finally determined. It may be used as a counter error. In these cases, a more appropriate counter error is used.

  According to the sensor terminal position estimation method, estimation apparatus, and estimation program of the present invention, the counter error is calculated and the counter value at the time of sound wave input of the known terminal and the unknown terminal is corrected using the counter error. Therefore, the distance between the two terminals can be accurately calculated by multiplying the difference between the counter value at the time of sound wave input of the known terminal (after correction) and the counter value at the time of sound wave input of the unknown terminal (after correction) by the sound propagation speed. Since it can be estimated, it is possible to improve the estimation accuracy of the position of the sensor terminal constituting the wireless sensor network. In addition, the calculation of the counter error can be performed using the counter function of the sensor terminal itself, and the position of the sensor terminal can be estimated by transmitting and receiving sound waves. Without being used, it is possible to accurately estimate the position of the sensor terminal constituting the wireless sensor network with a simple device configuration. As a result, according to the sensor terminal position estimation method, estimation apparatus, and estimation program of the present invention, it is possible to save the acquisition of the sensor terminal position information, so that the wireless sensor network construction work can be made more efficient. Is possible.

  Furthermore, the sensor terminal position estimation method, estimation apparatus, and estimation program of the present invention use an average value or median value of counter errors calculated for each combination of a difference between a plurality of counter values and a predetermined time interval. In this case, a more appropriate counter error can be used, so that it is possible to further improve the estimation accuracy of the position of the sensor terminal constituting the wireless sensor network.

It is a flowchart explaining an example of embodiment of the estimation method of the sensor terminal position of this invention. It is a functional block diagram of the estimation apparatus of a sensor terminal position implement | achieved by the said program in the case of implementing the estimation method of a sensor terminal position of an example of embodiment using the estimation method program of a sensor terminal position. It is a figure explaining the sensor network of an example of embodiment. It is a functional block diagram which shows an example of a sensor terminal (a known terminal, an unknown terminal). It is a functional block diagram which shows an example of a reference | standard terminal. It is a sequence flowchart which shows the flow of estimation of the position of the unknown terminal of an example of embodiment. It is a flowchart explaining the other example of embodiment of the estimation method of the sensor terminal position of this invention. It is a functional block diagram of the estimation apparatus of the sensor terminal position implement | achieved by the said program in the case of implementing the estimation method of the sensor terminal position of the other example of embodiment using the estimation method program of a sensor terminal position. It is a figure explaining the sensor network of other examples of an embodiment. It is a sequence flowchart which shows the flow of the estimation of the position of the unknown terminal of the other example of embodiment. It is a sequence flowchart which shows the flow of estimation of the position of the unknown terminal of other embodiment. It is a sequence flowchart which shows the flow of estimation of the position of the unknown terminal of other embodiment. It is a sequence flowchart which shows the flow of estimation of the position of the unknown terminal of other embodiment.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  FIG. 1 to FIG. 10 show examples of embodiments of the sensor terminal position estimation method, estimation apparatus, and estimation program of the present invention.

  Note that a wireless sensor network transmits sensor data collected by each sensor terminal by transmitting a plurality of sensor terminals having a wireless communication function and relaying communication between the sensor terminals. It is a network configured. The sensor terminals can transmit radio signals and autonomously transmit data between the sensor terminals by multi-hop communication. Multi-hop communication refers to communication that connects to each other without intervention of an access point.

  Specifically, it is conceivable that the wireless sensor set work is constructed by using ZigBee, which is one of short-range wireless communication standards whose main purpose is a sensor network. The ZigBee terminal has a relay function, and by repeating the relay, information can be transmitted as long as ZigBee elements can communicate with each other. Also, the specification of the basic part of ZigBee is standardized as IEEE 802.15.4.

  In order to construct a wireless sensor network using sensor terminals, a plurality of sensor terminals are installed at appropriate intervals within the reach of the radio waves transmitted from the sensor terminals with respect to the equipment, structures and areas to be monitored. The

  3 and 9 showing a wireless sensor network constructed by installing a plurality of sensor terminals, reference numerals 2A, 2B, and 2C denote sensor terminals whose positions are known (referred to as known terminals), and reference numeral 3 denotes a position. Represents a sensor terminal whose name is unknown (referred to as an unknown terminal).

  In the examples of FIGS. 3 and 9, it is assumed that there are three known terminals that are within the reach of the radio wave transmitted from the unknown terminal 3 (in other words, the radio wave transmitted from itself reaches the unknown terminal 3). As a general rule, the number of known terminals within the reach of the radio waves transmitted from the unknown terminal 3 is as follows in principle when the known terminal and the unknown terminal are on the same plane and the position of the unknown terminal on the plane is estimated. If the number is 3 or more, it may be any number (but may be 2 in some cases), and the known terminal and the unknown terminal are arranged three-dimensionally and the position of the unknown terminal is estimated including the height. In principle, any number of 4 or more may be used (however, 3 may be used in some cases).

  Further, it is not necessary that all sensor terminals other than the unknown terminal 3 are known terminals. In other words, the position of the unknown terminal 3 can be estimated if there are more than the known terminals satisfying the predetermined condition described in detail in the following description. Therefore, in addition to the unknown terminal 3, the sensor terminal whose position is unknown There is no problem.

  Known terminals 2A, 2B, 2C (hereinafter referred to as “known terminal 2” when there is no need to distinguish each known terminal or when all known terminals are indicated), as shown in FIG. The sensor part 2a, the clock part 2b, the transmission / reception part 2c, the control part 2d, the sound wave receiving part 2e, and the power supply part 2f are provided.

  The sensor unit 2a performs measurement by exhibiting a sensor function according to the purpose as a sensor terminal installed for various purposes, and outputs measurement data acquired by measurement to the control unit 2d. For example, the sensor includes a sensor that can measure temperature, vibration, sound, brightness, and the like.

  The clock unit 2b measures time (in other words, accumulates) at a predetermined interval (in other words, counter speed or time increment) such as 1 millisecond or 100 microseconds. Is extracted as a counter value from the clock unit 2b.

  The transmission / reception unit 2c is a circuit that transmits and receives a radio signal via an antenna. Specifically, for example, measurement data acquired by the sensor unit 2a is input via the control unit 2d, the measurement data is converted into a radio signal, and wirelessly transmitted to the outside via an antenna. Also, a radio signal received by the antenna is input, the radio signal is converted into digital information, and is output to the control unit 2d as received data.

  The control unit 2d controls the operation of the known terminal 2, and is configured by an integrated circuit, for example.

  The sound wave receiving unit 2e receives the sound wave and outputs the received sound wave signal to the control unit 2d as a sound wave reception signal. When the sensor unit 2a of the known terminal 2 is a sound sensor (in other words, when the sensor function corresponding to the purpose of the known terminal 2 as a sensor terminal is sound measurement), the known terminal 2 has the sensor function. It is sufficient to use a sound wave receiving function (a sound sensor as the sensor unit 2a) provided as the above, and it is not necessary to provide a further sound wave receiving function corresponding to the present invention.

  The power supply unit 2 f is a power supply that enables the known terminal 2 such as a dry battery or a solar cell to be driven independently, or a part that receives power supply from an external power supply, and supplies power to the above-described units 2 a to 2 e. .

  As shown in FIG. 4, the unknown terminal 3 has the same configuration as the known terminal 2, that is, the sensor unit 3a, the clock unit 3b, the transmission / reception unit 3c, the control unit 3d, as shown in FIG. A sound wave receiving unit 3e and a power supply unit 3f are provided.

  In addition, a coordinator 1 is provided that receives at least radio signals from each known terminal 2 and unknown terminal 3 and converts the radio signals into digital information and outputs the digital information to an external device. The coordinator 1 is connected to a processing device (specifically, for example, a computer) having a data signal input / output function and an arithmetic function, and outputs digital information using the processing device as the external device described above.

  The coordinator 1 corresponds to a ZigBee Coordinator when associated with the ZigBee configuration, and is a terminal that exists in the network and controls the network. The coordinator 1 corresponds to FFD (abbreviation of Full-Function Device) as a PAN coordinator in IEEE802.15.4, which is a protocol for WPAN (abbreviation of wireless personal area network). Therefore, the coordinator 1 is an example of the configuration of an FFD as a ZigBee Coordinator or a PAN coordinator. Specifically, at least an antenna for transmitting and receiving a radio signal and a radio signal received by the antenna are input. And a transmission / reception circuit that converts the radio signal into digital information and outputs it as received data, and converts data (digital information) input from the outside into a radio signal and outputs the radio signal to the antenna.

  Moreover, in this embodiment, as shown in FIG. 5, the reference | standard terminal which equips the transmission / reception part 4c (an antenna is included), the control part 4d, and the power supply part 4f as the thing similar to the known terminal 2, and is equipped with the sound wave transmission part 4e. 4 is used.

  In the following, a case where the position of the unknown terminal 3 is estimated in the wireless sensor network shown in FIGS. 3 and 9 configured using the above-described devices will be described as an example.

  As a method of estimating the position of the unknown terminal 3 in the wireless sensor network, (1) a method of generating a sound by installing the reference terminal 4 at the position of the unknown terminal 3 (FIG. 3), and (2) of the known terminal 2 There are two methods, that is, a method of generating a sound by installing the reference terminal 4 at a position (FIG. 9).

(1) A method of generating sound by installing the reference terminal 4 at the position of the unknown terminal 3 First, a method of estimating the position of the unknown terminal 3 by installing the reference terminal 4 at the position of the unknown terminal 3 and generating sound. explain.

  The method of estimating the position of the sensor terminal in this method is a method of estimating the position of the unknown terminal 3 in a wireless sensor network including a plurality of known terminals 2 and a coordinator 1 as shown in FIGS. Yes, a step (S1) in which the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 are reset, a step in which a sound wave is transmitted at the position of the unknown terminal 3 (S5), and a sound wave input In response, a counter value at the time of sound wave input from the known terminal 2 and the unknown terminal 3 is transmitted to the coordinator 1 (S6), and a counter value request signal transmitted a plurality of times at a predetermined time interval t [seconds]. A plurality of counter values are transmitted from the known terminal 2 and the unknown terminal 3 to the coordinator 1 in response to the input (S7-S10), and these predetermined values A step of calculating a counter error, which is an index for correcting the counter value to the actual time using the difference between the counter values transmitted at the interval and the predetermined time interval t (S11) ), The counter value when the sound wave is input from the known terminal 2 and the counter value when the sound wave is input from the unknown terminal 3 are corrected by the counter error (S12), and the corrected sound wave is input from the known terminal 2 The distance L between the known terminal 2 and the unknown terminal 3 is calculated by multiplying the difference between the counter value of the unknown terminal 3 and the counter value at the time of the corrected sound wave input of the unknown terminal 3 by the sound propagation speed (S13). And a step of estimating the position of the unknown terminal 3 using the distance L between the plurality of known terminals 2 and the unknown terminal 3 (S14).

