JP4871034B2 - Radar device and reflection device - Google Patents

Description

  The present invention relates to a radar apparatus that radiates an electromagnetic wave and receives a reflected wave from a reflection apparatus such as a corner reflector that is a detection target and measures a distance, and a reflection apparatus that reflects an electromagnetic wave from the radar apparatus.

  In the distance measurement by the radar apparatus, the radar apparatus receives a reflected wave returning from the target by emitting an electromagnetic wave, and performs a distance measurement by applying a predetermined process to the reflected wave. At this time, it is easier to measure the distance of the target object when receiving a stronger reflected wave from a target having a large reflection cross section (RCS) among the reflected waves.

  However, there are various targets to be measured by the radar device, and the shape thereof is generally complicated, such as a car, a bicycle, a person, a structure, and the like. For this reason, the electromagnetic waves from the radar apparatus are reflected by those targets while being influenced by absorption and scattering, and the intensity received by the radar apparatus becomes complicated. Furthermore, when ranging in an environment in which various targets are mixed, it is difficult to measure a specific target.

  As a reflector that facilitates distance measurement in such an environment, a triangular corner reflector as shown in FIG. 41 is known. The corner reflector has a feature of efficiently reflecting the electromagnetic wave incident from the radar device in the incident direction, and can obtain a strong reflection intensity. Attaching the corner reflector to a specific target facilitates distance measurement by the radar device.

  In addition, an FMCW (Frequency Modulated-Continuous Wave) system is used as a radar system having a simple configuration capable of detecting a relative distance and a relative speed with respect to a target. The FMCW system radar modulates a millimeter wave band oscillation source with a triangular wave and transmits it, and mixes a part of the received wave and the transmitted wave reflected from the target, so that the distance R to the target and the relative velocity V The beat signal including the signal component is obtained (for example, see Non-Patent Document 1). There is also a high-performance FMCW radar that uses the millimeter wave band and is inexpensive and excellent in temperature stability (see, for example, Patent Document 1).

  As a conventional method for detecting the position of a mobile body using electromagnetic waves, hyperbolic navigation is known in which electromagnetic waves are transmitted and received between two fixed stations and the mobile body to recognize the position of the mobile body. It has been. Furthermore, GPS (Global Positioning System) is widely used as a system for detecting its absolute position.

  Patent Document 2 below relates to an active target detection system that transmits a radar wave, receives a return signal from a target, and detects a relative distance and a relative speed with respect to each target. In this system, the active target device amplifies and transmits the radar wave only when it receives its own ID.

  Patent Document 3 below relates to a modulation reflector attached to a target. The modulation reflector periodically changes the reflection cross section of the reflector regardless of what kind of transmission wave is received.

Patent Document 4 below relates to an obstacle detection system for identifying a specific object using an FMCW radar. In this system, the in-vehicle radar device transmits a startup wave and an exploration wave, and a wireless card carried by a pedestrian or the like transmits a response wave only for a predetermined period when receiving the startup wave.
“Basics and Applications of Millimeter-wave Technology”, Part 2 Chapter 2 4.5.2 FMCW Method, Issuer Realize Inc., pp. 233-234, 1998 JP-A-5-40169 JP 2005-17112 A JP 2001-330661 A Japanese Patent Laid-Open No. 2001-21644

The distance measurement using the conventional corner reflector described above has the following problems.
When ranging a plurality of targets having corner reflectors attached thereto, a specific target cannot be identified. Also, in an environment where a corner reflector and an object that generates a clutter component are mixed, it is difficult to identify whether the reflected wave is from a corner reflector or a clutter component when the two received intensities are equal.

Furthermore, with conventional GPS, it may be difficult to receive radio waves from GPS satellites due to the shade of the building and the weather.
An object of the present invention is to identify each target by a radar device in an environment where there are a plurality of targets to which reflectors such as corner reflectors are attached, or in an environment where a target and other objects are mixed. To measure the distance.

  FIG. 1 is a principle diagram of a radar apparatus and a reflection apparatus according to the present invention. The first and second radar apparatuses of the present invention include a transmission unit 101, a radar unit 102, and a position detection unit 103, radiate electromagnetic waves, receive a reflected wave from a reflector, and determine the position of the reflector. To detect. The first and second reflecting devices of the present invention include reflecting means 104, receiving means 105, and control means 106.

  In the first radar apparatus, the transmission unit 101 transmits activation information including information indicating the fluctuation frequency of the reflection cross section to the first reflection apparatus that reflects electromagnetic waves. The radar means 102 radiates electromagnetic waves to the first reflecting device, receives the reflected wave that changes at the fluctuating frequency from the first reflecting device, and acquires information on the relative distance from the reflected wave. The position detecting means 103 analyzes the reception levels of a plurality of received waves, extracts the reflected waves that change at the above-mentioned fluctuation frequency, and uses the relative distance information obtained from the reflected waves as the position information of the first reflecting device. Output as.

Information indicating the fluctuation frequency of the reflection cross-sectional area is stored in advance in the position detection means 103, for example.
In the first reflecting device, the reflecting means 104 reflects incident electromagnetic waves in the incident direction. The receiving means 105 receives activation information including information indicating the fluctuation frequency of the reflection cross section. The control means 106 changes the reflection sectional area of the reflection means 104 at the fluctuation frequency.

  According to the position detection system including the first radar device and the first reflection device, the reflection device changes the reflection cross-section according to the fluctuation frequency instructed by the radar device, so that a reflected wave including the frequency fluctuation is generated. The radar apparatus can identify the reception wave from the reflection apparatus that is the detection target by comparing the fluctuation frequency of the reception level of the reception wave with the instructed fluctuation frequency.

  In the second radar apparatus, the transmission unit 101 transmits activation information including information indicating the Doppler shift frequency to the second reflection apparatus that reflects electromagnetic waves. The radar means 102 radiates electromagnetic waves to the second reflecting device, receives a reflected wave with a Doppler shift of the Doppler shift frequency from the second reflecting device, and acquires information on the relative distance from the reflected wave. The position detection means 103 analyzes the signals of the plurality of received waves, extracts the reflected wave accompanied by the Doppler shift frequency, and obtains information on the relative distance obtained from the reflected wave of the second reflecting device. Output as position information.

Information indicating the Doppler shift frequency is stored in advance in the position detection means 103, for example.
In the second reflecting device, the reflecting means 104 reflects incident electromagnetic waves in the incident direction. The receiving means 105 receives activation information including information indicating the Doppler shift frequency. The control means 106 controls the operation of the reflection means 104 so as to generate a reflected wave with a Doppler shift of the Doppler shift frequency.

  According to the position detection system including the second radar device and the second reflection device, the reflection device generates a reflected wave with a Doppler shift according to the Doppler shift frequency instructed by the radar device. The radar device can identify the received wave from the reflection device that is the detection target by comparing the Doppler shift frequency of the received wave with the instructed Doppler shift frequency.

  The transmission unit 101 corresponds to, for example, a wireless transmission device 404, 1104, or a wireless communication device 1703, which will be described later, and the radar unit 102 corresponds to, for example, a millimeter wave FMCW radar unit 403, 1103, or 1702, which will be described later. The detection unit 103 corresponds to, for example, a position detection device 402, 1102, or 1701 described later.

  The reflection means 104 is, for example, a corner reflector 301, 1001-1, 1001-2, 1001-3, 1001-4, 2801, 2901, 3001, 3101, 3201, 3301, 3401, 3402, 3701, 3802-1, which will be described later. , 3802-2, or two-sided type reflector 3501.

  The reception unit 105 corresponds to, for example, the wireless reception devices 406 and 1106 or the wireless communication device 1705 described later, and the control unit 106 includes, for example, an RCS control unit 303, a Doppler shift frequency control unit 1004, and a control / drive unit described later. 2803, 2903, 3003, 3103, 3203, 3304, 3403, 3502, or the roll type driving device 3803.

