KR20000072786A - Local Positioning System. - Google Patents

Abstract

PURPOSE: A local positioning system is provided to simplify a structure so as to miniature a terminal and to acknowledge positions of terminals in real time. CONSTITUTION: A local positioning system comprises a central control unit, a plurality of transmission base stations, a plurality of receive base stations, a plurality of terminals. The receive base stations are arranged so as to be connected in common to each of the base stations. The central control unit synthetically controls the transmission base stations and calculates a position. The terminals moves in a transmission and reception coverage of a receive base station related to the transmission base station.

Description

Local Positioning System.

The present invention relates to a short-range location tracking system, and more particularly, to the synchronized base stations fixedly fixed within a certain location tracking range, a central control unit for controlling them, and to periodically transmit a code signal while moving within the location tracking range. The present invention relates to a system composed of terminals, wherein each base station calculates a delay time of a signal transmitted by the terminals and displays the position of the terminal on a map of the central control unit monitor by a triangulation method.

Although a variety of methods have been introduced for the location tracking technology, a system for precisely tracking the location at a short distance using a small low cost terminal has not yet been introduced.

Global Positioning System (GPS), a global positioning system, has a merit of being able to know its position anywhere on the earth as a reception-only terminal. However, there is a disadvantage in that a separate wireless data transmission means must be provided when the central controller wants to know the location of terminals moving within a predetermined range. The location tracking error is also suitable for a vehicle moving in a wide range, but is not suitable for tracking the position of a person moving in a narrow range of a radius of several kilometers within a few meters of error. In addition, the miniaturization and low power consumption of the terminal are rapidly progressing, but the portability, size, and power consumption are not guaranteed yet.

In order to solve the above problems, the present invention proposes a new short-range location tracking system focused on miniaturization, low cost (simple), low power consumption, and improved position tracking accuracy.

First of all, in order to simplify the structure of the terminal, the present invention has a feature that the terminal only needs to repeatedly transmit a predetermined signal at a predetermined time slot with a location calculation function at the base station. At this time, it is necessary to receive the synchronization signal transmitted from the base station in order to achieve synchronization, which is also simplified to a structure that receives the synchronization signal at a time determined by a time division duplex (TDD) scheme and synchronizes the wrong terminal.

In addition, in order to minimize the power consumption of the terminal, the present invention separates the transmitter station and the receiver station so that multiple receiver stations are distributed per transmitter station so that the terminal can be received even if the output power of the terminal is small. Therefore, the transmission signal is transmitted only at its own time slot so that most of the time it does not transmit has little power consumption.

As such, since the terminal is simplified and power consumption is reduced, the terminal of the short-range location tracking system of the present invention can be one chip sufficiently even with the current semiconductor technology, and the overall size can be reduced to about a wrist watch. have. The cost of manufacturing is also very low, allowing mass production with almost one-time consumables.

In terms of positioning accuracy, the position tracking system of the present invention uses a direct sequence wideband spread spectrum technique, which uses a bandwidth of 50 MHz, although the error varies depending on the bandwidth. When the clock frequency of the correlator is 100 MHz, an error of less than 3 m can be realized. If you use a bandwidth of 100MHz and set the clock frequency to 200MHz, the error is reduced to within 1.5m.

Due to the above characteristics of the present invention, its application range is very diverse as follows.

(1) Amusement Park Visitor Positioning System

(2) Location tracking system for important facilities

(3) Amusement Park, Stadium Missing Prevention System

(4) Golf Course Customer Location Tracking System

(5) Wharf freight container positioning system

(6) Product location tracking system in the factory

(7) Material and personnel location tracking system in construction site

1 is a conceptual diagram of a conventional global positioning system (GPS)

2 is an overall configuration of the short-range location tracking system of the present invention

3 is a conceptual diagram of a short-range location tracking system of the present invention

4 is a conceptual diagram of location tracking of the present invention

5 is a configuration diagram of an embodiment of a transmitter station of the present invention.

6 is a block diagram of an embodiment of a receiver station of the present invention.

7 is a configuration diagram of an embodiment of a central control device of the present invention;

8 is a configuration diagram of an embodiment of a terminal of the present invention

9 is a timing diagram of a signal of the short-range location tracking system of the present invention.