  The sensor terminal position estimation method can be realized as a sensor terminal position estimation apparatus. The sensor terminal position estimation apparatus 10 according to the present embodiment is an apparatus that estimates the position of an unknown terminal 3 in a wireless sensor network including a plurality of known terminals 2 and a coordinator 1. 3 and the counter values of the clock units 2b and 3b are reset and transmitted from the known terminal 2 and the unknown terminal 3 in response to the input of the sound wave transmitted at the position of the unknown terminal 3 and received by the coordinator 1 In response to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval t [seconds], the coordinator 1 receives the counter value at the time of sound wave input and is transmitted from the known terminal 2 and the unknown terminal 3 in response to the input of the counter value request signal. A data input receiving unit 11a as a means for receiving a plurality of received counter values, and counter values transmitted at predetermined time intervals A counter error calculation unit 11b as a means for calculating a counter error for each of the terminals 2 and 3 as an index for correcting the counter value to an actual time using the difference and a predetermined time interval t; A counter value correcting unit 11c as means for correcting each of the counter value at the time of sound wave input and the counter value at the time of sound wave input of the unknown terminal 3 by a counter error; and the counter value at the time of sound wave input corrected by the known terminal 2; A distance calculation unit 11d as means for calculating the distance L between the known terminal 2 and the unknown terminal 3 by multiplying the difference between the corrected value of the unknown terminal 3 and the counter value at the time of sound wave input by the propagation speed of sound; A position estimation unit 11e serving as means for estimating the position of the unknown terminal 3 using the distance L between the plurality of known terminals 2 and the unknown terminal 3;

  The sensor terminal position estimation method and sensor terminal position estimation apparatus can also be realized by executing a sensor terminal position estimation program on a computer. Here, a case will be described in which the sensor terminal position estimation apparatus is realized and the sensor terminal position estimation method is executed by executing a sensor terminal position estimation program on a computer.

  FIG. 2 shows an overall configuration of a computer 10 (which is also a sensor terminal position estimation apparatus 10 in the present embodiment) for executing the sensor terminal position estimation program 17. The computer 10 (sensor terminal position estimating apparatus 10) includes a control unit 11, a storage unit 12, an input unit 13, a display unit 14, and a memory 15, and is connected to each other by a signal line such as a bus.

  The control unit 11 performs an operation related to the control of the entire computer 10 and the estimation of the sensor terminal position by the sensor terminal position estimation program 17 stored in the storage unit 12, and for example, a CPU (Central Processing Unit). is there.

  The storage unit 12 is a device that can store at least data and programs, and is, for example, a hard disk.

  The memory 15 serves as a memory space that is a work area when the control unit 11 executes various controls and operations, and is, for example, a RAM (abbreviation of Random Access Memory).

  The input unit 13 is an interface for giving at least an operator's command to the control unit 11, and is, for example, a keyboard.

  The display unit 14 performs drawing / display of characters, graphics, and the like under the control of the control unit 11 and is, for example, a display.

  Then, the control unit 11 of the computer 10 (which is also the sensor terminal position estimation device 10 in this embodiment) executes a sensor terminal position estimation program 17 so that a plurality of known terminals 2 and the coordinator 1 are connected. In order to estimate the position of the unknown terminal 3 in the wireless sensor network including the information, the counter values of the clock units 2b and 3b between the known terminal 2 and the unknown terminal 3 are reset and transmitted at the position of the unknown terminal 3. In response to the input of the sound wave, a process of receiving the input of the counter value at the time of sound wave input transmitted from the known terminal 2 and the unknown terminal 3 and received by the coordinator 1 is performed, and a plurality of times are received at a predetermined time interval t [seconds]. Sent from the known terminal 2 and unknown terminal 3 in response to the input of the counter value request signal transmitted once, and received by the coordinator 1. The counter value is set to the actual time using the data input receiving unit 11a that performs processing for receiving the input of the plurality of counter values, the difference between the counter values transmitted at a predetermined time interval, and the predetermined time interval t. A counter error calculation unit 11b that performs processing for calculating a counter error, which is an index for correction, for each of the terminals 2 and 3, a counter value at the time of sound wave input of the known terminal 2, and a counter value at the time of sound wave input of the unknown terminal 3 And a counter value correction unit 11c that performs a process of correcting each of the above-described counter errors, and a difference between a counter value at the time of corrected sound wave input of the known terminal 2 and a counter value of the unknown terminal 3 at the time of sound wave input corrected. A distance calculation unit 11d that performs a process of calculating the distance L between the known terminal 2 and the unknown terminal 3 by multiplying the propagation speeds of the two and the distance L between the plurality of known terminals 2 and the unknown terminal 3 A position estimation unit 11e to perform the process of estimating the position of the unknown terminal 3 is formed.

  Further, the coordinator 1 is electrically connected to the computer 10 (sensor terminal position estimating device 10) so that signals such as data and control commands can be transmitted and received (that is, input / output).

  Further, the position of each known terminal 2 (specifically, the position coordinates with an arbitrary point as the origin) is recorded in the known terminal position data file in association with the terminal ID, and stored in the storage unit 12 in advance. .

  In the method (1), the reference terminal 4 is installed at the position of the unknown terminal 3. Since the position of the reference terminal 4 is estimated in the following processing, the position as close as possible to the unknown terminal 3 so that the position of the reference terminal 4 matches the position of the unknown terminal 3 whose position is unknown. It is preferable that the reference terminal 4 is installed.

  First, the reference terminal 4 wirelessly transmits (broadcasts) a radio signal (referred to as a reset request signal) including a command for resetting the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 by the transmission / reception unit 4c (broadcast). S1).

  Each known terminal 2 and unknown terminal 3 that have received the reset request signal via the transmission / reception units 2c and 3c reset the counter values of the clock units 2b and 3b, and then send the reset signal to the reference terminal by the transmission / reception units 2c and 3c. 4 is transmitted wirelessly (S2).

  As a result, the counters of each known terminal 2 and unknown terminal 3 that have received the reset request signal are synchronized (in other words, the counter values are aligned).

  Subsequently, the reference terminal 4 that has received the reset signal from each known terminal 2 and unknown terminal 3 via the transmission / reception unit 4c includes a radio signal including a command for the known terminal 2 and unknown terminal 3 to prepare a standby state for sound input. (Referred to as a standby request signal) is wirelessly transmitted (broadcasted) by the transmission / reception unit 4c (S3).

  When each of the known terminal 2 and the unknown terminal 3 that have received the standby request signal via the transmission / reception units 2c and 3c exceeds the predetermined threshold value (referred to as a sound threshold value) input to the sound wave reception units 2e and 3e. After preparing to transmit the counter value, the standby signal is wirelessly transmitted to the reference terminal 4 by the transmission / reception units 2c and 3c (S4).

  As a result, each of the known terminal 2 and the unknown terminal 3 that have received the standby request signal is in a state in which it is ready to transmit a counter value when the input to the sound wave receiving units 2e and 3e exceeds the sound threshold. (In other words, the volume of the input sound exceeds the sound threshold value), a waiting state is entered.

  Note that the sound threshold is not limited to a specific value, and is appropriately set in consideration of the location where the wireless network is constructed, the surrounding environment, and the like. That is, when a constant sound (background sound) is emitted continuously or intermittently at or around the place where the wireless network is constructed, the input to the sound wave receiving units 2e and 3e does not exceed the background sound. The sound threshold is set to such a value.

  Here, each known terminal 2 and unknown terminal 3 may be in a trigger waiting state, which may be autonomously performed by each known terminal 2 and unknown terminal 3. That is, each known terminal 2 and unknown terminal 3 that have received the reset request signal wirelessly transmitted in the process of S1 resets the counter values of the clock units 2b and 3b, and then further adjusts the trigger wait state. Also good. In this case, the wireless transmission of the reset signal by each known terminal 2 and unknown terminal 3 as in the process of S2 is not performed, and the standby request signal is also wirelessly transmitted by the reference terminal 4 as in the process of S3. Instead, each known terminal 2 and unknown terminal 3 resets the counter value and prepares a trigger wait state, and then wirelessly transmits a standby signal.

  Next, the reference terminal 4 that has received the standby signal from each known terminal 2 and unknown terminal 3 via the transmission / reception unit 4c transmits a sound wave (referred to as a reference sound) by the sound wave transmission unit 4e (S5).

  The reference sound transmitted from the reference terminal 4 can be received as a sound exceeding the sound threshold at the positions of the known terminals 2 and unknown terminals 3, for example, the sound wave receiving units 2e and 3e of the known terminals 2 and unknown terminals 3. Is not limited to a specific sound as long as the sound is recognizable sound quality (frequency) and adjusted to an appropriate level in relation to the sound threshold.

  Note that the reference sound transmitted from the reference terminal 4 is preferably an audible sound range because there is a restriction that the propagation distance from the ultrasonic oscillator is as short as about 1.5 m if it is an ultrasonic wave. The reference sound transmitted from the reference terminal 4 is also a short pulse-like sound whose rise and convergence are abrupt in order to prevent erroneous recognition that a sound exceeding the sound threshold has been input a plurality of times. It is preferable that

  Then, when the input to the sound wave receiving units 2e and 3e exceeds the sound threshold, each known terminal 2 and unknown terminal 3 are referred to as a counter value at that time (that is, a counter value at the time of sound wave input: a counter value at a trigger time). ) Is wirelessly transmitted to the coordinator 1 by the transmission / reception units 2c and 3c together with the terminal ID (S6).

Coordinator 1, each known terminal 2A, 2B, the terminal ID and the trigger when the counter value C _2A transmitted from 2C, C _2B, C _2C and receives the terminal ID and the trigger when the counter value C ₃ transmitted from the unknown terminal 3 At the same time, the terminal ID and trigger counter values C _2A , C _2B , C _2C , and C ₃ are output to the sensor terminal position estimating apparatus 10.

Then, the data input receiving unit 11a of the control unit 11 of the sensor terminal position estimating apparatus 10 includes the trigger time counter values C _2A , C _2B , C _{2C of the} known terminals 2A, 2B, _2C and the unknown terminal 3 trigger time counter. The value C ₃ is stored in the memory 15 in association with the terminal ID.

Here, using the known terminal 2A obtained by the procedure of S1 through the above to S6, 2B, the trigger when the counter value C _2A of 2C, C _2B, and a trigger when the counter value C ₃ of the C _2C and the unknown terminal 3 Although the position of the unknown terminal 3 can be estimated, since the trigger counter value C extracted from each known terminal 2 and the clock units 2b and 3b of the unknown terminal 3 is used, the position estimation accuracy of the unknown terminal 3 is It is affected by whether the counters of the known terminal 2 and the unknown terminal 3 are synchronized. Here, the counter values extracted from the clock units 2b and 3b of each known terminal 2 and unknown terminal 3 drift with time mainly due to individual differences in the clock accuracy of the devices (in other words, between the terminals) ). Therefore, in order to improve the accuracy of position estimation of the unknown terminal 3, in order to improve the synchronization accuracy of the counter, the drift of the counter value of each known terminal 2 and unknown terminal 3 is corrected (each known terminal 2 or unknown terminal 3). It is effective to correct the processing delay (processing time difference) inside the.

  Therefore, as a procedure for correcting the counter value, first, the reference terminal 4 includes a radio signal (counter value) including a command for transmitting the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 to the coordinator 1. The request signal is wirelessly transmitted (broadcast) by the transmission / reception unit 4c (S7).

  Each known terminal 2 and unknown terminal 3 that have received the counter value request signal via the transmission / reception units 2c and 3c transmit / receive the counter value (referred to as the first counter value) extracted from the clock units 2b and 3b together with the terminal ID. Wireless transmission is performed to the coordinator 1 by 2c and 3c (S8).

The coordinator 1 includes the terminal ID and the first counter values C _2A-1 , C _2B-1 , C _2C-1 transmitted from each known terminal 2A, 2B, 2C and the terminal ID transmitted from the unknown terminal 3 A counter value C _3-1 is received, and the terminal ID and the data of the first counter values C _2A-1 , C _2B-1 , C _2C-1 , C _3-1 are used to estimate the position of the sensor terminal. 10 is output.

And the data input receiving part 11a of the control part 11 of the estimation apparatus 10 of a sensor terminal position is the 1st counter value _C2A-1 , _C2B-1 , _{C2C-1 of} each known terminal 2A, 2B, 2C, and The first counter value C _3-1 of the unknown terminal 3 is stored in the memory 15 in association with the terminal ID.

  Subsequently, after the elapse of a predetermined time interval t [seconds] from the processing of S7 (that is, transmission of the counter value request signal), the reference terminal 4 further counters the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3. A radio signal (counter value request signal) including a command to transmit a value to the coordinator 1 is transmitted (broadcast) by the transmission / reception unit 4c (S9).