  According to the present invention, when measuring the relative distance and relative speed of a fixed or moving object using a reflector such as a corner reflector with a radar device, the RCS or Doppler shift frequency of the reflector is characterized. The target can be identified, and high-precision measurement can be performed at low cost even in an environment where clutter occurs.

  Even when it is difficult to receive radio waves from GPS satellites due to the shadow of the building or the weather, the absolute position of the own station can be detected at low cost with the measurement accuracy of the radar device in the measurement range of the radar device.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
In the embodiment of the present invention, by controlling the RCS or Doppler shift frequency of the slave station at the master station, the RCS change or Doppler frequency of the slave station can be detected by the radar device of the master station even in an environment where clutter due to surrounding structures occurs. The position information of the slave station is clearly extracted.

  In the first embodiment, when measuring the relative distance from the slave station and further measuring the relative speed by the radar device of the master station, the master station uses the radio transmitter in advance to determine the RCS of the slave station at a specific cycle. The slave station is instructed to change, and the reception level change that matches the period instructed to the slave station is extracted from the distance measurement result of the radar apparatus of the master station. As a result, the position information of the slave station can be clearly extracted even in an environment in which clutter due to surrounding structures occurs.

  2 and 3 show an example of the appearance and configuration of the RCS variable device installed in the slave station. The RCS variable device includes a casing unit 201, a radome 202, a corner reflector 301, a motor unit 302, and an RCS control unit 303.

The inner and outer surfaces of the casing 201 and the rear surface of the corner reflector 301 are affixed with a radio wave absorbing material so that reflection of radio waves is suppressed as much as possible.
The RCS control unit 303 drives the motor unit 302 for a preset time according to the slave station activation information transmitted from the master station. This rotation time may be included in the slave station activation information transmitted from the master station. A corner reflector 301 is installed in the motor unit 302, and the corner reflector 301 rotates as the motor unit 302 rotates. Depending on the angle of the corner reflector 301, the RCS when viewed from the master station changes periodically.

  Note that when the corner reflector 301 is not rotating, the RSC variable device keeps the back of the corner reflector 301 with the radio wave absorbing material pasted to the master station as much as possible so that backscattering does not occur.

As described above, by mechanically changing the RCS of the corner reflector 301 and making the change cycle variable, it is possible to have different characteristics for each slave station, and it becomes easy to identify the slave station.
FIG. 4 shows the position detection system of the first embodiment. In this system, for example, the master station is installed on the ground and the slave station is installed on a moving object such as a vehicle in an environment where the clutter 411 from the surrounding structure 407 is generated. However, the installation status of the master station and slave stations is not fixed or fixed.

  The master station is composed of a position detection device 402, a millimeter wave FMCW radar unit 403, and a radio transmission device 404, and the slave station is composed of the RCS variable device 405 and the radio reception device 406 shown in FIGS. The

  FIG. 5 is an operation flowchart of the position detection device 402. The position detection device 402 checks the presence / absence of a slave station position detection instruction from the host device 401 (for example, a control device of the system) (step 501). When receiving the slave station position detection instruction, the wireless transmitter 404 is instructed to transmit slave station activation information including information of the RCS fluctuation frequency f1 Hz, and the millimeter wave FMCW radar unit 403 starts measurement. An instruction is issued (step 502).

  The wireless transmission device 404 generates a transmission packet including slave station activation information in accordance with an instruction from the position detection device 402, and transmits the packet. The millimeter wave FMCW radar unit 403 performs distance measurement for a preset time according to the measurement start instruction.

  The position detection device 402 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 403, and checks whether or not the reception level fluctuation of the frequency f1 Hz is included (step 503). Then, a target with the reception level fluctuation of the frequency is extracted, and the relative distance value and the relative speed value of the target are output to the host device 401 (step 504). On the other hand, when such a target cannot be extracted, information indicating that no slave station has been detected is output to the host device 401 (step 505).

The slave station wireless reception device 406 analyzes the received packet and outputs the slave station activation information included in the packet to the RCS control unit 303 of the RCS variable device 405.
FIG. 6 is an operation flowchart of the RCS control unit 303. The RCS control unit 303 checks whether or not the slave station activation information is input from the wireless reception device 406 (step 601).

  When the slave station activation information is input, the motor unit 302 is instructed to rotate at f1 Hz for X seconds in accordance with the information of the RCS fluctuation frequency f1 Hz (step 602). Accordingly, the corner reflector 301 reflects the electromagnetic wave 412 from the millimeter wave FMCW radar unit 403 to generate a backscattered wave while rotating at f1 Hz for X seconds.

  FIG. 7 shows an example of a radar ranging result when the slave station is activated. The reception level 702 of the radio wave from the slave station increases and decreases the threshold value T1 at a frequency of f1 Hz, and can be distinguished from the reception level 701 of clutter that does not vary. Note that the fluctuation frequency of the reception level 702 of the slave station can be obtained by counting the number of times of crossing the threshold value T1.

  The relative distance value 712 and the relative velocity value 722 (−Y1 km / h) of the slave station are extracted from the received wave of the target thus specified. Further, it is possible to extract the relative distance value 711 and the relative velocity value 721 (0 km / h) of the surrounding structure 407 from the clutter component.

  According to the first embodiment, the master station compares the RCS fluctuation frequency with the received wave intensity, and determines the distance measurement result that matches the change as the slave station. Therefore, even in an environment where clutter due to surrounding structures occurs. The relative distance and relative speed of the slave stations can be clearly distinguished.

  In the second embodiment, when there are a plurality of slave stations, when the slave station is instructed to change the RCS of the slave station at a specific period, the slave station ID is also specified, and the RCS of an arbitrary slave station is set. Control sequentially. Thereby, even in an environment where clutter is generated by surrounding structures, it is possible to clearly extract the position information of a plurality of slave stations.

  FIG. 8 shows a position detection system according to the second embodiment. In this system, for example, the master station 801 is installed on the ground and a plurality of slave stations 802-1 to 802-N are installed in a vehicle or the like in an environment where the clutter 811 from the surrounding structure 803 is generated. The configurations of the master station 801 and the slave stations 802-1 to 802-N are the same as those in the first embodiment. IDs 1 to IDN are assigned as identification information to the slave stations 802-1 to 802-N, respectively.

  The position detection device 402 receives a slave station position detection instruction designating a slave station ID for performing position detection from the host device 401, and in step 502 of FIG. 5, information on the RCS fluctuation frequency f1 Hz to the wireless transmission device 404. And an instruction to transmit slave station activation information including the slave station ID. In response to this, the wireless transmission device 404 generates a transmission packet including the slave station ID and transmits the packet.

In step 504, the position detection device 402 outputs the extracted relative distance value, relative speed value, and slave station ID of the target to the host device 401.
On the other hand, the radio reception devices 406 of the slave stations 802-1 to 802-N analyze the received packet and compare the slave station ID included in the packet with the own station ID. If the two match, the slave station activation information is output to the RCS control unit 303. On the other hand, if the slave station ID and the own station ID do not match, the slave station activation information is not output to the RCS control unit 303. In this case, the RCS control unit 303 maintains a state in which backscattering does not occur as much as possible with the rear surface of the corner reflector 301 facing the master station.

  According to the second embodiment, the RCS of the RCS variable device is changed only when the slave station receives the ID indicating the own station by wireless communication. Therefore, even in an environment where a plurality of slave stations exist, each child station The relative distance and relative speed of the station can be clearly distinguished.

  In the third embodiment, the master station instructs the slave station to change the Doppler shift frequency of the slave station at a specific frequency using a wireless transmission device in advance, and from the distance measurement result of the radar device of the master station, Extract the Doppler shift frequency that matches the frequency instructed to the station. As a result, the position information of the slave station can be clearly extracted even in an environment in which clutter due to surrounding structures occurs.

  9 and 10 show an example of the appearance and configuration of a Doppler shift frequency variable device installed in a slave station. The Doppler shift frequency variable device includes a casing 901, a radome 902, corner reflectors 1001-1 to 1001-4, a corner reflector rotating unit 1002, a motor unit 1003, and a Doppler shift frequency control unit 1004.