<Description of the symbols for the main parts of the drawings>

202: central control unit 203: transmitter station

204: receiver station 205: terminal

501: Terminal synchronization signal generation 512: Receiver station synchronization signal generation

610, 813: PN code generator 608: Delay time detection

701: synchronization signal generation circuit 808: synchronization signal detection

Hereinafter, the present invention and its embodiments will be described in detail with reference to the accompanying drawings.

1 shows a conceptual diagram of a conventional global positioning system (GPS). GPS is a useful method when you want to know its position at any point on the earth. It receives the signal transmitted from the satellites 101, 102, 103 and uses the delay time to determine the location point 104 by triangulation method. ) Latitude, longitude, and altitude. In other words, the position of the positioning point is the intersection point of the sphere whose radius is the distance from the satellite. However, this method is useful when the terminal wants to know its location, and when the terminal wants to know the locations of the scattered terminals, a separate communication means for transmitting its location to the central control device is required. In addition, if the position measurement error is very large, dozens or hundreds of meters, it is difficult to apply when more precision is required, and there is a limit in miniaturization due to problems such as size, price, power consumption of the terminal.

Accordingly, the present invention proposes a new location tracking system capable of real-time tracking of the location of a person or an object carrying a micro terminal in a short distance of several kilometers in a few meters error.

2 is an overall configuration diagram of the short-range location tracking system of the present invention.

As shown in the figure, the short-range position tracking system of the present invention bundles one or more transmitter stations 203, a plurality of receiver stations 204 and one transmitter station 203 connected to one transmitter station 203. The central control unit 202 for controlling the entire system and performing position calculation, and the plurality of terminals 205 moving in the transmission / reception range 201 of the transmitter station 203 and the receiver station 204 accompanying it. Consists of

The concept of the short-range location tracking system of the present invention based on FIG. 3 will be described in detail.

If only one transmitter station 303 and one receiver station 304 connected thereto of one of the transmitter stations connected to the central control unit 302 are described,

The transmitter station 303, the receiver station 304, and the terminal 305 located within the predetermined position tracking range 301 are all synchronized with the central control unit 302. The method is, firstly, the central control unit 302. ) Transmits the synchronization signal to the transmitter base station 303 (306), and the transmitter station 303 transmits it to the receiver station 304 by wire or wireless means (309), and simultaneously converts the terminal into a terminal synchronization signal Wirelessly transmit 307 to 305.

After receiving the synchronization signal, the terminal 305 corrects its synchronization and transmits a PN code (pseudo noise) indicating its location to a time slot corresponding to its own ID. Three or more receiver stations 304 receiving the PN code detect a delay time of the PN code transmitted from the terminal 305 with a correlator, and transmit this information to the transmitter station 303 (309). The transmitter station 303 transmits it back to the central control unit 302 (306).

In the central control unit 302 calculates the distance of the terminal using the delay time (distance) information between each terminal from the transmitter station 303, and the receiver station 304 receiving the transmission signal of the terminal, This is displayed on the map of the screen.

4 is a conceptual view illustrating the location tracking of the present invention, in which the central control unit 302 uses the propagation delay times T1, T2, and T3 from the terminal 405 to the three receiver stations 401, 402, and 403. A method of calculating the position of the terminal 405 is shown. When a circle is drawn based on the propagation delay times T1, T2, and T3 from the terminal 405 to each of the receiver stations 401, 402, and 403 by the triangulation method, the intersection is the position of the terminal 405. .

However, when the circles intersect at one point, the synchronization between the terminal 405 and the receiver stations 401, 402, and 403 is perfectly matched, and in reality, the circles cross at one point because the synchronization is slightly different. As shown in FIG. 4 without overlapping, or opposite to each other, they do not cross each other. However, even in this case, the synchronization error between the terminal and the receiver stations is the same as all three receiver stations 401, 402, and 403 are the same, and thus the position of the actual terminal 405 is the same distance from the drawn circles in the normal direction.

5 is a block diagram of an embodiment of a short-range location tracking system transmitter station of the present invention.

The role of the transmitter station can be divided into two main roles. The first is to transmit the synchronization signal received from the central control unit to the receiver station and the terminal to synchronize the entire system, and the second is to transmit the distance information from the receiver station to the terminal to the central controller.

The operation will be described in detail with reference to the drawings.