  Note that the time interval t [seconds] from the process of S7 to the process of S9, in other words, the time interval t [seconds] of transmission of the counter value request signal by the reference terminal 4 is not limited to a specific value, For example, it is appropriately set in the range of about 5 to 60 [seconds].

  Each known terminal 2 and unknown terminal 3 that have received the counter value request signal via the transmission / reception units 2c and 3c transmit / receive the counter value (referred to as second counter value) extracted from the clock units 2b and 3b together with the terminal ID. Wireless transmission is performed to the coordinator 1 by 2c and 3c (S10).

The coordinator 1 sends the terminal IDs and second counter values C _2A-2 , C _2B-2 and C _2C-2 transmitted from the known terminals 2A, 2B and 2C and the terminal IDs and second IDs transmitted from the unknown terminal 3 respectively. The second counter value C _3-2 is received, and the terminal ID and the data of the second counter values C _2A-2 , C _2B-2 , C _2C-2 , C _3-2 are used to estimate the position of the sensor terminal. 10 is output.

And the data input receiving part 11a of the control part 11 of the estimation apparatus 10 of a sensor terminal position is the 2nd counter value _C2A-2 , _C2B-2 , _{C2C-2 of} each known terminal 2A, 2B, 2C, and The second counter value C _3-2 of the unknown terminal 3 is stored in the memory 15 in association with the terminal ID.

Next, the sensor terminal position estimating device 10 identifies each of the known terminal 2 and the unknown terminal 3 based on the terminal ID, while the time interval t, the first counter value C _2A-1, etc., and the second The counter error is calculated using the counter value C _{2A-2 and the} like (S11).

  The counter error is an index for correcting the counter value extracted from the clock units 2b and 3b of each known terminal 2 and unknown terminal 3 to the actual time, and may be an index that can correct the counter value to the actual time. For example, it is not limited to a specific index. Specifically, for example, an error per counter value that is a difference from the actual time per counter, a time counter ratio that is a ratio between the actual time and the counter value, and the like can be considered.

In the case of an error per counter value, specifically, for example, when the counter speed (time step, pitch) of the clock unit 2b of the known terminal 2 is 1 millisecond, it is known at the time interval t = 10 [seconds]. If the difference between the second counter value C _2A-2 of the terminal 2A and the first counter value C _2A-1 (ie, C _2A-2 -C _2A-1 ) is 10018, the counter value of the known terminal 2A The error per hit δ _2A = (10018−10000) /10000=+0.0018 [milliseconds / counter]. Similarly, an error δ _2B per counter value of the known terminal 2B, an error δ _2C per counter value of the known terminal 2C, and an error δ ₃ per counter value of the unknown terminal ₃ are calculated.

On the other hand, in the case of the time counter ratio, specifically, for example, when the counter speed (time step, pitch) of the clock unit 2b of the known terminal 2 is 1 millisecond, it is known at the time interval t = 10 [seconds]. If the difference between the second counter value C _2A-2 of the terminal 2A and the first counter value C _2A-1 (ie, C _2A-2 -C _2A-1 ) is 10018, the time counter of the known terminal 2A The ratio γ _2A = 10000/10018 [milliseconds / counter]. Similarly, the time counter ratio gamma _third time counter ratio gamma _2C and unknown terminal 3 of the time counter ratio gamma _2B and known terminal 2C of the known terminal 2B is calculated.

Specifically, the counter error calculation unit 11b of the control unit 11 includes first counter values C _2A-1 , C _2B-1 , _C1B-1 , _{C2B-1 of} the known terminals 2A, 2B, 2C stored in the memory 15 in the process of S8. C _2C-1 and the first counter value C _3-1 of the unknown terminal 3 are read from the memory 15 together with the terminal ID, and each known terminal 2A, 2B, 2C stored in the memory 15 in the process of S10. The second counter values C _2A-2 , C _2B-2 , C _2C-2 and the second counter value C _3-2 of the unknown terminal 3 are read from the memory 15 together with the terminal ID, and these first counters are read. Using the value C _2A-1 and the like, the second counter value C _{2A-2 and the} like and the value of the time interval t, the counter error such as the error δ per counter value and the time counter ratio γ is known terminal 2 and unknown Calculate for each terminal 3.

  Note that the value of the time interval t may be determined in advance as a data file, stored in the storage unit 12 or the like, and read by the counter error calculation unit 11b from the data file, or in the process of S9. Alternatively, the value input via the input unit 13 may be stored in the memory 15, and the counter error calculation unit 11b may read the value stored in the memory 15.

  Then, the counter error calculation unit 11b stores the calculated counter error value of each known terminal 2A, 2B, 2C and the counter error value of the unknown terminal 3 in the memory 15 in association with the terminal ID.

If the propagation speed of radio waves is 3 × 10 ⁸ m / sec, for example, the propagation time of 100 m is about 0.3 microseconds. Since this propagation time is very short, the difference in radio wave propagation time from the reference terminal 4 to each known terminal 2 and unknown terminal 3 due to the difference in position between each known terminal 2 and unknown terminal 3 and each known terminal 2 and unknown terminal 3 The difference in radio wave propagation time from 3 to the coordinator 1 is negligible.

  Next, the sensor terminal position estimation apparatus 10 corrects the trigger counter value transmitted from each known terminal 2 and unknown terminal 3 in the process of S6 using the counter error calculated in the process of S11 (S12). ).

Specifically, the counter value correction unit 11c of the control unit 11 includes the counter values C _2A , C _2B , C _2C at the time of triggering of the known terminals 2A, 2B, 2C stored in the memory 15 in the process of S6 and the unknown terminals. 3 the trigger time counter value C ₃ reads in from memory 15 of the memory each known terminal 2A stored in 15, 2B, 2C of the counter error value and the counter error value memory 15 of the unknown terminal 3 in the processing of S11 Read from.

  Then, the counter value correction unit 11c calculates the corrected trigger counter value by correcting the trigger counter value to the actual time for each known terminal 2 and unknown terminal 3.

For example, when the counter error index is an error δ per counter value, the corrected trigger counter value is calculated by subtracting δ per counter value from the trigger counter value (that is, for example, the known terminal 2A). , The counter value after trigger correction C _2A — _m = C _2A −δ _2A × C _2A ).

On the other hand, when the index of the counter error is the time counter ratio γ, the trigger time counter value is multiplied by the time counter ratio γ to calculate the corrected trigger time counter value (ie, for the known terminal 2A, for example). , Counter value at the time of trigger after correction C _{2A_m} = C _2A × γ _2A ).

  It should be noted that the post-correction trigger counter value, which is the counter value after trigger correction using the counter error, is the clock part of each known terminal 2 and unknown terminal 3 in the process of S2 based on the reset request signal in the process of S1. This is the actual elapsed time since the counter values 2b and 3b were reset.

The counter value correction unit 11c, each known terminal 2A calculated, 2B, 2C of the corrected trigger when the counter value C _{2A_m,} C _{2B_m,} C _{2C_m} and the terminal ID of the corrected trigger when the counter value C _{3_M} unknown terminal 3 And stored in the memory 15.

  Next, the sensor terminal position estimation device 10 uses the corrected trigger counter values of each known terminal 2 and unknown terminal 3 calculated in the processing of S12 to identify each known terminal while identifying based on the terminal ID. The distance L between 2 and the unknown terminal 3 is calculated (S13).

Specifically, since the reference terminal 4 is installed at the position of the unknown terminal 3, the corrected trigger counter values C _{2A_m} , C _{2B_m} , C _{2C_m of the} known terminals 2A, 2B, 2C and the unknown terminal 3 are corrected. Differences from the trigger counter value C 3 — _m (ie, C _{2A — m} −C 3 — _m , C _{2B — m —} C 3 — _m , C ₂ C — _{m —} C 3 — _m ) are sound propagation times from the unknown terminal 3 to the known terminals 2A, 2B and 2C. Therefore, the distances L _2A , L _2B , and L _2C between the known terminals 2A, 2B, and 2C and the unknown terminal 3 are calculated using the sound propagation speed (ie, sound speed = about 340 m / sec).

Therefore, the distance calculation unit 11d of the control unit 11 corrects the counter values C _{2A_m} , C _{2B_m} , C _{2C_m} after correction of the known terminals 2A, 2B, and 2C stored in the memory 15 in the process of S12 and the unknown terminals 3. The corrected trigger counter value C 3 — _m is read from the memory 15, and the difference between the counter values (ie, C _{2A — m} −C 3 — _m , C ₂ B — _{m —} C 3 — _m , C ₂ C — _{m —} C _{3 — m} ) is multiplied by the sound velocity to obtain each known terminal 2A, The distances L _2A , L _2B and L _2C between 2B and 2C and the unknown terminal 3 are calculated.

Then, the distance calculation unit 11 d stores the calculated values of the distances L _2A , L _2B , L _2C between the known terminals 2A, 2B, 2C and the unknown terminal 3 in the memory 15.

  Then, the sensor terminal position estimation device 10 estimates the position of the unknown terminal 3 from the distance L between each known terminal 2 and the unknown terminal 3 (S14).

Specifically, when the known terminals 2A, 2B, 2C and the unknown terminal 3 are on the same plane as in the example shown in FIG. 3, and the position of the unknown terminal 3 on the plane is estimated, The position of the unknown terminal 3 as an intersection of three circles centered on the positions of the known terminals 2A, 2B, 2C (note that these are known) and whose radii are L _2A , L _2B , L _2C , respectively. Is estimated. Specifically, for example, the position of the unknown terminal 3 is estimated by solving equations of three circles as simultaneous equations (including cases where the solutions are mathematically likely solutions).

  However, the position of the unknown terminal 3 can be narrowed down by the positional relationship with the known terminal 2, and two intersections derived by solving the equations of the two circles as simultaneous equations (that is, candidates for the position coordinates of the unknown terminal 3) If the position of the known terminal 3 can be identified from among the two, the number of known terminals 2 may be two, and the position of the unknown terminal 3 is estimated by solving two circle equations as simultaneous equations. Anyway.

  In addition, it is possible to improve the estimation accuracy of the position of the unknown terminal 3 in the plane space by using four or more known terminals 2 and solving equations of four or more circles as simultaneous equations.

  On the other hand, when the known terminal and the unknown terminal are three-dimensionally arranged and the position of the unknown terminal including the height is estimated, the radius of each known terminal The position of the unknown terminal is estimated as the intersection of the spheres, which is the distance to the unknown terminal. Specifically, for example, the position of an unknown terminal is estimated by using four known terminals and solving the equations of four spheres as simultaneous equations (including mathematically plausible solutions).

  However, the position of the unknown terminal can be narrowed down by the positional relationship with the known terminal, and from among the two intersections (that is, candidates for the position coordinates of the unknown terminal) derived by solving the equations of the three spheres as simultaneous equations When the position of the known terminal can be specified, the number of known terminals may be three, and the position of the unknown terminal may be estimated by solving three sphere equations as simultaneous equations.

  Note that, by using five or more known terminals and solving equations of five or more spheres as simultaneous equations, it is possible to improve the estimation accuracy of the position of the unknown terminal in the three-dimensional space.

The position estimation unit 11e of the control unit 11 reads the position (position coordinates) of each known terminal 2 from the known terminal position data file stored in advance in the storage unit 12, and stores each position stored in the memory 15 in the process of S13. The values of the distances L _2A , L _2B , L _2C between the known terminals 2A, 2B, 2C and the unknown terminal 3 are read from the memory 15 and used (for example, by solving simultaneous equations of circles as described above) ) Estimate the position of the unknown terminal 3.

  The method (1) described above has an advantage that it is only necessary to emit a reference sound once at the position of an unknown terminal.