The inner and outer surfaces of the housing portion 901 and the rear surfaces of the corner reflectors 1001-1 to 1001-4 are each attached with a radio wave absorbing material so that reflection of radio waves is suppressed as much as possible.
The Doppler shift frequency control unit 1004 drives the motor unit 1003 for a preset time according to the slave station activation information transmitted from the master station. This rotation time may be included in the slave station activation information transmitted from the master station. The motor unit 1003 is connected to the corner reflector rotating unit 1002, and the corner reflector rotating unit 1002 rotates as the motor unit 1003 rotates, and the corner reflectors 1001-1 to 1001-connected to the corner reflector rotating unit 1002. 4 has a structure that rotates in the backscattering direction (or the reverse direction) of the radar wave.

Depending on the rotation speed of the corner reflectors 1001-1 to 1001-4, a Doppler shift occurs in the reflected wave received by the master station.
FIG. 11 shows a position detection system according to the third embodiment. In this system, for example, a master station is installed on the ground and a slave station is installed on a moving object such as a vehicle in an environment in which clutter 1111 from surrounding structures 1107 is generated.

  The master station includes a position detection device 1102, a millimeter wave FMCW radar unit 1103, and a wireless transmission device 1104. The slave station includes the Doppler shift frequency variable device 1105 and the wireless reception device 1106 shown in FIGS. Composed.

  FIG. 12 is an operation flowchart of the position detection apparatus 1102. The position detection device 1102 checks the presence / absence of a slave station position detection instruction from the higher-level device 1101 (for example, a system control device) (step 1201). Upon receiving the slave station position detection instruction, the wireless transmitter 1104 is instructed to transmit slave station activation information including information on the Doppler shift frequency faHz, and the millimeter wave FMCW radar unit 1103 starts measurement. An instruction is issued (step 1202).

  Radio transmission apparatus 1104 generates a transmission packet including slave station activation information in accordance with an instruction from position detection apparatus 1102 and transmits the packet. The millimeter wave FMCW radar unit 1103 performs distance measurement for a preset time in accordance with the measurement start instruction.

  The position detection device 1102 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 1103 and checks whether or not a Doppler shift of the frequency faHz is included (step 1203). The beat signal of the distance measurement result includes information on the Doppler shift frequency of the received wave, which is compared with faHz. Then, a target with a faHz Doppler shift is extracted, and the relative distance value and relative velocity value of the target are output to the host device 1101 (step 1204). On the other hand, when such a target cannot be extracted, information indicating that no slave station has been detected is output to the host device 1101 (step 1205).

  The slave station wireless reception device 1106 analyzes the received packet and outputs the slave station activation information included in the packet to the Doppler shift frequency control unit 1004 of the Doppler shift frequency variable device 1105.

  FIG. 13 is an operation flowchart of the Doppler shift frequency control unit 1004. The Doppler shift frequency control unit 1004 checks whether or not the slave station activation information is input from the wireless reception device 1106 (step 1301).

  When the slave station activation information is input, the motor unit 1003 is instructed to rotate at fb Hz for X seconds in accordance with the information of the Doppler shift frequency faHz (step 1302). As a result, the corner reflectors 1001-1 to 1001-4 reflect the electromagnetic wave 1112 from the millimeter wave FMCW radar unit 1103 while rotating at fb Hz for X seconds to generate a backscattered wave.

By the way, the Doppler shift frequency faHz observed by the master station can be expressed by the following equation.

fa = 2 × v × f0 / c (1)

v: Relative speed of target object f0: Transmission frequency (Hz)
c: speed of light

Therefore, the Doppler shift frequency can be adjusted by the rotation direction and rotation speed of the corner reflectors 1001-1 to 1001-4. For the transmission frequency f0, the Doppler shift frequency is added to the + side when the target approaches the master station, and the Doppler shift frequency is added to the-side when moving away.

When the master station and the slave station are both stationary and the corner reflectors 1001-1 to 1001-4 rotate on the circumference of the radius r as shown in FIG. 14, the relative speed v is expressed by the following equation. The

v = 2 × π × r × fb (2)

For example, the relative speed v for obtaining a Doppler shift frequency fa of 2 kHz at a transmission frequency of 70 GHz is about 4.3 m / s from the equation (1). Here, if the radius r is 0.25 m, the rotation frequency fb of the motor unit 1003 is about 2.73 Hz from the equation (2).

  FIG. 15 shows an example of a radar ranging result when the slave station is activated. Reception levels 1501 and 1502 represent reception levels of radio waves from clutter and slave stations, respectively. A relative distance value 1511 and a relative velocity value 1521 (0 km / h) of the surrounding structure 1107 are extracted from the clutter component, and a relative distance value 1512 and a relative velocity value 1522 (− Y2 km / h) is extracted.

  Since the relative velocity value 1522 is a value corresponding to the Doppler shift frequency faHz, the target can be specified by this value, and the relative distance value 1512 of the target can be extracted.

  According to the radar using the FMCW method, it is possible to obtain both the relative distance and the relative speed of the slave station by one distance measurement. Therefore, if the slave station is stationary, the relative speed value is detected in a situation where the relative distance does not change. Here, the rotation speed v of the corner reflectors 1001-1 to 1001-4 corresponding to the Doppler shift frequency faHz is subtracted from the measured relative speed value. Can be confirmed.

  On the other hand, when the vehicle in which the slave station is installed is moving, the relative speed of the vehicle is obtained by taking the difference between the measured Doppler shift frequency of the target and the Doppler shift frequency faHz specified by the position detection device 1102. Can be calculated. Specifically, the result of subtracting the rotational speeds of the corner reflectors 1001-1 to 1001-4 from the measured relative speed value is the relative speed value of the vehicle.

  According to the third embodiment, the master station compares the instructed Doppler shift frequency with the Doppler shift frequency of the received wave, and determines the distance measurement result that matches the frequency as the slave station. Even in the environment where it occurs, the relative distance of the slave stations can be clearly determined.

  In the fourth embodiment, when there are a plurality of slave stations, when a specific Doppler shift frequency is instructed to the slave station, the slave station ID is also specified, and the Doppler shift frequency of any slave station is sequentially controlled. Thereby, even in an environment where clutter is generated by surrounding structures, it is possible to clearly extract the position information of a plurality of slave stations.

  FIG. 16 shows a position detection system according to the fourth embodiment. In this system, for example, the master station 1601 is installed on the ground and a plurality of slave stations 1602-1 to 1602-N are installed in a vehicle or the like in an environment where the clutter 1611 from the surrounding structure 1603 is generated. The configurations of the master station 1601 and the slave stations 1602-1 to 1602-N are the same as those in the third embodiment. IDs 1 to IDN are assigned as identification information to the slave stations 1602-1 to 1602-N, respectively.

  The position detection apparatus 1102 receives a slave station position detection instruction designating a slave station ID for performing position detection from the host apparatus 1101, and in step 1202 of FIG. 12, information on the Doppler shift frequency faHz is transmitted to the wireless transmission apparatus 1104. And an instruction to transmit slave station activation information including the slave station ID. In response to this, the wireless transmission device 1104 generates a transmission packet including the slave station ID and transmits the packet.

In step 1204, the position detection device 1102 outputs the extracted relative distance value, relative speed value, and slave station ID of the target to the host device 1101.
On the other hand, the wireless reception devices 1106 of the slave stations 1602-1 to 1602-N analyze the received packet and compare the slave station ID included in the packet with the own station ID. If they match, the slave station activation information is output to the Doppler shift frequency control unit 1004. On the other hand, if the slave station ID and the own station ID do not match, the slave station activation information is not output to the Doppler shift frequency control unit 1004.

  According to the fourth embodiment, the Doppler shift frequency of the Doppler shift frequency variable device is changed only when the slave station receives the ID indicating the own station by wireless communication. Therefore, even in an environment where there are a plurality of slave stations. The relative distance and relative speed of each slave station can be clearly discriminated.