A synchronization signal is received from the central controller through the synchronization signal receiving unit 507, the terminal synchronization signal generation unit 501 converts it to a terminal synchronization signal, modulates it in the modulator 502, and generates the local oscillator 508. The signal is mixed 503 with the local oscillation signal, amplified 504, filtered 505 and transmitted to the terminal via the antenna 506. Meanwhile, in order to send the synchronization signal received from the central controller to the receiver stations, the synchronization signal converted by the receiver station synchronization signal generator 512 is transmitted to the receiver stations by wire or wireless transmission means. In addition, the information from the receiver stations is converted by the serial data conversion circuit 511 to send to the central control unit via the serial communication unit 509, and then sent back to the central control unit via the serial communication unit 510.

6 is a block diagram of an embodiment of a short-range location tracking system receiver station of the present invention.

The receiver station measures the delay of the PN code transmitted from the terminal in accordance with the overall system synchronization and transmits the delay to the transmitter station.

This will be described in detail with reference to the drawings as follows.

The terminal signal received through the antenna 601 is mixed with the local oscillator 609 signal in the mixer 604 through the filter 602 and the low noise amplifier 603 and converted into an intermediate frequency, which is again converted into the filter 605. The demodulator 607 is demodulated via the amplifier 606 and input to the delay time detection circuit 608. On the other hand, the synchronization signal received from the transmitter station is processed by the synchronization signal receiver 611 to enter the PN code generator 610 to synchronize the PN code, and the generated PN code is delayed together with the demodulated terminal signal. In the detection 608 circuit, the delay time is calculated and input to the microprocessor 613 in a correlation detection scheme. The microprocessor 613 calculates the distance to the terminal based on the delay time, and then attaches the terminal ID according to the time slot of the terminal signal and the ID of the receiver station itself. Transmit to transmitter station via. The transmitter station transmits this information to the central control unit as it is, and the central control unit calculates the position of the terminal by synthesizing the distance information between the receiver station and the terminal from all receiver stations.

7 is a configuration diagram of an embodiment of a central control device of the present invention.

The role of the central controller is to generate and transmit a synchronization signal to synchronize the whole system to the transmitter station, and calculate the position of the terminal by synthesizing the distance information between the terminal and the receiver station coming from the receiver stations through the transmitter station. To display. First, the synchronization signal is generated in the synchronization signal generation circuit 701 and transmitted to each transmitter station, and information coming from the transmitter stations is transmitted through the serial communication circuits 702, 703, and 704 in the distance calculation circuit 705. The distance is comprehensively calculated and sent to the PC 706. The PC 706 uses this information to connect with its own map data and display the location of the terminals on the map for the user to recognize at a glance.

8 is a configuration diagram of an embodiment of a terminal of the present invention.

The terminal synchronizes with the synchronization signal transmitted from the transmitter station, and transmits a predetermined PN code at its time slot to allow nearby receiver stations to calculate the distance. The process is described below based on the drawings.

First, in order to receive the synchronization signal, the terminal switches to the reception state, receives the signal, and checks whether the synchronization signal is detected. Looking at the signal path at this time, the signal received by the antenna 801 is passed through the filter 802, the low noise amplifier 803, the mixer 804, the intermediate frequency filter through the wireless switch 809 switched to the reception state ( 805, and then in the order of the intermediate frequency amplifier 806, it is demodulated by the demodulator 807, and then the presence or absence of a synchronization signal is detected by the synchronization signal detection circuit 808. At this time, once the synchronization signal is detected, in order to reduce power consumption of the terminal thereafter, power is supplied to the receiver to receive the synchronization signal only when the next signal reception expected period is approaching, and the power is not supplied to the receiver at other times. Do not. If the synchronization signal detection fails even when the synchronization signal reception is expected, the process of detecting the synchronization signal is started again.

The detected synchronization signal is transmitted to the PN code generator 813 and the microprocessor 814 to determine the time slot for the terminal to transmit the PN code and to turn on / off the power of the transceiver. Used to manage Looking at the signal path through which the terminal transmits the PN code, the PN code generator (PN code generator) based on the unique ID information for each terminal, which is held in the terminal ID memory 815 itself and the synchronization signal output from the synchronization signal detection circuit 808, is used. 813 determines a time slot to transmit a PN code to generate a PN code, which is mixed with the output of the local oscillator 810 in a mixer and converted into a radio carrier signal, followed by a power amplifier 811, The radio switch 809 is transmitted to the antenna 801 via the filter 802. In this case, in order to minimize power consumption of the terminal, power is not normally supplied to the transmission unit including the power amplifier 811, but only power is supplied for a time for transmitting the PN code.