(2) Method of installing reference terminal 4 at the position of known terminal 2 and generating sound Next, method of installing reference terminal 4 at the position of known terminal 2 and generating sound to estimate the position of unknown terminal 3 Will be described.

  The method of estimating the position of the sensor terminal in this method is a method of estimating the position of the unknown terminal 3 in a wireless sensor network including a plurality of known terminals 2 and a coordinator 1 as shown in FIGS. Yes, a step (S1) in which the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 are reset, a step in which a sound wave is transmitted at the position of the known terminal 2 (S5), and a sound wave input In response, a counter value at the time of sound wave input from the known terminal 2 and the unknown terminal 3 is transmitted to the coordinator 1 (S6), and a counter value request signal transmitted a plurality of times at a predetermined time interval t [seconds]. A plurality of counter values are transmitted from the known terminal 2 and the unknown terminal 3 to the coordinator 1 in response to the input (S7-S10), and these predetermined values A step of calculating a counter error, which is an index for correcting the counter value to the actual time, using the difference between the counter values transmitted at the time interval and the predetermined time interval t (S11) ), A counter value at the time of sound wave input of the known terminal 2 and a counter value at the time of sound wave input of the unknown terminal 3 are corrected by the counter error (S12), and the sound wave input time of the unknown terminal 3 corrected The distance L between the known terminal 2 and the unknown terminal 3 is calculated by multiplying the difference between the counter value of the known terminal 2 and the counter value at the time of the corrected sound wave input of the known terminal 2 by the sound propagation speed (S13). And the step of estimating the position of the unknown terminal 3 using the distance L between the plurality of known terminals 2 and the unknown terminal 3 (S15).

  The sensor terminal position estimation method can be realized as a sensor terminal position estimation apparatus. The sensor terminal position estimation apparatus 10 according to the present embodiment is an apparatus that estimates the position of an unknown terminal 3 in a wireless sensor network including a plurality of known terminals 2 and a coordinator 1. 3 and the counter values of the clock units 2b and 3b are reset and transmitted from the known terminal 2 and the unknown terminal 3 in response to the input of the sound wave transmitted at the position of the known terminal 2 and received by the coordinator 1. In response to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval t [seconds], the coordinator 1 receives the counter value at the time of sound wave input and is transmitted from the known terminal 2 and the unknown terminal 3 in response to the input of the counter value request signal. A data input receiving unit 11a as a means for receiving a plurality of received counter values, and counter values transmitted at predetermined time intervals A counter error calculation unit 11b as a means for calculating a counter error for each of the terminals 2 and 3 as an index for correcting the counter value to an actual time using the difference and a predetermined time interval t; A counter value correction unit 11c as means for correcting each of the counter value at the time of sound wave input and the counter value at the time of sound wave input of the unknown terminal 3 by a counter error; and the counter value at the time of sound wave input corrected by the unknown terminal 3; A distance calculation unit 11d as means for calculating the distance L between the known terminal 2 and the unknown terminal 3 by multiplying the difference between the corrected value of the known terminal 2 and the counter value at the time of sound wave input by the propagation speed of sound; A position estimation unit 11e serving as means for estimating the position of the unknown terminal 3 using the distance L between the plurality of known terminals 2 and the unknown terminal 3;

  The sensor terminal position estimation method and sensor terminal position estimation apparatus can also be realized by executing a sensor terminal position estimation program on a computer. Here, a case will be described in which the sensor terminal position estimation apparatus is realized and the sensor terminal position estimation method is executed by executing a sensor terminal position estimation program on a computer.

  FIG. 8 shows an overall configuration of a computer 10 (which is also a sensor terminal position estimation apparatus 10 in the present embodiment) for executing the sensor terminal position estimation program 17. The computer 10 (sensor terminal position estimating apparatus 10) includes a control unit 11, a storage unit 12, an input unit 13, a display unit 14, and a memory 15, and is connected to each other by a signal line such as a bus.

  Functions of the control unit 11, the storage unit 12, the input unit 13, the display unit 14, and the memory 15 constituting the computer 10 (sensor terminal position estimation apparatus 10) are the same as those described in the method (1).

  Then, the control unit 11 of the computer 10 (which is also the sensor terminal position estimation device 10 in this embodiment) executes a sensor terminal position estimation program 17 so that a plurality of known terminals 2 and the coordinator 1 are connected. In order to estimate the position of the unknown terminal 3 in the wireless sensor network including the information, the counter values of the clock units 2b and 3b between the known terminal 2 and the unknown terminal 3 are reset and transmitted at the position of the known terminal 2. In response to the input of the sound wave, a process of receiving the input of the counter value at the time of sound wave input transmitted from the known terminal 2 and the unknown terminal 3 and received by the coordinator 1 is performed, and a plurality of times are received at a predetermined time interval t [seconds]. Sent from the known terminal 2 and unknown terminal 3 in response to the input of the counter value request signal transmitted once, and received by the coordinator 1. The counter value is set to the actual time using the data input receiving unit 11a that performs processing for receiving the input of the plurality of counter values, the difference between the counter values transmitted at a predetermined time interval, and the predetermined time interval t. A counter error calculation unit 11b that performs processing for calculating a counter error, which is an index for correction, for each of the terminals 2 and 3, a counter value at the time of sound wave input of the known terminal 2, and a counter value at the time of sound wave input of the unknown terminal 3 And a counter value correction unit 11c that performs a process of correcting each of them by a counter error, and a difference between a counter value at the time of corrected sound wave input of the unknown terminal 3 and a counter value of the known terminal 2 at the time of sound wave input corrected A distance calculation unit 11d that performs a process of calculating the distance L between the known terminal 2 and the unknown terminal 3 by multiplying the propagation speeds of the two and the distance L between the plurality of known terminals 2 and the unknown terminal 3 A position estimation unit 11e to perform the process of estimating the position of the unknown terminal 3 is formed.

  Further, the coordinator 1 is electrically connected to the computer 10 (sensor terminal position estimating device 10) so that signals such as data and control commands can be transmitted and received (that is, input / output).

  Further, the position of each known terminal 2 (specifically, the position coordinates with an arbitrary point as the origin) is recorded in the known terminal position data file in association with the terminal ID, and stored in the storage unit 12 in advance. .

  In the method (2), the following processes from S1 to S13 are performed while the reference terminal 4 is installed at any position of the known terminals 2 and the known terminal 2 in which the reference terminal 4 is installed is changed. The processes from S5 to S13 are repeated as many times as necessary. In the following processing, since the position of the unknown terminal 3 is estimated based on the position of the reference terminal 4, the position of the reference terminal 4 is known so as to match the position of the known terminal 2 whose position is known. The reference terminal 4 is preferably installed at a position as close as possible to the terminal 2.

  The known terminal 2 in the following description refers to a known terminal in which the reference terminal 4 is installed at the terminal position, that is, any one of the known terminals 2A, 2B, and 2C.

  In this method, the terminal ID of the known terminal 2 (referred to as a calculation target known terminal) that is a calculation target of the distance from the unknown terminal 3 when the reference terminal 4 is installed in the sensor terminal position estimation apparatus 10 is also determined. Entered.

  First, the reference terminal 4 wirelessly transmits (broadcasts) a radio signal (referred to as a reset request signal) including a command for resetting the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 by the transmission / reception unit 4c (broadcast). S1).

  The known terminal 2 (including at least the calculation target known terminal) and the unknown terminal 3 that have received the reset request signal via the transmission / reception units 2c and 3c reset the counter values of the clock units 2b and 3b, The transmission / reception units 2c and 3c wirelessly transmit to the reference terminal 4 (S2).

  Here, when broadcasting, a known terminal other than the calculation target known terminal is also received or operated in accordance with the received signal, but in the following description, only the calculation target known terminal is focused. The coordinator 1 identifies each known terminal by a terminal ID transmitted from the known terminal. In some cases, the reference terminal 4 may identify each known terminal by the terminal ID transmitted from the known terminal as necessary.

  As a result, the counters of the calculation target known terminal 2 and the unknown terminal 3 that have received the reset request signal are synchronized (in other words, the counter values are aligned).

  Subsequently, the reference terminal 4 that has received reset signals from the calculation target known terminal 2 and the unknown terminal 3 via the transmission / reception unit 4c includes a command including a command for the known terminal 2 and the unknown terminal 3 to prepare a standby state for sound input. A signal (referred to as a standby request signal) is wirelessly transmitted (broadcast) by the transmission / reception unit 4c (S3).

  When the calculation target known terminal 2 and unknown terminal 3 that have received the standby request signal via the transmission / reception units 2c and 3c exceed the predetermined threshold (referred to as sound threshold) input to the sound wave reception units 2e and 3e. After the preparation for transmitting the counter value is completed, the standby signal is wirelessly transmitted to the reference terminal 4 by the transmission / reception units 2c and 3c (S4).

  Thereby, the calculation target known terminal 2 and the unknown terminal 3 that have received the standby request signal are ready to transmit the counter value when the input to the sound wave receiving units 2e and 3e exceeds the sound threshold. A trigger (that is, the input sound volume exceeds the sound threshold) is waited for.

  The concept of the sound threshold is the same as that in the description of the method (1) above.

  Here, the calculation target known terminal 2 and the unknown terminal 3 may be in a trigger waiting state by the calculation target known terminal 2 and the unknown terminal 3 autonomously. That is, the calculation target known terminal 2 and the unknown terminal 3 that have received the reset request signal wirelessly transmitted in the process of S1 reset the counter values of the clock units 2b and 3b, and then further adjust the trigger wait state. May be. In this case, the reset target signal is not wirelessly transmitted by the calculation target known terminal 2 and the unknown terminal 3 as in the process of S2, and the standby request signal is wirelessly transmitted by the reference terminal 4 as in the process of S3. Instead, the calculation target known terminal 2 and the unknown terminal 3 reset the counter value and prepare the trigger wait state, and wirelessly transmit the standby signal.

  Next, the reference terminal 4 that has received the standby signal from the calculation target known terminal 2 and the unknown terminal 3 via the transmission / reception unit 4c transmits a sound wave (referred to as a reference sound) by the sound wave transmission unit 4e (S5).

  The concept of the reference sound is the same as that in the description of the method (1) above.

  Then, when the input to the sound wave receiving units 2e and 3e exceeds the sound threshold, the calculation target known terminal 2 and the unknown terminal 3 have a counter value at that time (that is, a counter value at the time of sound wave input: a counter value at the time of triggering) And the terminal ID are wirelessly transmitted to the coordinator 1 by the transmission / reception units 2c and 3c (S6).

The coordinator 1 transmits the terminal ID and trigger counter value C ₂ transmitted from the known terminal 2 (specifically, the counter value C _{2A of} the known terminal _2A , the counter value C _{2B of} the known terminal _2B , and the counter value of the known terminal 2C). any) and which receives the terminal ID and the trigger when the counter value C ₃ transmitted from the unknown terminal 3 of the C _2C, the these terminal ID and the data of the trigger when the counter value C _2, C ₃ sensor terminal position It outputs to the estimation apparatus 10.

Then, the data input receiver 11a of the control unit 11 of the estimating device 10 of the sensor terminal position, a memory 15 and a trigger when the counter value C ₃ of the trigger when the counter value C and the unknown terminal 3 of known terminals in association with the terminal ID Remember me.

  Next, as a procedure for correcting the counter value, first, the reference terminal 4 includes a radio signal (counter) including a command for transmitting the counter values of the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3 to the coordinator 1. The value request signal is wirelessly transmitted (broadcasted) by the transmission / reception unit 4c (S7).

  The calculation target known terminal 2 and the unknown terminal 3 that have received the counter value request signal via the transmission / reception units 2c and 3c transmit and receive the counter value (referred to as the first counter value) extracted from the clock units 2b and 3b together with the terminal ID. The units 2c and 3c wirelessly transmit to the coordinator 1 (S8).