  In the fifth embodiment, the master station and the slave station include a wireless communication device, and perform bidirectional communication between the master station and the slave station. The master station instructs the slave station in advance to change the RCS of the slave station at a specific cycle using the wireless communication device, and the slave station notifies the master station of a response to the instruction from the master station. To do. As a result, the master station recognizes the presence of the slave station, performs distance measurement by the radar device, and extracts a reception level change that coincides with the period instructed to the slave station from the distance measurement result. Thus, the position information of the slave station can be clearly extracted even in an environment in which clutter due to surrounding structures occurs.

  FIG. 17 shows a position detection system according to the fifth embodiment. In this system, for example, the master station is installed on the ground and the slave station is installed on a moving object such as a vehicle in an environment in which clutter 1711 from the surrounding structure 1706 is generated.

  The master station includes a position detection device 1701, a millimeter wave FMCW radar unit 1702, and a wireless communication device 1703. The slave station includes the RCS variable device 1704 and the wireless communication device 1705 shown in FIGS. The

  The position detection device 1701 receives a slave station position detection instruction from the host device 401 and issues a transmission instruction of slave station activation information including information on the RCS fluctuation frequency f1 Hz to the wireless communication device 1703.

  The wireless communication device 1703 generates an activation instruction packet including slave station activation information in accordance with an instruction from the position detection device 1701, and transmits the packet to the wireless communication device 1705 for a preset time.

  When there is a slave station, that is, when the wireless communication device 1705 receives a packet transmitted from the wireless communication device 1703 within a preset time, the wireless communication device 1705 transmits the slave station activation information to the RCS variable device. At the same time, the response packet is transmitted to the wireless communication apparatus 1703.

  The wireless communication apparatus 1703 receives the response packet from the slave station, notifies the position detection apparatus 1701 of the presence of the slave station, and the position detection apparatus 1701 issues a measurement start instruction to the millimeter wave FMCW radar unit 1702. put out.

The millimeter wave FMCW radar unit 1702 performs distance measurement for a preset time according to the measurement start instruction.
The position detection device 1701 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 1702, extracts a target with a reception level variation of the frequency f1 Hz, and sets the relative distance value and relative velocity value of the target as a host device. 401 is output.

  On the other hand, when there is no slave station, that is, when the wireless communication device 1703 does not receive a response packet within a preset time, the wireless communication device 1703 does not notify the position detection device 1701 of the presence of the slave station. . In this case, the position detection device 1701 outputs information indicating that a slave station has not been detected to the host device 401.

According to the fifth embodiment, when the position of a slave station is detected, it is possible to construct a system that suppresses unnecessary transmission of radar waves and avoids radio wave interference as much as possible.
In the sixth embodiment, when the master station is a mobile station and the slave station is a fixed station, and there are a plurality of slave stations, the mobile station has a plurality of fixed stations obtained by wireless communication with the plurality of fixed stations. The position information of the mobile station is calculated using the absolute position information and the distance measurement result by the radar device. As a result, even in an environment in which clutter due to surrounding structures occurs, the position information of the mobile station can be clearly extracted.

  FIG. 18 shows a position detection system according to the sixth embodiment. In this system, in an environment where clutter 1811 from surrounding structures 1803 is generated, the master station 1801 is a mobile station installed in a vehicle or the like, and a plurality of slave stations 1802-1 to 1802-N are installed on the ground. It is a fixed station. The configurations of the master station 1801 and the slave stations 1802-1 to 1802-N are the same as those in the fifth embodiment. IDs 1 to IDN are assigned as identification information to the slave stations 1802-1 to 1802-N, respectively.

  As the antenna scan function of the millimeter wave FMCW radar unit 1702 in the master station 1801, any method such as a mechanical scanning method or an electronic scanning method may be used.

  The position detection device 1701 of the master station 1801 that is a mobile station receives a position detection instruction for the slave station that is a fixed station from the host device 401, and sets a plurality of slave station IDs and slave station IDs to the wireless communication device 1703. An instruction to transmit slave station activation information including information on the corresponding RCS fluctuation frequencies f1 Hz to fNHz is issued. In response to this, the wireless communication device 1703 generates a transmission packet including the slave station activation information in accordance with the instruction from the position detection device 1701, and the slave stations 1802-1 to 1802 -N for a preset time. A packet is transmitted to the wireless communication apparatus 1705.

  The wireless communication apparatus 1705 analyzes the received packet, and compares the slave station ID included in the packet with its own station ID. If they match, the slave station activation information is output to the RCS variable device 1704 and a response packet including the absolute position information of the slave station is transmitted to the wireless communication device 1703 of the master station 1801.

  On the other hand, if the slave station ID and the own station ID do not match, the slave station activation information is not output to the RCS variable device 1704. In this case, the RCS variable device 1704 maintains a state in which back scattering does not occur as much as possible with the rear surface of the corner reflector 301 facing the master station.

  When there are two or more slave stations, that is, when the wireless communication device 1703 of the master station 1801 receives a response packet from the wireless communication devices of two or more slave stations within a preset time, The communication device 1703 notifies the position detection device 1701 of the slave station ID and the slave station absolute position information. The position detection device 1701 issues a measurement start instruction to the millimeter wave FMCW radar unit 1702.

The millimeter wave FMCW radar unit 1702 performs distance measurement by scanning the antenna for a preset time in accordance with the measurement start instruction.
The position detection device 1701 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 1702 and the antenna scan information, and extracts two or more targets from the distance measurement result with the reception level fluctuation of the frequency f1 Hz to fNHz. . Then, the position information of the master station 1801 is calculated from the extracted relative distance value of the target, antenna scan information, and target absolute position information, and is output to the host device 401. As the antenna scan information, angle information of the target with respect to the traveling direction of the mobile station is used.

  If there is no slave station or if only one slave station is detected, the position information of the master station 1801 cannot be calculated. Therefore, the position detection device 1701 outputs information that the slave station has not been detected to the host device 401.

  FIG. 19 shows the positional relationship between the mobile station 1801 and the fixed stations 1802-1 and 1802-2. The position detection device 1701 of the mobile station 1801 includes coordinates (X1, Y1) and (X2, Y2) which are absolute position information of the fixed stations 1802-1 and 1802-2 obtained by wireless communication, and a distance measurement result by the radar device. From the relative distances A and B between the fixed stations 1802-1 and 1802-2 obtained from the above and the angles α and β of the fixed stations 1802-1 and 1802-2 with respect to the mobile station traveling direction obtained from the antenna scan information. Position information can be calculated.

  FIG. 20 shows an example of radar ranging results when the fixed stations 1802-1 and 1802-2 are activated. The reception level 2001 of radio waves from the fixed station 1802-1 increases and decreases the threshold T2 at a frequency of f1 Hz, and the reception level 2002 of radio waves from the fixed station 1802-2 increases and decreases the threshold T2 at a frequency of f2 Hz. The relative distance value and relative velocity value of each of the fixed stations 1802-1 and 1802-2 can be extracted. Note that the fluctuation frequency of the reception level can be obtained by counting the number of times of crossing the threshold value T2.

  According to the sixth embodiment, for example, even when radio waves used in an existing position detection system such as GPS are difficult to receive due to the shadow of a building or the weather, the absolute position of the local station is highly accurate in the measurement range of the radar device. It is possible to construct a system that can be detected easily.

  In the seventh embodiment, when there are a plurality of master stations, when instructing the slave station to change the RCS of the slave station at a specific frequency, or when instructing the slave station to a specific Doppler shift frequency, Notification of master station ID and designation of slave station ID are performed. In addition, when an arbitrary slave station controls the RCS or Doppler shift frequency, the slave station uses a combination of a plurality of RCS changes or a combination of a plurality of Doppler shift frequencies to digitally convert the bidirectional scattered wave of the radar. The computerized slave station ID or master station ID is added. Thereby, the master station can clarify that the slave station is operating with the content instructed by the master station, and can extract the location information of the slave station.