9 is a timing diagram of a signal of the short-range position tracking system according to the present invention. The timing of the detailed signal from the central controller to the terminal and the process of calculating the position of the terminal based on the same will be described with reference to the following drawings. do.

The synchronization signal 901 transmitted from the central control unit arrives 902 at the transmitter station with some time delay T1. The transmitter station transmits this synchronization signal to the receiver stations, where the times at which the receiver stations receive the synchronization signals (903, 904, 905) all depend on the distance between the transmitter station and the receiver station (T2, T3, T4). . The transmitter station simultaneously transmits this synchronization signal to the terminals 906, with a slight delay T5 in processing and transmitting the terminal synchronization signal. Also, the delay time T [x] until the terminal receives the synchronous signal 907 is different for each terminal according to the distance from the transmitter station to the terminal. When the synchronization is readjusted according to the received synchronization signal and the transmission time (Time Slot, T6) is reached, the PN code is transmitted (908), and these signals have different delay times (T [a] and T [b). ], After reaching T [c]), it reaches the receiver station (909, 910, 911).

At this time, the time from T1 to T6 of each delay time is the delay time between the fixed central control unit, the transmitter station and the receiver station, so it can be known in advance by measurement. T [x], T [a], T Only [b] and T [c] will remain variables.

If the three equations including these variables are calculated in the manner shown in Fig. 4, the position of the terminal is accurately calculated.

At this time, the position measurement resolution (error) is different depending on the clock frequency used for correlation detection at the receiver station, which is 3m using 100MHz and 1.5m using 200MHz.

As described above, the present invention,

It consists of transmitting and receiving base stations installed in various locations within the location to be tracked, a central control unit for controlling them, and a large number of small terminals moving in the location to be tracked, so that the central controller can know the location of the terminals in real time. In organizing,

To simplify the construction of the terminal, the structure is simplified,

In order to minimize the power consumption, a plurality of receiver stations are installed in one transmitter station so that the transmission power of the terminal may be small. Most of the time slots do not transmit by transmitting transmission signals only at their own time slots. There is little power consumption in time,

In order to improve the location tracking accuracy, wideband ranging technique is used.

Claims (3)

In a near-location tracking system, One or more transmitter station 203, A plurality of receiver stations 204 connected to one transmitter station 203, A central control unit 202 for tying the transmitter stations 203 to control the entire system and to perform position calculation, And a plurality of terminals 205 moving within a transmission / reception range (Coverage) 201 of the transmitter station 203 and the receiver station 204 attached thereto. In the location tracking method, Transmitting, by the central controller 302, a synchronization signal to the transmitter station in order for the central controller 302 and the transmitter station 303, the receiver station 304 and the terminal 305 to synchronize, Transmitting (309, 307) the transmitter station 303 receiving the synchronization signal to the receiver station 303 and the terminal 305; Transmitting, by the terminal receiving the synchronization signal, a PN code at a transmission time determined according to its unique ID (308); Calculating a distance from the receiver to the terminal by receiving a PN code by a correlation detection method; Transmitting the ID of the terminal and the receiver station ID to the transmitter base station 303 in the calculation result; Transmitting, by the transmitter station 303, the information received from the receiver stations 303 to the central control unit 302, And calculating, by the central controller (302), the location of the terminal by combining the distance information received from the transmitter stations (303). The method of claim 1, In order to simplify the structure of the terminal to facilitate miniaturization, It simply transmits the PN code but does not have complicated functions such as position calculation. By time division duplex (Time Division Duplex) method to use the same transmission and reception frequency, In order to minimize power consumption, By reducing the transmission power of the terminal by receiving the terminal signal through a plurality of receiver stations 204 attached to one transmitter station 203, By the time division multiple access (Time Division Multiple Access) method, the terminal powers on only its own time slot and transmits a signal. And receiving a synchronization signal periodically transmitted from a transmitter station, the function of supplying power to the receiver only before and after the expected synchronization signal reception time to receive the synchronization signal.