The coordinator 1 transmits the terminal ID and the first counter value C _2-1 (specifically, the counter value C _{2A-1 of} the known terminal _2A , the counter value C _{2B of the} known terminal 2B) transmitted from the calculation target known terminal 2. _-1 and any _one of the counter values C _2C-1 of the known terminal 2C), the terminal ID and the first counter value C _3-1 transmitted from the unknown terminal 3, and the terminal ID and the first The counter values C _2-1 and C _3-1 are output to the sensor terminal position estimation device 10.

Then, the data input receiver 11a of the control unit 11 of the estimating device 10 of the sensor terminal position, calculates the target first counter value C _3-1 known terminal first counter value C _2-1 of 2 and the unknown terminal 3 Are stored in the memory 15 in association with the terminal ID.

  Subsequently, after the elapse of a predetermined time interval t [seconds] from the processing of S7 (that is, transmission of the counter value request signal), the reference terminal 4 further counters the clock units 2b and 3b of the known terminal 2 and the unknown terminal 3. A radio signal (counter value request signal) including a command to transmit a value to the coordinator 1 is transmitted (broadcast) by the transmission / reception unit 4c (S9).

  The concept of the time interval t is the same as that in the description of the method (1) above.

  The calculation target known terminal 2 and the unknown terminal 3 that have received the counter value request signal via the transmission / reception units 2c and 3c transmit and receive the counter value (referred to as the second counter value) extracted from the clock units 2b and 3b together with the terminal ID. The parts 2c and 3c wirelessly transmit to the coordinator 1 (S10).

The coordinator 1 sends the terminal ID and the second counter value C _2-2 (specifically, the counter value C _{2A-2 of} the known terminal _2A , the counter value C _{2B of the} known terminal 2B) transmitted from the calculation target known terminal 2 _-2 or any one of the counter values C _2C-2 of the known terminal 2C), the terminal ID and the second counter value C _3-2 transmitted from the unknown terminal 3, and the terminal ID and the second The counter values C _2-2 and C _3-2 are output to the sensor terminal position estimating apparatus 10.

Then, the data input receiver 11a of the control unit 11 of the estimating device 10 of the sensor terminal position, calculates the target second counter value C _3-2 known terminal second counter value C _2-2 of 2 and the unknown terminal 3 Are stored in the memory 15 in association with the terminal ID.

Next, the sensor terminal position estimation apparatus 10 identifies the calculation target known terminal 2 and the unknown terminal 3 based on the terminal ID while identifying the time interval t, the first counter value _C2-1, and the second It calculates the counter errors by using the counter value C _2-2 (S11).

  The concept of the counter error is the same as that in the description of the method (1) described above. Specifically, for example, an error δ per counter value and a time counter ratio γ can be considered.

Counter error calculating unit 11b of the controller 11, the first counter value C _2-1 calculation target known terminal 2 stored in the memory 15 in the processing of S8 and a first counter value C _3-1 unknown terminal 3 preparative reads in from memory 15 together with the terminal ID, the second counter value C _2-2 calculation target known terminal 2 stored in the memory 15 in the processing of S10 and the second counter value C ₃ of the unknown terminal 3 _-2 is read from the memory 15 together with the terminal ID, and the first counter values _C2-1 and _C3-1 , the second counter values _C2-2 and _C3-2, and the value of the time interval t are read. Are used to calculate a counter error such as an error δ per counter value and a time counter ratio γ for each of the calculation target known terminals 2 and unknown terminals 3.

  Note that the value of the time interval t may be determined in advance as a data file, stored in the storage unit 12 or the like, and read by the counter error calculation unit 11b from the data file, or in the process of S9. Alternatively, the value input via the input unit 13 may be stored in the memory 15, and the counter error calculation unit 11b may read the value stored in the memory 15.

  Then, the counter error calculation unit 11b stores the calculated counter error value of the calculation target known terminal 2 and the counter error value of the unknown terminal 3 in the memory 15 in association with the terminal ID.

  Next, the sensor terminal position estimating apparatus 10 corrects the trigger counter value transmitted from the calculation target known terminal 2 and the unknown terminal 3 in the process of S6 using the counter error calculated in the process of S11 ( S12).

Specifically, the counter value correction unit 11c of the controller 11, a trigger time counter value C ₃ of the trigger when the counter value C ₂ and the unknown terminal 3 of the calculation target known terminal 2 stored in the memory 15 in the processing of S6 While reading from the memory 15, the counter error value of the calculation target known terminal 2 and the counter error value of the unknown terminal 3 stored in the memory 15 in the process of S 11 are read from the memory 15.

  Then, the counter value correction unit 11c calculates the corrected trigger counter value by correcting the trigger counter value to the actual time for each of the calculation target known terminal 2 and the unknown terminal 3.

  The method of calculating the post-correction trigger counter value is the same as in the description of the method (1) described above.

The counter value correction unit 11c (specifically, C _{2A_m,} C _{2B_m,} one of C _{2C_m)} calculated calculation target of known terminal 2 corrected trigger when the counter value C _{2_M} and unknown terminal 3 The corrected trigger counter value C 3 — _m is stored in the memory 15 in _association with the terminal ID.

  Next, the sensor terminal position estimation apparatus 10 uses the post-correction trigger time counter values of the calculation target known terminal 2 and the unknown terminal 3 calculated in the process of S <b> 12, and calculates between the calculation target known terminal 2 and the unknown terminal 3. The distance L is calculated (S13).

Specifically, since the reference terminal 4 is installed in the calculated position of the object known terminal 2, and the corrected trigger when the counter value of the corrected trigger when the counter value C _{3_M} calculation target known terminal 2 of the unknown terminal ₃ C 2_m of the difference _(i.e., C 3_m -C 2_m) because it is the sound propagation time from the calculation target the known terminal 2 to the unknown terminal 3, a distance L (specifically between the calculated target known terminal 2 and the unknown terminal 3 , L _2A , L _2B , or L _2C ) is calculated using the sound propagation speed (that is, sound speed = about 340 m / sec).

Therefore, the distance calculation section 11d of the control unit 11, the corrected trigger when the counter value of the stored calculation target known terminal 2 in the memory ₁₅ C 2_m and the corrected trigger when the counter value C _{3_M} unknown terminal 3 in the process at S12 read from the memory 15, the counter value of the difference _(i.e., C 3_m -C 2_m) calculating the distance L between the calculated target known terminal 2 and the unknown terminal 3 by multiplying speed of sound.

  Then, the distance calculation unit 11 d stores the calculated value of the distance L between the known terminal 2 and the unknown terminal 3 in the memory 15.

  The above-described processes from S1 to S13 or the processes from S5 to S13 are performed while the known terminal 2 where the reference terminal 4 is installed is changed (that is, while the known terminal 2 that is the calculation target known terminal is changed). Repeated as many times as necessary (S14: Yes).

  Specifically, as shown in FIG. 9, when the known terminal 2 and the unknown terminal 3 are on the same plane and the position of the unknown terminal 3 on the plane is estimated, in principle, three times. It repeats above, and the value of the distance between the three or more known terminals 2 and the unknown terminals 3 is calculated and stored in the memory 15.

  However, the position of the unknown terminal 3 can be narrowed down by the positional relationship with the known terminal 2, and two intersections (that is, the unknown terminal 3) derived by solving the equations of the two circles as simultaneous equations in the next processing of S15. 2), the number of known terminals 2 may be two, and the above-described processes from S1 to S13 or the processes from S5 to S13 are possible. May be repeated only twice, and the position of the unknown terminal 3 may be estimated by solving the equations of the two circles as simultaneous equations in the next processing of S15.

  Note that four or more known terminals 2 are used, and the above-described processing from S1 to S13 or the processing from S5 to S13 is repeated four or more times, and in the next processing of S15, equations of four or more circles are simultaneous equations. As a result, it is possible to improve the estimation accuracy of the position of the unknown terminal 3 in the planar space.

  On the other hand, when the known terminal and the unknown terminal are arranged three-dimensionally and the position of the unknown terminal including the height is estimated, in principle, it is repeated four or more times, and four or more known terminals and unknown terminals The value of the distance L is calculated and stored in the memory 15.

  However, the position of the unknown terminal can be narrowed down by the positional relationship with the known terminal, and two intersections (that is, position coordinates of the unknown terminal) derived by solving the equations of the three spheres as simultaneous equations in the next processing of S15. 3), the number of known terminals may be three, and the processes from S1 to S13 or the processes from S5 to S13 are repeated only three times. The position of the unknown terminal may be estimated by solving the equations of the three spheres as simultaneous equations in the next process of S15.

  It should be noted that five or more known terminals are used, and the above-described processing from S1 to S13 or the processing from S5 to S13 is repeated four or more times. In the next processing of S15, five or more sphere equations are used as simultaneous equations. By solving, it is possible to improve the estimation accuracy of the position of the unknown terminal in the three-dimensional space.

Here, as an example shown in FIG. 9, the above-described processes from S1 to S13 are repeated three times while the known terminal where the reference terminal 4 is installed is changed to the known terminal 2A, the known terminal 2B, and the known terminal 2C. Then, distances L _2A , L _2B , L _2C between the three known terminals 2A, 2B, 2C and the unknown terminal 3 are calculated and stored in the memory 15.

  Each known terminal 2 resets the counter values of the clock units 2b and 3b by wireless transmission (broadcast) of the reset request signal in the process of S1, and each known terminal by wireless transmission (broadcast) of the standby request signal in the process of S3. If the trigger wait state is arranged, it is not necessary to repeat the processing from S1 to S4 every time the known terminal 2 where the reference terminal 4 is installed is changed, that is, the processing from S5 to S13 is repeated. It ’s fine.

  Then, when the distance L between the known terminal 2 and the unknown terminal 3 of the number necessary for estimating the position of the unknown terminal 3 (and the number necessary for improving the estimation accuracy of the position of the unknown terminal) is calculated (S14). : No), the process proceeds to the next step S15.

  Then, the sensor terminal position estimation device 10 estimates the position of the unknown terminal 3 from the distance L between the plurality of known terminals 2 and the unknown terminal 3 (S15).

Specifically, when the three known terminals 2A, 2B, 2C and the unknown terminal 3 are on the same plane as in the example shown in FIG. 9, and the position of the unknown terminal 3 on the plane is estimated. Is an unknown terminal 3 as an intersection of three circles centered on the positions of three known terminals 2A, 2B, 2C (note that these are known) and whose radii are L _2A , L _2B , L _2C , respectively. Is estimated. Specifically, for example, the position of the unknown terminal 3 is estimated by solving equations of three circles as simultaneous equations (including cases where the solutions are mathematically likely solutions).

Therefore, the position estimation unit 11e of the control unit 11 reads the positions (position coordinates) of the three known terminals 2 from the known terminal position data file stored in advance in the storage unit 12, and stores them in the memory 15 in the process of S13. The values of the distances L _2A , L _2B , L _2C between the three known terminals 2A, 2B, 2C and the unknown terminal 3 are read from the memory 15 and used (for example, the simultaneous equations of circles as described above) To estimate the position of the unknown terminal 3.

  Note that, when generalized, when a plurality of known terminals and unknown terminals are on the same plane and the position of the unknown terminal on the plane is estimated, the known terminal on which the reference terminal is installed is changed. However, the above-described processing from S1 to S13 or the processing from S5 to S13 is repeated three or more times, centering on the positions of three or more known terminals (these are known) and each radius is The position of the unknown terminal is estimated as an intersection of three or more circles that are distances between the known terminal and the unknown terminal. Specifically, for example, the position of the unknown terminal is estimated by solving equations of three or more circles as simultaneous equations (including cases where the equations are plausible mathematically).