  FIG. 21 shows a position detection system according to the seventh embodiment. This system includes a plurality of master stations 2102-1 and 2102-2 and a plurality of slave stations 2103-1 and 2103-2 in an environment in which clutter from surrounding structures occurs. However, the installation status of the master station and slave stations is not fixed or fixed.

  When using the RCS variable device, the configurations of the master stations 2102-1 and 2102-2 and the slave stations 2103-1 and 2103-2 are the same as those in the first embodiment. “01” and “02” are assigned as identification information (decimal numbers) to the master stations 2102-1 and 2102-2, respectively, and “11” and “12” are assigned to the slave stations 2103-1 and 2103-2, respectively. "Is assigned as identification information (decimal number). The master station 2102-1 operates according to an instruction from the host device 2101-1, and the master station 2102-2 operates according to an instruction from the host device 2101-2.

  FIG. 22 is an operation flowchart of the position detection apparatus 402 when the master station 2102-1 detects the slave station 2103-1. The position detection device 402 checks the presence / absence of a slave station position detection instruction from the host device 2101-1 (step 2201). When receiving the slave station position detection instruction specifying the slave station 2103-1 ID “11”, the wireless transmitter 404 is notified of the master station 2102-1 ID “01” and the slave station 2103-1 ID. An instruction to transmit slave station activation information including “11” is issued, and a measurement start instruction is issued to the millimeter wave FMCW radar unit 403 (step 2202).

  The wireless transmission device 404 generates a transmission packet including the ID “01” of the master station 2102-1 and the ID “11” of the slave station 2103-1 in accordance with an instruction from the position detection device 402, and transmits the packet. The millimeter wave FMCW radar unit 403 performs distance measurement for a preset time according to the measurement start instruction.

  The position detection device 402 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 403, and changes the reception level indicating the ID “01” of the master station 2102-1 and the ID “11” of the slave station 2103-1. Is checked (step 2203). Then, a target with such reception level fluctuation is extracted, and the relative distance value and relative speed value of the target are output to the higher-level apparatus 2101-1 as information of the slave station 2103-1 (step 2204). On the other hand, when such a target could not be extracted, information indicating that no slave station has been detected is output to the higher-level device 2101-1 (step 2205).

  The wireless reception devices 406 of the slave stations 2103-1 and 2103-2 analyze the received packet and compare the slave station ID included in the packet with the own station ID. If the two match, the slave station activation information is output to the RCS control unit 303. On the other hand, if the slave station ID and the own station ID do not match, the slave station activation information is not output to the RCS control unit 303. In this case, the RCS control unit 303 maintains a state in which backscattering does not occur as much as possible with the rear surface of the corner reflector 301 facing the master station.

  FIG. 23 is an operation flowchart of the RCS control unit 303. The RCS control unit 303 checks whether or not the slave station activation information is input from the wireless reception device 406 (step 2301).

  When the slave station activation information is input, information of RCS fluctuation frequencies f1 Hz to f4 Hz corresponding to the ID “01” of the master station 2102-1 and the ID “11” of the slave station 2103-1 is generated, and the motor unit 302 receives the information. On the other hand, an instruction to rotate in the order of f1 Hz, f2 Hz, f3 Hz, and f4 Hz within X seconds is issued (step 2302). Accordingly, the corner reflector 301 rotates for X seconds while changing the frequency from f1 Hz to f4 Hz, reflects the electromagnetic wave 412 from the millimeter wave FMCW radar unit 403, and generates a backscattered wave.

  FIG. 24 shows an example of a radar ranging result when the slave station is activated. The reception level 2401 of the radio wave from the slave station is obtained by raising and lowering the threshold T3 at a frequency of f1 Hz to f4 Hz, and these frequencies are obtained by counting the number of times crossing the threshold T3.

  In this example, one reception level fluctuation frequency has 2-bit information, and f1 Hz, f2 Hz, f3 Hz, and f4 Hz represent “00”, “01”, “10”, and “11”, respectively. Yes. Among these, the bit string “0001” corresponding to the combination of f1 Hz and f2 Hz represents the ID “01” of the master station 2102-1, and the bit string “1011” corresponding to the combination of f3 Hz and f4 Hz is the slave station 2103-1. ID “11” is represented.

  When a Doppler shift frequency variable device is used instead of the RCS variable device, the configurations of the master stations 2102-1 and 2102-2 and the slave stations 2103-1 and 2103-2 are the same as those in the third embodiment. .

  In this case, the Doppler shift frequency control unit 1004 of the slave station 2103-1 generates information on four types of rotation frequencies corresponding to the ID “01” of the master station 2102-1 and the ID “11” of the slave station 2103-1. Then, the motor unit 1003 is instructed to rotate in order at those frequencies within X seconds. Thereby, the corner reflectors 1001-1 to 1001-4 rotate for X seconds while changing the frequency from f1 Hz to f4 Hz, and generate backscattered waves including four types of Doppler shift frequencies.

According to the seventh embodiment, it is possible to prevent erroneous detection of a slave station in an environment in which interference of radar waves from a plurality of master stations occurs.
FIG. 25 shows a position detection system according to the eighth embodiment. In this system, for example, the master station 2502 is installed on the ground and the slave station 2503 is installed on a moving object such as a vehicle in an environment where clutter from surrounding structures occurs. The configurations of the master station 2502 and the slave station 2503 are the same as those in the first embodiment.

  The position detection device 402 of the master station 2502 and the RCS control unit 303 of the slave station 2503 indicate a combination of a plurality of RCS fluctuation frequencies f1 Hz to fNHz and the state of the slave station (for example, a state in which the vehicle is preparing for advancement, running, etc.). A memory for storing a correspondence relationship with the slave station state information shown is provided.

  The position detection device 402 receives a slave station position detection instruction from the host device 2501 (for example, a control device of the system), issues a slave station activation information transmission instruction to the wireless transmission device 404, and a millimeter wave FMCW radar unit A measurement start instruction is issued to 403. However, unlike the first embodiment, the RCS fluctuation frequency information is not included in the slave station activation information.

  The wireless transmission device 404 generates a transmission packet including slave station activation information in accordance with an instruction from the position detection device 402, and transmits the packet. The millimeter wave FMCW radar unit 403 performs distance measurement for a preset time according to the measurement start instruction.

  An event control device 2504 is connected to the slave station 2503, and the event control device 2504 inputs slave station status information indicating the status of the slave station 2503 to the RCS control unit 303 of the slave station 2503.

  When the slave station activation information is input from the wireless reception device 406, the RCS control unit 303 collates the slave station state information input from the event control device 2504 with the slave station state information stored in advance in the memory. And the combination of the RCS fluctuation | variation frequency with which slave station state information corresponds is acquired from memory, and the corner reflector 301 is rotated with the combination of the frequency for the preset time.

  The position detection device 402 analyzes the distance measurement result input from the millimeter wave FMCW radar unit 403, and collates the combination of the reception level variation frequency of the target with the combination of the RCS variation frequency stored in advance in the memory.

  As a result, the slave station state information whose combination matches is acquired from the memory, and the relative distance value, the relative speed value, and the slave station state information of the target are output to the host device 2501. On the other hand, if a match with the combination of reception level fluctuation frequencies is not stored in the memory, information indicating that no slave station has been detected is output to the host device 2501.

  FIG. 26 shows an example of a radar ranging result when the slave station 2503 is activated. The reception level 2601 of the radio wave from the slave station 2503 increases and decreases the threshold value T4 at the frequency of f1 Hz in the first half of the distance measurement time, and increases and decreases the threshold value T4 at the frequency of f2 Hz in the second half. Those frequencies are obtained by counting the number of times of crossing the threshold T4. The slave station state information corresponding to the combination of these frequencies f1 Hz and f2 Hz is read from the memory, and is output to the host device 2501 together with the relative distance value and relative velocity value of the target.

According to the eighth embodiment, the master station can acquire information related to the status of the slave station in addition to the relative distance and relative speed of the slave station.
FIG. 27 shows a position detection system according to the ninth embodiment. In this system, an RCS variable device 2701 and an event control device 2702 are installed in a vehicle or the like instead of the slave station 2503 and the event control device 2504 in FIG. The configuration of the RCS variable device 2701 is the same as that of the first embodiment.

  When a specific event such as a vehicle accident occurs, the event control device 2702 inputs a combination of RCS fluctuation frequencies corresponding to the generated event to the RCS variable device 2701. Thereby, the RCS variable device 2701 rotates the corner reflector 301 with a combination of the frequencies for a preset time.

According to the ninth embodiment, for example, when a vehicle in which the master station 2502 is installed approaches the vehicle that caused the accident, the master station 2502 can grasp the position of the accident vehicle.
In the embodiment described above, the case where the millimeter wave FMCW radar is used has been described. However, as a radar that performs distance measurement, light, infrared rays, millimeter waves, microwaves, etc., as long as the radar can measure the reception level, Any electromagnetic wave may be used, and any method such as an FMCW method, a pulse method, a two-frequency method, or the like may be used in the radar method.

  By the way, as the RCS variable device installed in the slave station, various configurations other than those shown in FIGS. 2 and 3 can be considered. These configurations will be described with reference to FIGS.

  28 to 30 show a configuration for shielding the reflection surface of the corner reflector. Among these, FIG. 28 shows a configuration example of the flat plate rotation type RCS variable device. In this RCS variable device, a flat plate 2802 is provided in the vicinity of the opening surface of the corner reflector 2801, and the flat plate 2802 is rotated by the control / drive unit 2803 to vary the RCS. At this time, the projected opening area of the corner reflector 2801 changes depending on the orientation of the flat plate 2802. A radio wave absorber is attached to the rotating flat plate 2802 to prevent unnecessary reflection. The rotation axis 2804 of the flat plate 2802 is set to be parallel to the polarization plane of the incident wave.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of RCS fluctuation can be adjusted by changing the area of the flat plate 2802.
FIG. 29 shows a configuration example of a propeller-like flat plate rotation type RCS variable device. In this RCS variable device, a propeller-shaped flat plate 2902 is provided in the vicinity of the opening surface of the corner reflector 2901, and the flat plate 2902 is rotated by the control / drive unit 2903 to vary the RCS. At this time, the projected aperture area of the corner reflector 2901 changes depending on the rotation angle of the flat plate 2902. A radio wave absorber is attached to the rotating flat plate 2902 to prevent unnecessary reflection.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of fluctuation of the RCS can be adjusted by changing the shape and area of the flat plate 2902.
FIG. 30 shows a configuration example of the lattice disk rotating RCS variable device. In this RCS variable device, a lattice disk 3002 is provided in the vicinity of the opening surface of the corner reflector 3001, and the control / drive unit 3003 rotates the lattice disk 3002 to vary the RCS. At this time, the transmission amount of the radio wave / polarized wave changes depending on the rotation angle of the lattice disk 3002.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of fluctuation of the RCS changes depending on the angle of the lattice disk 3002.
31 and 32 show a configuration in which the effective area of the reflection surface of the corner reflector is changed. Among these, FIG. 31 shows a configuration example of the reflecting surface meniscus disk rotating RCS variable device. In this RCS variable device, a meniscus disk 3102 is attached to the reflecting surface of the corner reflector 3101, and the RCS is varied by rotating the meniscus disk 3102 by the control / drive unit 3103. The hatched portion of the half-moon disk 3102 is a cavity, and the remaining portion is a reflector. At this time, the projected area of the reflection surface of the corner reflector 3101 varies depending on the rotation angle of the half-moon disk 3102.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of fluctuation of the RCS changes depending on the angle of the half-moon disk 3102.
FIG. 32 shows a configuration example of the reflective surface vibration type RCS variable device. In this RCS variable device, the vibration unit 3202 is attached to the reflection surface of the corner reflector 3101, and the control unit / drive unit 3203 vibrates the vibration unit 3202 to vary the RCS. At this time, the phase synthesis in the reflection surface of the corner reflector 3101 changes due to the change in the vibration width of the vibration part 3202. The shape of the vibration unit 3202 is, for example, a disk shape, and its amplitude is, for example, about the wavelength of the incident wave.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of fluctuation of the RCS changes depending on the vibration width of the vibration unit 3202.
FIG. 33 shows a configuration example of a reflection surface angle change type RCS variable device that changes the angle of the reflection surface. In this RCS variable device, one reflecting surface 3302 constituting the corner reflector 3301 is attached so that the angle changes while the origin 3303 is fixed. Then, the control / drive unit 3203 changes the angle of the reflection surface 3302 to change the RCS. At this time, the incident angle and the reflection angle of the radio wave change due to the change in the angle of the reflection surface 3302.

According to this configuration, the RCS can be changed at a relatively high speed, and the amount of fluctuation of the RCS changes depending on the angle of the reflecting surface 3302.
FIG. 34 shows a configuration example of an array reflector type RCS variable device including a plurality (two or more) of corner reflectors. In this RCS variable device, a plurality of corner reflectors 3401 and 3402 are installed side by side vertically or horizontally. The control / driving unit 3203 moves the other corner reflector 3402 slightly up and down or left and right with the one corner reflector 3401 as a reference, thereby changing the RCS. At this time, the pattern width changes in the same manner as the array antenna due to a change in the distance between the reflectors. The movement width of the minute movement is, for example, about several wavelengths of the incident wave.

According to this configuration, the RCS can be changed at a relatively high speed, and the RCS changes according to a pattern obtained by combining the RCSs of a plurality of corner reflectors.
FIG. 35 shows a configuration example of the reflector tilt type RCS variable device. In this RCS variable device, the control / driving unit 3502 repeatedly rotates the reflector 3501 around the straight line 3512 passing through the midpoint 3511 of the side of the two-surface type reflector 3501 to vary the RCS. The reflector 3501 may be placed vertically or horizontally, and the reflector 3501 may be repeatedly vibrated around the straight line 3514 passing through the corner 3513 at the bottom. The rotation angle and vibration angle of the reflector 3501 are set to several degrees, for example.

According to this configuration, the RCS can be changed at a relatively high speed, and the RCS changes according to the RCS pattern in the narrow beam direction.
The RCS variable device shown in FIGS. 28 to 35 can rotate, vibrate, or move the reflector at the RCS fluctuation frequency instructed by the master station. According to these RCS variable devices, although there is a change in RCS, the reflected wave from the reflector does not become zero, so that there is an advantage that the reflected wave can be easily captured on the radar device side.

  FIG. 36 shows an example of a monitoring system using the various RCS variable devices described above. This system includes a sensor device 3601 such as a radar device and several RCS variable devices 3603-1 to 3603-3. The RCS variable devices 3603-1 to 3603-3 are installed in a monitoring range 3602 determined by the beam width of the antenna of the sensor device 3601, and are monitored by the sensor device 3601. At this time, in the monitoring range 3602, it is assumed that other reflectors 3604-1 to 3604-3 such as vehicles and people exist at the same distance as the RCS variable devices 3601-3 to 3603-3.

  In such a case, in the sensor device 3601, the reflected waves from the RCS variable devices 3603-1 to 3603-3 and the reflected waves from the reflectors 3604 to 1604-3 are combined. Since the reflected wave from the apparatus has the characteristic of RCS fluctuation, it can be clearly distinguished from other reflectors.

  According to such a system, it is possible to accurately find only a regular monitoring object within the monitoring range, and it is also possible to recognize the presence of a vehicle or a person within the monitoring range. Examples of application devices of this monitoring system include a detection sensor in a railroad crossing, a home faller detection sensor, a traffic counter, and various security sensors.

  The various RCS variable devices described above give application value or added value to all radar devices and communication devices that use reflectors such as corner reflectors. Note that it is possible to add a feature to the RCS fluctuation of the RCS variable device in the 76 GHz band in which the communication function is disabled in the millimeter wave band.