  However, the position of the unknown terminal can be narrowed down by the positional relationship with the known terminal, and from two intersections (that is, candidates for the position coordinates of the unknown terminal) derived by solving the equations of the two circles as simultaneous equations When the position of the known terminal can be specified, the process from S1 to S13 or the process from S5 to S13 is repeated twice while the known terminal where the reference terminal is installed is changed, and two circles are obtained. The position of the unknown terminal 3 may be estimated by solving these equations as simultaneous equations.

  The above-described processing from S1 to S13 or the processing from S5 to S13 is repeated four times or more while the known terminal where the reference terminal is installed is changed, and four or more circle equations are solved as simultaneous equations. Thus, it is possible to improve the estimation accuracy of the position of the unknown terminal 3 in the planar space.

  On the other hand, when the known terminal and the unknown terminal are arranged three-dimensionally and the position of the unknown terminal including the height is estimated, the above-described S1 to S13 are performed while the known terminal where the reference terminal is installed is changed. Or the process from S5 to S13 is repeated four or more times, and the center of the position of four or more known terminals and each radius is the distance between each known terminal and unknown terminal. The position of the unknown terminal is estimated as the intersection of the spheres. Specifically, for example, the position of an unknown terminal is estimated by solving equations of four or more spheres as simultaneous equations (including cases where the mathematically likely solution is included).

  However, the position of the unknown terminal can be narrowed down by the positional relationship with the known terminal, and from among the two intersections (that is, candidates for the position coordinates of the unknown terminal) derived by solving the equations of the three spheres as simultaneous equations When the position of the known terminal can be specified, the above-described processing from S1 to S13 or the processing from S5 to S13 is repeated three times while the known terminal where the reference terminal is installed is changed, and three spheres are obtained. The position of the unknown terminal may be estimated by solving these equations as simultaneous equations.

  In addition, the process from S1 to S13 or the process from S5 to S13 is repeated five times or more while the known terminal in which the reference terminal is installed is changed, and the equations of five or more spheres are solved as simultaneous equations. Thus, it is possible to improve the estimation accuracy of the position of the unknown terminal in the three-dimensional space.

  In the method (2) described above, the processes from S1 to S13 or the processes from S5 to S13 are repeated as many times as necessary to estimate the positions of a plurality of unknown terminals in the process of S15. There is an advantage that you can.

  According to the sensor terminal position estimation method, the estimation device, and the estimation program configured as described above, the counter value is transmitted using the counter value transmitted from the known terminal 2 and the unknown terminal 3 and the actual time interval t [seconds]. The counter error, which is an index for correcting the value to the actual time, is calculated for each of the terminals 2 and 3, and the counter value at the time of sound wave input of the known terminal 2 and the unknown terminal 3 is corrected using the counter error. Therefore, the difference between the counter value at the time of sound wave input of the known terminal 2 and the counter value at the time of sound wave input of the unknown terminal 3 is the actual sound propagation time between the both terminals 2 and 3. The distance L between the terminals 2 and 3 is accurately calculated by multiplying the difference between the counter value at the time of sound wave input (after correction) and the counter value at the time of sound wave input of the unknown terminal 3 (after correction) by the sound propagation speed. Possible to estimate Become.

  According to the sensor terminal position estimation method, the estimation apparatus, and the estimation program configured as described above, the position of the unknown terminal 3 can be estimated by transmitting and receiving sound waves. Without using expensive equipment, it is possible to accurately estimate the position of the sensor terminal constituting the wireless sensor network with a simple device configuration.

  In addition, although embodiment which implements the method of said (1) and the method of (2) is an example of the suitable form at the time of implementing this invention, embodiment of this invention is limited to the above-mentioned form However, the present invention can be variously modified without departing from the scope of the present invention. For example, in the above-described embodiment, a reference terminal 4 of a device that is separate from the coordinator 1, the known terminal 2, and the unknown terminal 3 that configure the wireless network (in other words, is not an essential element for configuring the wireless network) is prepared. However, the present invention is not limited to this, and in the case of the method (1), the unknown terminal 3 may have a function of transmitting a sound wave, and the sound wave may be transmitted. In the case of the method (2), each known terminal 2 may be provided with a function of transmitting a sound wave to transmit the sound wave.

  Further, in the above-described embodiment, the reference terminal 4 transmits the reset request signal wirelessly (S1), receives the reset signal, wirelessly transmits the standby request signal (S3), and receives the standby signal (S5). The two counter value request signals are transmitted wirelessly (S7, S9), but the present invention is not limited to this, and the coordinator 1 performs part or all of the wireless transmission of these signals and receives the corresponding signals. The coordinator 1 may perform this. In addition, when the coordinator 1 performs all of the wireless transmission of the signal, the reference terminal 4 may have a sound wave transmission function.

In the above-described embodiment, the reference terminal 4 wirelessly transmits a reset request signal (S1), and the known terminal 2 and the unknown terminal 3 that have received the signal reset the counter values of the clock units 2b and 3b and have been reset. The signal is wirelessly transmitted to the reference terminal 4 (S2). However, the present invention is not limited to this, and the reference terminal 4 (or coordinator 1) wirelessly transmits a counter value request signal as a process of S1, and the process of S2 As a process, the known terminal 2 and the unknown terminal 3 that have received the signal may wirelessly transmit the counter values of the clock units 2 b and 3 b to the coordinator 1. In this case, the counter values of the known terminal 2 and the unknown terminal 3 transmitted as the process of S2 are the initial counter values C _{2A_0} , C _{2B_0} , C _{2C_0} , C _{3_0,} and the trigger counter value transmitted in the process of S6 _{C 2A, C 2B, C 2C} , C 3 initial counter value C _{2A_0} from, C _{2B_0,} C _{2C_0,} the subtracting counter value C _{3_0 (i.e., C 2A -C 2A_0, C 2B} -C 2B_0, C 2C -C _{2C_0,} C ₃ -C _{3_0)} a may be used as a trigger when the counter value in the description of the above embodiments.

  In the above embodiment, the reference terminal 4 transmits a sound wave (S5), and the known terminal 2 and the unknown terminal 3 that have received the sound wave transmit the trigger counter value to the coordinator 1 (S6). The procedure related to correction (S7-S10) is performed, but the present invention is not limited to this, and as shown in FIG. 11, after performing the procedure (S5′-S8 ′) related to correction of the counter value, the reference terminal 4 transmits a sound wave (S9 ′), and the known terminal 2 and the unknown terminal 3 that have received the sound wave may transmit the trigger counter value to the coordinator 1 (S10 ′). Even in this case, the processing content after S11 is the same as that in the above-described embodiment.

  In the above-described embodiment, as a procedure related to the correction of the counter value, the transmission of the counter value request signal and the transmission of the counter value are repeated twice (that is, twice at S7 and S8 and S9 and S10). Second] and the difference between the counter values are used to calculate the counter error (S11). However, the present invention is not limited to this, and the transmission of the counter value request signal and the transmission of the counter value are not limited to this procedure. It may be repeated three or more times, and the counter error may be calculated using a plurality of combinations of the time interval t [second] and the counter value difference. Specifically, for example, it is conceivable to use an average value of counter errors or a median value calculated from each combination of a time interval t [seconds] and a difference between counter values. Further, the time interval t in this case may be constant or may vary. When the average value of the counter error or the median value is used, an error associated with the timing of acquiring the counter value (specifically, for example, a counter value of about ± 1 to 2 counts is assumed) occurs. However, since the influence of this error can be reduced, the counter error can be set to a more appropriate value (a value close to the true value).

  In the above-described embodiment, the counter value request signal is transmitted twice at a time interval t [seconds] as a procedure related to the correction of the counter value (S7 and S9). However, the present invention is not limited to this. As shown in FIG. 12, the time interval t may be started from the transmission of the reset request signal in the process of S1, and the counter value request signal may be transmitted only once (S7). In this case, the processes of S9 and S10 are not necessary, and the counter value (S8) transmitted as a response to the counter value request signal may be used as it is as the difference between the counter values in the process of S11.

Of course, it is possible to combine the above-described modifications of the embodiment. Specifically, for example, a processing procedure as shown in FIG. 13 is also conceivable. That is, first, the reference terminal 4 (or the coordinator 1) wirelessly transmits (broadcasts) the counter value request signal (S′1: processing corresponding to S7 in the above-described embodiment) and receives the counter value request signal. 2 and the unknown terminal 3 wirelessly transmit an initial counter value to the coordinator 1 (S′2: corresponding to S8), and the reference terminal 4 (or the coordinator 1) after the time interval t [seconds] has elapsed from the processing of S′1. ) Wirelessly transmits (broadcasts) the counter value request signal (S′3: corresponding to S9), and the known terminal 2 and the unknown terminal 3 that have received the counter value request signal send the second counter value to the coordinator 1. Radio transmission is performed (S′4: corresponding to S10). Thereby, counter values corresponding to the first counter value and the second counter value in the above-described embodiment are acquired. Next, the reference terminal 4 (or coordinator 1) wirelessly transmits (broadcasts) the standby request signal (S′5: corresponding to S3), and the known terminal 2 and the unknown terminal 3 that have received the standby request signal Is wirelessly transmitted to the reference terminal 4 (or the coordinator 1) (S′6: corresponding to S4). Subsequently, the reference terminal 4 transmits a sound wave (S′7: corresponding to S5), and the known terminal 2 and the unknown terminal 3 wirelessly transmit the counter value at the time of sound wave input to the coordinator 1 (S′8: (It is possible to correspond to S6). In this case, the initial counter values of the known terminal 2 and the unknown terminal 3 transmitted as the processing of S′2 are set to the first counter values C _2A-1 , C _2B-1 , C _2C-1 , C _3-1. And the second counter values C _2A-2 , C _2B-2 , C _2C-2 , C _{3-2 of the} known terminal 2 and the unknown terminal 3 transmitted as the processing of S′4. In addition, the initial counter values (first counter values) C _2A-1 and C _2B-1 are calculated from the counter values C _2A , C _2B , C _2C and C ₃ at the time of sound wave input transmitted in the processing of S′8. , C _2C-1 , C _3-1 minus counter values (ie, C _2A -C _2A-1 , C _2B -C _2B-1 , C _2C -C _2C-1 , C ₃ -C _3-1 ) May be used as a trigger counter value. Then, after the processing of S′8, the processing after S11 in the above-described embodiment may be performed in the same manner.