  Next, another configuration example of the Doppler shift frequency variable device installed in the slave station will be described. As the Doppler shift frequency variable device, other configurations than the rotary type shown in FIGS. 9 and 10 are conceivable.

  For example, the Doppler shift frequency component (frequency fluctuation) can be given to the reflected wave by linearly moving or vibrating the corner reflector in the distance direction with respect to the radar device or the like. At this time, by changing the period of movement or vibration of the corner reflector, the Doppler shift frequency of each Doppler shift frequency variable device can be changed, and each Doppler shift frequency variable device can be identified.

  FIG. 37 shows a configuration example of the first linear movement type Doppler shift frequency variable device. In this Doppler shift frequency variable device, the reflecting surface of the corner reflector 3701 is moved or vibrated back and forth in the distance direction.

  FIG. 38 shows a configuration example of the second linear movement type Doppler shift frequency variable device. In this Doppler shift frequency variable device, corner reflectors 3802-1 and 3802-2 are mounted on a roll type driving device 3803 having a slider function. Then, the roll type driving device 3803 is operated to move or vibrate the corner reflectors 3802-1 and 3802-2 back and forth in the distance direction with respect to the sensor device 3801 such as a radar device.

  37 and 38, the Doppler shift frequency can be added to the reflected wave for a certain time, and the level fluctuation of the reflected wave can be suppressed as compared with the rotary type. In the Doppler shift frequency variable device of FIG. 37, the device can be made smaller than the rotary type. On the other hand, in the Doppler shift frequency variable device of FIG. 38, the device is larger than that of the rotary type, but the moving range of the reflecting object is increased, so that the change of the Doppler shift frequency can be increased and the reflected wave can be easily identified. Become.

  FIG. 39 shows an example of a monitoring system using a rotary or linear movement type Doppler shift frequency variable device. This system includes a sensor device 3901 such as a radar device and a Doppler shift frequency variable device 3903. The Doppler shift frequency varying device 3903 is installed within the monitoring range 3902 determined by the beam width of the antenna of the sensor device 3901 and is monitored by the sensor device 3901. At this time, it is assumed that there is another reflector 3904 such as a vehicle or a person in the monitoring range 3902 at a distance equivalent to the Doppler shift frequency variable device 3903.

  In such a case, in the sensor device 3901, the reflected wave from the Doppler shift frequency variable device 3903 and the reflected wave from the reflector 3904 are combined, but the reflected wave from the Doppler shift frequency variable device 3903 is combined with the Doppler wave. Since the shift frequency is added, it can be clearly distinguished from other reflectors 3904. Further, even in a situation where there are many unnecessary reflected waves, the reflected waves from the Doppler shift frequency varying device 3903 can be reliably extracted.

  FIG. 40 shows an example of a road sign system using a rotary or linear movement type Doppler shift frequency variable device. In this system, a Doppler shift frequency variable device 4003 is installed around a road, and a moving object 4001 (a vehicle, a person, etc.) on which a sensor device 4002 such as a radar device is mounted (or carried) is displayed. Notify as information in advance. The Doppler shift frequency variable device 4003 is installed in the direction monitored by the sensor device 4002 on a road, for example.

  For example, when a lane restriction is imposed because construction is being performed in a specific range 4004, the Doppler shift frequency varying device 4003 adds a Doppler shift frequency component corresponding to the lane restriction to the reflected wave of the corner reflector. In the case of the rotary type, the corner reflector rotates in the direction and speed corresponding to the lane restriction, and in the case of the linear movement type, the corner reflector moves or vibrates in the direction and speed corresponding to the lane restriction. Mark data is generated by the Doppler shift frequency component of the wave.

  According to such a road sign, since radio waves are used, the sign data from the Doppler shift frequency variable device 4003 is received without being affected so much even in poor visibility due to bad weather or smoke. be able to.

  The various Doppler shift frequency variable devices described above give application value or added value to all radar devices and communication devices that use reflectors such as corner reflectors. For example, frequency modulation can be performed by adding or subtracting a Doppler shift frequency to the transmission frequency (carrier frequency) of the reflected radio wave.

  As a result, it is possible to identify the Doppler shift frequency variable device by adding features. Examples of the applied equipment include a frequency modulator using a reflector, a radio wave use sign by a reflector, and a simulation target for testing or evaluating a radar device.

  The position detection system using the reflection device such as the RCS variable device and the Doppler shift frequency variable device described above can be applied not only to the vehicle and the person but also to the position detection of other moving objects.

  For example, in the case of application to distance measurement at the time of ship berthing, a configuration in which a reflection device is installed at the tip of the ship and a radar device is installed at the quay is conceivable. If it is a ship, even if the structure of a reflection apparatus is a little large, it can be mounted.

In addition, when applied to cliff collapse monitoring, a configuration is conceivable in which reflection devices are scattered on the cliff surface and the movement and disappearance of these reflection devices are observed by a radar device.
For example, a plurality of reflectors are installed in a grid pattern on a cliff face, and only a first row of reflectors and then a second row of reflectors are used to specify a specific reflector from the radar device. Are operated in order, and the movement and disappearance of each reflector are observed. This makes it easy to observe local changes on a wide cliff.

(Appendix 1) A radar device that radiates electromagnetic waves, receives a reflected wave from a reflecting object, and detects the position of the reflecting object,
Transmitting means for transmitting activation information including information indicating a variation frequency of the reflection cross section to the reflection device that reflects the electromagnetic wave;
Radar means for radiating electromagnetic waves to the reflection device, receiving a reflected wave changing at the fluctuating frequency from the reflection device, and obtaining information on a relative distance from the reflected wave;
Analyzing a reception level of a plurality of received waves, extracting a reflected wave changing at the fluctuating frequency, and outputting a relative distance information obtained from the reflected wave as position information of the reflecting device; A radar apparatus comprising:
(Additional remark 2) It further has receiving means for receiving a response indicating that the activation information has been received from the reflecting device, and the position detecting means, when receiving the response, starts electromagnetic wave radiation to the radar means. The radar device according to appendix 1, wherein the radar device is instructed.
(Supplementary Note 3) The reception unit receives absolute position information from a plurality of reflection devices including the reflection device, and the position detection unit is obtained by the absolute position information of the plurality of reflection devices and the radar unit. The radar apparatus according to appendix 2, wherein the position of the radar apparatus is calculated from information on relative distances of the plurality of reflection apparatuses.
(Supplementary Note 4) The transmission means transmits the activation information including the identification information of the radar apparatus and the identification information of the reflection apparatus as information indicating the fluctuation frequency to the reflection apparatus, and the position detection means A reflected wave with a variation due to a fluctuation frequency corresponding to the identification information of the apparatus and a fluctuation frequency corresponding to the identification information of the reflection apparatus is extracted, and information on the relative distance obtained from the reflection wave is used as position information of the reflection apparatus The radar device according to appendix 1, which outputs the radar device.
(Supplementary Note 5) A radar device that radiates electromagnetic waves, receives a reflected wave from a reflector, and detects the position of the reflector,
Transmitting means for transmitting activation information including information indicating a Doppler shift frequency to the reflection device that reflects the electromagnetic wave;
Radar means for radiating electromagnetic waves to the reflecting device, receiving a reflected wave with a Doppler shift of the Doppler shift frequency from the reflecting device, and acquiring information on a relative distance from the reflected wave;
Position detecting means for analyzing signals of a plurality of received waves, extracting a reflected wave accompanied by a Doppler shift of the Doppler shift frequency, and outputting information on a relative distance obtained from the reflected wave as position information of the reflecting device A radar apparatus comprising:
(Supplementary Note 6) The transmission unit transmits the activation information including the identification information of the radar device and the identification information of the reflection device as information indicating the Doppler shift frequency, and the position detection unit includes A reflected wave accompanied by a Doppler shift frequency corresponding to the identification information of the radar apparatus and a Doppler shift frequency corresponding to the identification information of the reflecting apparatus is extracted, and information on the relative distance obtained from the reflected wave is extracted from the reflecting apparatus. The radar apparatus according to appendix 5, wherein the position information is output as position information.
(Appendix 7) Reflecting means for reflecting incident electromagnetic waves in the incident direction;
Receiving means for receiving activation information including information indicating the fluctuation frequency of the reflection cross section;
And a control means for changing a reflection sectional area of the reflection means at the fluctuation frequency.
(Additional remark 8) The said receiving means receives the said starting information containing the information which shows the said fluctuation frequency, and identification information, The said control means corresponds to the identification information of the said reflecting device in the identification information contained in this starting information The reflection device according to appendix 7, wherein the reflection sectional area of the reflection means is changed at the fluctuation frequency.
(Appendix 9) Reflecting means for reflecting incident electromagnetic waves in the incident direction;
Receiving means for receiving activation information including information indicating the Doppler shift frequency;
And a control means for controlling the operation of the reflecting means so as to generate a reflected wave accompanied by a Doppler shift at the Doppler shift frequency.
(Additional remark 10) The said receiving means receives the said starting information containing the information which shows the said Doppler shift frequency, and identification information, The said control means matches the identification information contained in this starting information with the identification information of the said reflection apparatus The reflection device according to appendix 9, wherein when the operation is performed, the operation of the reflection means is controlled so as to generate a reflected wave accompanied by a Doppler shift of the Doppler shift frequency.

1 is a principle diagram of a radar apparatus and a reflection apparatus of the present invention. It is an external view of an RCS variable device. It is a block diagram of a RCS variable apparatus. It is a block diagram of 1st Embodiment. It is an operation | movement flowchart of the position detection apparatus in 1st Embodiment. It is an operation | movement flowchart of the RCS control part in 1st Embodiment. It is a figure which shows the ranging result in 1st Embodiment. It is a block diagram of 2nd Embodiment. It is an external view of a Doppler shift frequency variable device. It is a block diagram of a Doppler shift frequency variable device. It is a block diagram of 3rd Embodiment. It is an operation | movement flowchart of the position detection apparatus in 3rd Embodiment. It is an operation | movement flowchart of the Doppler shift frequency control part in 3rd Embodiment. It is a figure which shows rotation operation | movement of a corner reflector. It is a figure which shows the ranging result in 3rd Embodiment. It is a block diagram of 4th Embodiment. It is a block diagram of 5th Embodiment. It is a block diagram of 6th Embodiment. It is a figure which shows the positional relationship of a mobile station and a fixed station. It is a figure which shows the ranging result in 6th Embodiment. It is a block diagram of 7th Embodiment. It is an operation | movement flowchart of the position detection apparatus in 7th Embodiment. It is an operation | movement flowchart of the RCS control part in 7th Embodiment. It is a figure which shows the ranging result in 7th Embodiment. It is a block diagram of 8th Embodiment. It is a figure which shows the ranging result in 8th Embodiment. It is a block diagram of 9th Embodiment. It is a block diagram of a plate rotation type RCS variable device. It is a block diagram of a propeller-shaped flat plate rotation type RCS variable device. It is a block diagram of a lattice disk rotation type RCS variable device. It is a block diagram of a reflective surface meniscus disk rotation type RCS variable device. It is a block diagram of a reflective surface vibration type RCS variable device. It is a block diagram of a reflective surface angle change type RCS variable device. It is a block diagram of an array reflector type RCS variable device. It is a block diagram of a reflector inclination type RCS variable device. It is a figure which shows a 1st monitoring system. It is a block diagram of the 1st linear movement type | mold Doppler shift frequency variable apparatus. It is a block diagram of the 2nd linear movement type | mold Doppler shift frequency variable apparatus. It is a figure which shows a 2nd monitoring system. It is a figure which shows a road sign system. It is a figure which shows a typical triangular corner reflector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Transmitting means 102 Radar means 103 Position detecting means 104 Reflecting means 105 Receiving means 106 Control means 201, 901 Housing part 202, 902 Radome 301, 1001-1, 1001-2, 1001-3, 1001-4, 2801, 2901, 3001, 3101, 3201, 3301, 3401, 3402, 3701, 3802-1, 3802-2 Corner reflector 302, 1003 Motor unit 303 RCS control unit 401, 1101, 2101-1, 2101-2, 2501 Host device 402, 1102 , 1701 Position detection device 403, 1103, 1702 Millimeter wave FMCW radar unit 404, 1104 Wireless transmission device 405, 1704, 2701 RCS variable device 406, 1106 Wireless reception device 407, 803, 1107, 16 03, 1706, 1803 Surrounding structure 411, 811, 1111, 1611, 1711, 1811 Clutter 412, 1112, 1712 Electromagnetic wave 701, 702, 1501, 1502, 2001, 2002, 2401, 2601 Reception level 711, 712, 1511, 1512 Relative distance value 721, 722, 1521, 1522 Relative speed value 801, 1601, 1801, 2102-1, 2102-2, 2502 Master station 802-1, 802-2, 802-N, 1602-1, 1602-2, 1602-N, 1802-1, 1802-2, 1802-N, 2103-1, 2103-2, 2503 Slave station 1002 Corner reflector rotation unit 1004 Doppler shift frequency control unit 1105, 4003 Doppler shift frequency variable device 1703, 17 05 Wireless communication device 2504, 2702 Event control device 2802 Flat plate 2803, 2903, 3003, 3103, 3203, 3304, 3403, 3502 Control / drive unit 2804 Rotating shaft 2902 Propeller plate 3002 Lattice disk 3102 Half moon disk 3202 Vibrating unit 3302 Reflecting surface 3303 Origin 3501 Two-surface type reflector 3511 Midpoint 3512, 3514 Straight line 3513 Angle 3601, 3801, 3901, 4002 Sensor device 3602, 3902 Monitoring range 3603-1, 3603-2, 3603-3, 3903 RCS variable device 3604-1 3604-2, 3604-3, 3904 Reflector 3803 Roll type driving device 4001 Moving object 4004 Range

Claims (4)

A radar device that radiates electromagnetic waves, receives a reflected wave from a reflector, and detects the position of the reflector,
Transmitting means for transmitting activation information including information indicating a variation frequency of the reflection cross section to the reflection device that reflects the electromagnetic wave;
Radar means for radiating electromagnetic waves to the reflection device, receiving a reflected wave changing at the fluctuating frequency from the reflection device, and obtaining information on a relative distance from the reflected wave;
Analyzing a reception level of a plurality of received waves, extracting a reflected wave changing at the fluctuating frequency, and outputting a relative distance information obtained from the reflected wave as position information of the reflecting device; A radar apparatus comprising: A radar device that radiates electromagnetic waves, receives a reflected wave from a reflector, and detects the position of the reflector,
Transmitting means for transmitting activation information including information indicating a Doppler shift frequency to the reflection device that reflects the electromagnetic wave;
Radar means for radiating electromagnetic waves to the reflecting device, receiving a reflected wave with a Doppler shift of the Doppler shift frequency from the reflecting device, and acquiring information on a relative distance from the reflected wave;
Position detecting means for analyzing signals of a plurality of received waves, extracting a reflected wave accompanied by a Doppler shift of the Doppler shift frequency, and outputting information on a relative distance obtained from the reflected wave as position information of the reflecting device A radar apparatus comprising: Reflection means for reflecting incident electromagnetic waves in the incident direction;
Receiving means for receiving activation information including information indicating the fluctuation frequency of the reflection cross section;
And a control means for changing a reflection sectional area of the reflection means at the fluctuation frequency. Reflection means for reflecting incident electromagnetic waves in the incident direction;
Receiving means for receiving activation information including information indicating the Doppler shift frequency;
And a control means for controlling the operation of the reflecting means so as to generate a reflected wave accompanied by a Doppler shift at the Doppler shift frequency.