DESCRIPTION OF SYMBOLS 1 Coordinator 2 Known terminal 3 Unknown terminal 4 Reference terminal 10 Sensor terminal position estimation apparatus 11 Control section 12 Storage section 13 Input section 14 Display section 15 Memory 17 Sensor terminal position estimation program

Claims (21)

  A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position of the sensor terminal and the position are known A step of resetting a counter value of a clock unit with an unknown sensor terminal; a step of transmitting a sound wave at a position of the sensor terminal whose position is unknown; and a position of the position known in response to the input of the sound wave A counter value at the time of sound wave input from the sensor terminal and the sensor terminal whose position is unknown is transmitted to the coordinator, and responds to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval A plurality of counter values are obtained from the sensor terminal whose position is known and the sensor terminal whose position is unknown. A counter that is an index for correcting the counter value to an actual time by using the step transmitted to the notifier, the difference between the counter values transmitted at these predetermined time intervals, and the predetermined time interval An error is calculated for each sensor terminal, and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown are each The step of correcting by the counter error, the corrected counter value at the time of sound wave input of the sensor terminal having the known position, and the corrected counter value at the time of sound wave input of the sensor terminal having the unknown position; Is multiplied by the sound propagation speed to calculate the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown. And a step of estimating the position of the sensor terminal having the unknown position using the distance between the plurality of sensor terminals having the known position and the sensor terminal having the unknown position. A sensor terminal position estimation method characterized by the following.   A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position is in response to an input of a reset request signal A step of resetting counter values of clock portions of the sensor terminal having the known position and the sensor terminal having the unknown position; a step of transmitting a sound wave at the position of the sensor terminal having the unknown position; and In response to the input, a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown to the coordinator, and a predetermined value from the transmission of the reset request signal A sensor terminal whose position is known in response to an input of a counter value request signal transmitted at a time interval, and the position The counter value is transmitted to the coordinator from the sensor terminal having an unknown value, the counter value as a response to the counter value request signal and the predetermined time interval are used to set the counter value to an actual time. A counter error that is an index for correcting to the sensor terminal is calculated for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal with the known position, and the sound wave of the sensor terminal with the unknown position Each of the counter value at the time of input is corrected by the counter error, and the corrected counter value of the sound wave input of the sensor terminal whose position is known and the sensor terminal whose position is unknown are corrected. A sensor terminal whose position is known by multiplying the difference from the counter value at the time of sound wave input by the propagation speed of sound and the position The step of calculating the distance between the sensor terminal that is unknown, and the position between the sensor terminal whose position is known and the distance between the sensor terminal whose position is unknown is unknown. And a step of estimating the position of a certain sensor terminal.   A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, the position in response to an input of a counter value request signal An initial counter value is transmitted to the coordinator from a sensor terminal having a known position and a sensor terminal having an unknown position, and a counter value request transmitted at a predetermined time interval from the transmission of the counter value request signal A second counter value is transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown to the coordinator in response to input of a signal; and the sensor terminal whose position is unknown A step in which sound waves are transmitted at the position of the sensor, and a sensor whose position is known in response to the input of the sound waves A step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position and the position are unknown to the coordinator, a difference between the second counter value and the initial counter value, and the predetermined time interval A step of calculating for each sensor terminal a counter error that is an index for correcting the counter value to an actual time using the counter value at the time of sound wave input of the sensor terminal having the known position and the initial value The difference value between the counter value and the difference value between the counter value at the time of sound wave input of the sensor terminal whose position is unknown and the initial counter value are corrected by the counter error, and the position is known. The difference between the corrected difference value of a certain sensor terminal and the corrected difference value of a sensor terminal whose position is unknown is the sound propagation speed. A step of calculating a distance between the sensor terminal having the known position and the sensor terminal having the unknown position, a plurality of sensor terminals having the known position, and a sensor having the unknown position Estimating the position of the sensor terminal whose position is unknown using the distance to the terminal.   A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position of the sensor terminal and the position are known A step of resetting a counter value of a clock unit with an unknown sensor terminal, a step of transmitting a sound wave at a position of the sensor terminal where the position is known, and a position known in response to the input of the sound wave A counter value at the time of sound wave input from the sensor terminal and the sensor terminal whose position is unknown is transmitted to the coordinator, and responds to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval A plurality of counter values are obtained from the sensor terminal whose position is known and the sensor terminal whose position is unknown. A counter that is an index for correcting the counter value to an actual time by using the step transmitted to the notifier, the difference between the counter values transmitted at these predetermined time intervals, and the predetermined time interval An error is calculated for each sensor terminal, and a counter value at the time of sound wave input of a sensor terminal whose position is known and a counter value at the time of sound wave input of a sensor terminal whose position is unknown are each A step of correcting by the counter error, a corrected counter value at the time of sound wave input of the sensor terminal whose position is unknown, and a corrected counter value at the time of sound wave input of the sensor terminal having a known position; Is multiplied by the sound propagation speed to calculate the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown. And a step of estimating the position of the sensor terminal having the unknown position using the distance between the plurality of sensor terminals having the known position and the sensor terminal having the unknown position. A sensor terminal position estimation method characterized by the following.   A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position is in response to an input of a reset request signal A step of resetting counter values of clock portions of the sensor terminal having the known position and the sensor terminal having the unknown position; a step of transmitting a sound wave at the position of the sensor terminal having the known position; and In response to the input, a step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown to the coordinator, and a predetermined value from the transmission of the reset request signal A sensor terminal whose position is known in response to an input of a counter value request signal transmitted at a time interval, and the position The counter value is transmitted to the coordinator from the sensor terminal having an unknown value, the counter value as a response to the counter value request signal and the predetermined time interval are used to set the counter value to an actual time. A counter error that is an index for correcting to the sensor terminal is calculated for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal with the known position, and the sound wave of the sensor terminal with the unknown position Each of the counter value at the time of input is corrected by the counter error, and the corrected counter value at the time of the sound wave input of the sensor terminal whose position is unknown and the correction of the sensor terminal whose position is known are corrected. A sensor terminal whose position is known by multiplying the difference from the counter value at the time of sound wave input by the propagation speed of sound and the position The step of calculating the distance between the sensor terminal that is unknown, and the position between the sensor terminal whose position is known and the distance between the sensor terminal whose position is unknown is unknown. And a step of estimating the position of a certain sensor terminal.   A method for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, the position in response to an input of a counter value request signal An initial counter value is transmitted to the coordinator from a sensor terminal having a known position and a sensor terminal having an unknown position, and a counter value request transmitted at a predetermined time interval from the transmission of the counter value request signal A second terminal value is transmitted to the coordinator from a sensor terminal whose position is known and a sensor terminal whose position is unknown in response to an input of a signal; and a sensor terminal whose position is known A step in which sound waves are transmitted at the position of the sensor, and a sensor whose position is known in response to the input of the sound waves A step in which a counter value at the time of sound wave input is transmitted from the sensor terminal whose position and the position are unknown to the coordinator, a difference between the second counter value and the initial counter value, and the predetermined time interval A step of calculating for each sensor terminal a counter error that is an index for correcting the counter value to an actual time using the counter value at the time of sound wave input of the sensor terminal having the known position and the initial value A difference value between a counter value and a counter value at the time of sound wave input of a sensor terminal whose position is unknown and the initial counter value are corrected by the counter error; and the position is unknown The difference between the corrected difference value of a certain sensor terminal and the corrected difference value of the sensor terminal whose position is known is the sound propagation speed. A step of calculating a distance between the sensor terminal having the known position and the sensor terminal having the unknown position, a plurality of sensor terminals having the known position, and a sensor having the unknown position Estimating the position of the sensor terminal whose position is unknown using the distance to the terminal.   A counter value request signal is transmitted a plurality of times at a predetermined time interval, and a plurality of counter values are received from the sensor terminal having the known position and the sensor terminal having the unknown position in response to the input of the plurality of counter value request signals. Is transmitted to the coordinator, a counter error is calculated for each combination of the difference between the counter values and the predetermined time interval, and the average value or median value of the counter errors is used as the final counter error. The method of estimating a sensor terminal position according to any one of claims 1 to 6, wherein:   A device for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position of the sensor terminal and the position are known The sensor terminal whose position is known in response to the input of the sound wave transmitted at the position of the sensor terminal whose position is unknown after the counter value of the clock part with the unknown sensor terminal is reset and the position In response to an input of a counter value request signal transmitted a plurality of times at a predetermined time interval, and means for receiving an input of a counter value at the time of sound wave input transmitted from a sensor terminal having an unknown value received by the coordinator Transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator An indicator for correcting the counter value to an actual time using the means for receiving the input of the plurality of counter values, the difference between the counter values transmitted at the predetermined time interval, and the predetermined time interval A counter error for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and a counter value at the time of sound wave input of a sensor terminal whose position is unknown Means for correcting each by the counter error, a corrected counter value at the time of sound wave input of the sensor terminal whose position is known, and a corrected counter value at the time of sound wave input of the sensor terminal whose position is unknown A means for multiplying the difference between the sensor terminal and the sensor terminal whose position is unknown by multiplying the sound propagation speed by the sound propagation speed, and a plurality of means A sensor terminal comprising: means for estimating the position of the sensor terminal whose position is unknown using the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown Position estimation device.   A device for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position is in response to an input of a reset request signal In response to the input of the sound wave transmitted at the position of the sensor terminal whose position is unknown after the counter value of the clock part of the sensor terminal whose position is unknown and the sensor terminal whose position is unknown is reset. Means for receiving a counter value at the time of sound wave input transmitted from the sensor terminal whose position is unknown and the sensor terminal whose position is unknown and received by the coordinator, and a predetermined time interval from the transmission of the reset request signal In response to the input of the counter value request signal transmitted in the above, the sensor terminal whose position is known and the position are unknown Using the means for receiving the counter value transmitted from the sensor terminal and received by the coordinator, the counter value as a response to the counter value request signal, and the predetermined time interval, the counter value is converted into an actual time. Means for calculating a counter error, which is an index for correcting to each sensor terminal, a counter value at the time of the sound wave input of the sensor terminal whose position is known, and the sound wave input of the sensor terminal whose position is unknown Means for correcting each of the time counter value by the counter error, the corrected counter value of the sound wave input of the sensor terminal whose position is known, and the corrected sensor terminal of the sensor terminal whose position is unknown A sensor terminal whose position is known by multiplying the difference from the counter value at the time of sound wave input by the propagation speed of sound and the position unknown A sensor terminal whose position is unknown using means for calculating a distance between the sensor terminal and a plurality of sensor terminals whose position is known and the distance between the sensor terminal whose position is unknown An apparatus for estimating the position of a sensor terminal, comprising: means for estimating the position of the sensor terminal.   A device for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, and said position in response to an input of a counter value request signal Means for receiving an input of an initial counter value transmitted from a sensor terminal having a known position and a sensor terminal having an unknown position and received by the coordinator, and transmitted at a predetermined time interval from the transmission of the counter value request signal. In response to the input of the counter value request signal, means for receiving the input of the second counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator; In response to the input of the sound wave transmitted at the position of the sensor terminal where the position is unknown, the position is already Means for receiving a counter value input at the time of sound wave input transmitted from the sensor terminal and the sensor terminal whose position is unknown and received by the coordinator, and a difference between the second counter value and the initial counter value And means for calculating, for each sensor terminal, a counter error that is an index for correcting the counter value to an actual time using the predetermined time interval, and at the time of the sound wave input of the sensor terminal whose position is known Means for correcting each of a difference value between the counter value and the initial counter value and a difference value between the counter value at the time of sound wave input of the sensor terminal whose position is unknown and the initial counter value by the counter error; The corrected difference value of the sensor terminal whose position is known and the corrected difference value of the sensor terminal whose position is unknown Means for calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown by multiplying the sound propagation speed by a minute, a plurality of sensor terminals whose position is known, and the An apparatus for estimating a position of a sensor terminal, comprising: means for estimating the position of a sensor terminal whose position is unknown using the distance to the sensor terminal whose position is unknown.   A device for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position of the sensor terminal and the position are known The sensor terminal having the known position in response to the input of the sound wave transmitted at the position of the sensor terminal having the known position after the counter value of the clock unit with the unknown sensor terminal is reset and the position In response to an input of a counter value request signal transmitted a plurality of times at a predetermined time interval, and means for receiving an input of a counter value at the time of sound wave input transmitted from a sensor terminal having an unknown value received by the coordinator Transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator An indicator for correcting the counter value to an actual time using the means for receiving the input of the plurality of counter values, the difference between the counter values transmitted at the predetermined time interval, and the predetermined time interval A counter error for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and a counter value at the time of sound wave input of a sensor terminal whose position is unknown Means for correcting each by the counter error, a corrected counter value at the time of sound wave input of the sensor terminal whose position is unknown, and a corrected counter value at the time of sound wave input of the sensor terminal whose position is known A means for multiplying the difference between the sensor terminal and the sensor terminal whose position is unknown by multiplying the sound propagation speed by the sound propagation speed, and a plurality of means A sensor terminal comprising: means for estimating the position of the sensor terminal whose position is unknown using the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown Position estimation device.   A device for estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, wherein the position is in response to an input of a reset request signal In response to the input of the sound wave transmitted at the position of the sensor terminal having the known position after the counter value of the clock unit of the sensor terminal having the known position and the sensor terminal having the unknown position is reset. Means for receiving a counter value input at the time of sound wave input transmitted from the known sensor terminal and the sensor terminal whose position is unknown and received by the coordinator; and a predetermined time interval from transmission of the reset request signal In response to the input of the counter value request signal transmitted in the above, the sensor terminal whose position is known and the position are unknown Using the means for receiving the counter value transmitted from the sensor terminal and received by the coordinator, the counter value as a response to the counter value request signal, and the predetermined time interval, the counter value is converted into an actual time. Means for calculating a counter error, which is an index for correcting to each sensor terminal, a counter value at the time of the sound wave input of the sensor terminal whose position is known, and the sound wave input of the sensor terminal whose position is unknown Means for correcting each of the time counter value by the counter error, the corrected counter value of the sound wave input of the sensor terminal whose position is unknown, and the corrected sensor terminal of the position where the position is known A sensor terminal whose position is known by multiplying the difference from the counter value at the time of sound wave input by the propagation speed of sound and the position unknown A sensor terminal whose position is unknown using means for calculating a distance between the sensor terminal and a plurality of sensor terminals whose position is known and the distance between the sensor terminal whose position is unknown An apparatus for estimating the position of a sensor terminal, comprising: means for estimating the position of the sensor terminal.   A device for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, and said position in response to an input of a counter value request signal Means for receiving an input of an initial counter value transmitted from a sensor terminal having a known position and a sensor terminal having an unknown position and received by the coordinator, and transmitted at a predetermined time interval from the transmission of the counter value request signal. In response to the input of the counter value request signal, means for receiving the input of the second counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator; In response to the input of the sound wave transmitted at the position of the sensor terminal where the position is known, the position is already Means for receiving a counter value input at the time of sound wave input transmitted from the sensor terminal and the sensor terminal whose position is unknown and received by the coordinator, and a difference between the second counter value and the initial counter value And means for calculating, for each sensor terminal, a counter error that is an index for correcting the counter value to an actual time using the predetermined time interval, and at the time of the sound wave input of the sensor terminal whose position is known Means for correcting each of a difference value between the counter value and the initial counter value and a difference value between the counter value at the time of sound wave input of the sensor terminal whose position is unknown and the initial counter value by the counter error; The corrected difference value of the sensor terminal whose position is unknown and the corrected difference value of the sensor terminal whose position is known Means for calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown by multiplying the sound propagation speed by a minute, a plurality of sensor terminals whose position is known, and the An apparatus for estimating a position of a sensor terminal, comprising: means for estimating the position of a sensor terminal whose position is unknown using the distance to the sensor terminal whose position is unknown.   In response to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval, the sensor terminal whose position is known and the plurality of counters transmitted from the sensor terminal whose position is unknown and received by the coordinator A counter error is calculated for each combination of a difference between the counter values and the predetermined time interval, and an average value or a median value of the counter errors is used as the final counter error. The sensor terminal position estimating apparatus according to any one of claims 8 to 13.   A program for causing a computer to perform a process of estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the sound wave transmitted at the position of the sensor terminal whose position is unknown after the counter value of the clock unit of the sensor terminal which is and the position of the sensor terminal whose position is unknown is reset. A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal that is known and a sensor terminal whose position is unknown and received by the coordinator, and a counter value request that is transmitted a plurality of times at predetermined time intervals From the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to input of a signal The counter value is actually received using the process of receiving the input of the plurality of counter values received and received by the coordinator, the difference between the counter values transmitted at the predetermined time interval, and the predetermined time interval. A process of calculating a counter error, which is an index for correcting time, for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and the sound wave of the sensor terminal whose position is unknown A process of correcting each of the counter value at the time of input by the counter error, a correction of the counter value at the time of inputting the sound wave of the sensor terminal whose position is known, and a correction of the sensor terminal whose position is unknown The sensor terminal with the known position and the sensor with the unknown position are multiplied by the difference between the counter value at the time of the sound wave input and the sound propagation speed. The position of the sensor terminal whose position is unknown using the processing for calculating the distance to the terminal and the distance between a plurality of sensor terminals whose position is known and the sensor terminal whose position is unknown A program for estimating the position of a sensor terminal, which causes a computer to perform a process of estimating   A program for causing a computer to perform a process of estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input, a sound wave transmitted at the position of the sensor terminal whose position is unknown after the counter value of the clock unit of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset. A process of receiving a counter value at the time of sound wave input transmitted from the sensor terminal whose position is known in response to the input of the sensor and the sensor terminal whose position is unknown and received by the coordinator, and the reset request In response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the signal, the position is already set. A process of receiving a counter value transmitted from the sensor terminal and the sensor terminal whose position is unknown and received by the coordinator, a counter value as a response to the counter value request signal, and the predetermined time interval And calculating the counter error, which is an index for correcting the counter value to the actual time using each of the sensor terminals, the counter value at the time of the sound wave input of the sensor terminal having the known position, and the Processing for correcting each of the counter values at the time of the sound wave input of the sensor terminal whose position is unknown by the counter error, and the corrected counter values at the time of the sound wave input of the sensor terminal whose position is known and the position The position obtained by multiplying the difference from the corrected counter value at the time of sound wave input of the sensor terminal with unknown sound velocity by the sound propagation speed A process of calculating a distance between a sensor terminal having a known position and a sensor terminal having an unknown position, and a plurality of sensor terminals having the known position and the distance between the sensor terminal having an unknown position. A program for estimating the position of a sensor terminal, which causes a computer to perform a process of estimating the position of a sensor terminal whose position is unknown by using.   A program for causing a computer to perform processing for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, and a counter value request signal In response to the input, the process of receiving the input of the initial counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator, and transmission of the counter value request signal In response to the input of the counter value request signal transmitted at a predetermined time interval from the sensor terminal whose position is known and the second counter transmitted from the sensor terminal whose position is unknown and received by the coordinator Processing at the input of a value and at the position of the sensor terminal where the position is unknown. A process of receiving an input of a counter value at the time of sound wave input transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the sound wave, A process of calculating, for each sensor terminal, a counter error that is an index for correcting the counter value to an actual time using the difference between the second counter value and the initial counter value and the predetermined time interval; The difference between the counter value at the time of sound wave input of the sensor terminal with the known position and the initial counter value, and the difference between the counter value at the time of sound wave input of the sensor terminal with the unknown position and the initial counter value A process of correcting each of the values by the counter error, the corrected difference value of the sensor terminal whose position is known, and the position are unknown A process of calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown by multiplying the difference between the corrected difference value of the sensor terminal and the propagation speed of sound, Causing a computer to perform a process of estimating a position of a sensor terminal having an unknown position using the distance between a plurality of sensor terminals having the known position and a sensor terminal having an unknown position. A program for estimating a sensor terminal position as a feature.   A program for causing a computer to perform a process of estimating a position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to the input of the sound wave transmitted at the position of the sensor terminal where the position is known after the counter value of the clock part of the sensor terminal which is and the sensor terminal whose position is unknown is reset. A process of receiving a counter value input at the time of sound wave input transmitted from a sensor terminal that is known and a sensor terminal whose position is unknown and received by the coordinator, and a counter value request that is transmitted a plurality of times at predetermined time intervals From the sensor terminal whose position is known and the sensor terminal whose position is unknown in response to input of a signal The counter value is actually received using the process of receiving the input of the plurality of counter values received and received by the coordinator, the difference between the counter values transmitted at the predetermined time interval, and the predetermined time interval. A process of calculating a counter error, which is an index for correcting time, for each sensor terminal, a counter value at the time of sound wave input of the sensor terminal whose position is known, and the sound wave of the sensor terminal whose position is unknown A process of correcting each of the counter value at the time of input by the counter error, a correction of the counter value at the time of inputting the sound wave of the sensor terminal whose position is unknown, and a correction of the sensor terminal whose position is known The sensor terminal with the known position and the sensor with the unknown position are multiplied by the difference between the counter value at the time of the sound wave input and the sound propagation speed. The position of the sensor terminal whose position is unknown using the processing for calculating the distance to the terminal and the distance between a plurality of sensor terminals whose position is known and the sensor terminal whose position is unknown A program for estimating the position of a sensor terminal, which causes a computer to perform a process of estimating   A program for causing a computer to perform a process of estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator. In response to an input, a sound wave transmitted at the position of the sensor terminal whose position is known after the counter value of the clock unit of the sensor terminal whose position is known and the sensor terminal whose position is unknown is reset. A process of receiving a counter value at the time of sound wave input transmitted from the sensor terminal whose position is known in response to the input of the sensor and the sensor terminal whose position is unknown and received by the coordinator, and the reset request In response to the input of the counter value request signal transmitted at a predetermined time interval from the transmission of the signal, the position is already set. A process of receiving a counter value transmitted from the sensor terminal and the sensor terminal whose position is unknown and received by the coordinator, a counter value as a response to the counter value request signal, and the predetermined time interval And calculating the counter error, which is an index for correcting the counter value to the actual time using each of the sensor terminals, the counter value at the time of the sound wave input of the sensor terminal having the known position, and the Processing for correcting each of the counter values at the time of sound wave input of the sensor terminal whose position is unknown by the counter error, and the corrected counter values at the time of sound wave input of the sensor terminal whose position is unknown and the position The position obtained by multiplying the difference from the corrected counter value of the sound wave input of the sensor terminal with a known sound velocity by the sound propagation speed A process of calculating a distance between a sensor terminal having a known position and a sensor terminal having an unknown position, and a plurality of sensor terminals having the known position and the distance between the sensor terminal having an unknown position. A program for estimating the position of a sensor terminal, which causes a computer to perform a process of estimating the position of a sensor terminal whose position is unknown by using.   A program for causing a computer to perform processing for estimating the position of a sensor terminal whose position is unknown in a wireless sensor network including a plurality of sensor terminals whose positions are known and a coordinator, and a counter value request signal In response to the input, the process of receiving the input of the initial counter value transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator, and transmission of the counter value request signal In response to the input of the counter value request signal transmitted at a predetermined time interval from the sensor terminal whose position is known and the second counter transmitted from the sensor terminal whose position is unknown and received by the coordinator Processing that receives the input of a value, and the position of the sensor terminal where the position is known. A process of receiving an input of a counter value at the time of sound wave input transmitted from the sensor terminal whose position is known and the sensor terminal whose position is unknown and received by the coordinator in response to the input of the sound wave, A process of calculating, for each sensor terminal, a counter error that is an index for correcting the counter value to an actual time using the difference between the second counter value and the initial counter value and the predetermined time interval; The difference between the counter value at the time of sound wave input of the sensor terminal with the known position and the initial counter value, and the difference between the counter value at the time of sound wave input of the sensor terminal with the unknown position and the initial counter value Processing for correcting each of the values by the counter error, the corrected difference value of the sensor terminal whose position is unknown, and the position are known A process of calculating the distance between the sensor terminal whose position is known and the sensor terminal whose position is unknown by multiplying the difference between the corrected difference value of the sensor terminal and the propagation speed of sound, Causing a computer to perform a process of estimating a position of a sensor terminal having an unknown position using the distance between a plurality of sensor terminals having the known position and a sensor terminal having an unknown position. A program for estimating a sensor terminal position as a feature.   In response to the input of the counter value request signal transmitted a plurality of times at a predetermined time interval, the sensor terminal whose position is known and the plurality of counters transmitted from the sensor terminal whose position is unknown and received by the coordinator A counter error is calculated for each combination of a difference between the counter values and the predetermined time interval, and an average value or a median value of the counter errors is used as the final counter error. The sensor terminal position estimation program according to any one of claims 15 to 20.

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