JPH09287908A - Method and system for measuring position on road and apparatus suitable for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always measure a correct position on a moving body. SOLUTION: A plurality of leaked cables 12 are arranged parallel along a road, and transmitters 10 adjacent to each other transmit pulse signals for measuring distance to the corresponding leaked cables 12 synchronizing each other and at timings different from each other. A measuring device 16 is carried on a moving object such as vehicle 14 running on the road and receives a leaked radiation of the pulse signal for the measurement from the leaked cables 12. Since the pulse signal for measuring the distance received by the measuring device 16 reflects the required transmission time for propagation on the leaked cables 12 and the difference therebetween in addition to a difference in transmission time between the transmitters 10, if the interval D between the transmitters 10 is known in advance, the relative position L of the vehicle 14 can be known. Identification information of the transmitters 10 is transmitted through the leaked cables 12 from the transmitters 10, thereby enabling the absolute position thereof to be known as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road position measuring method and system for measuring the position of a moving body such as a vehicle running on a road on the moving body, and an apparatus suitable for these.

[0002]

2. Description of the Related Art As means for measuring the position of a vehicle on a road on the vehicle,
Conventionally, means for utilizing signals transmitted from navigation satellites such as GPS (Global Positioning System) receivers and means for accumulating information obtained from vehicle-mounted acceleration sensors, speed sensors, direction sensors, etc. have been used. There is. However, the former has a problem that the measurement cannot be performed outside the view range of the navigation satellite (in the tunnel or under the overpass), and the latter has a problem that the error is accumulated due to the integration and the accurate measurement cannot be performed. ing. In order to solve these problems, in-vehicle measuring instruments that combine both means and map matching have already been put into practical use, but different measurement results can be obtained depending on the combination method, and the processing is generally complicated. There are still some problems, such as the tendency to become.

One of the objects of the present invention is to make use of the leak cable technology, regardless of the traveling environment such as in a tunnel or not, and the state of the moving body such as traveling distance up to now. Instead, it is intended to always obtain accurate measurement results. One of the objects of the present invention is to make it possible to obtain a stable measurement result by relatively simple signal processing by devising a laying mode of a leaky cable and a transmission method using this leaky cable. Especially. One of the objects of the present invention is to devise the content of the signal to be transmitted so that not only the relative position of the moving body (for example, the position with respect to the nearest transmitter) but also the absolute position (with respect to a predetermined reference point, for example, a specific transmitter). Position).

[0004]

In order to achieve such an object, the road position measuring method according to the first configuration of the present invention is for measuring the position of a moving body traveling on a road. In advance, a plurality of leaky cables are laid along the extension direction of the road so as to at least partially overlap with any other leaky cable, and at least one is transmitted for each leaky cable. In order to measure the position, the transmitter transmits the pulse signals for distance measurement in synchronization with each other on the corresponding leaky cable and at a predetermined time difference, so that the leaky cable on the road. Distance measurement pulse signal is radiated and radiated from the plurality of leakage cables while the loading measuring device mounted on the moving body is radiated and radiated from the plurality of leakage cables. Wirelessly receiving the signal and measuring the relative position of the moving body with respect to the leaky cable or the transmitter along the extension direction of the road based on the reception interval of the distance measurement pulse signal, the interval of the transmitter and the predetermined time difference. Is characterized by.

In this configuration, the distance measuring pulse signal leaking and radiating from the leaking cable is wirelessly received by the load measuring device, and the result is used to measure the position of the moving body. That is, the reception interval of the series of distance measuring pulse signals received by the load measuring device is mainly due to the distance measuring pulse signal transmission time difference between transmitters and the distance measuring pulse signal propagating on the leakage cable. It is determined by the time required, and the latter, that is, the propagation time, is mainly determined by the distance from the transmitter to the moving body and the distance between the transmitters.Therefore, the reception interval of the distance measurement pulse signal, the distance between the transmitters, and the distance between the transmitters. The distance from the transmitter to the moving body, that is, the relative position of the moving body can be known by knowing the time difference of the distance measurement pulse signal transmission. In this configuration, since the relative position of the moving body is measured based on the principle of utilizing the signal propagation delay on the leaky cable in this way, regardless of the traveling environment such as whether or not the moving body is in the tunnel, In addition, accurate measurement results can always be obtained regardless of the state of the moving body such as the traveling distance up to now. Further, the relative position detection logic based on the above principle can be expressed by a simple mathematical expression or the like. That is, in the present configuration, complicated signal processing or calculation is unnecessary, and its implementation is easy.

Further, a road position measuring method according to a second configuration of the present invention is the same as the road position measuring method according to the first configuration, wherein the transmitter identifies the transmitter identifying information unique to the transmitter. By transmitting the pulse signal for use, after or in advance of the pulse signal for distance measurement, onto the corresponding leaky cable, the pulse signal for transmitter identification is leaked and radiated from the leaky cable onto the road, and The moving body
Wirelessly receives a transmitter identification pulse signal radiated and radiated from the plurality of leakage cables, and measures the absolute position of the moving body based on the identification information and the relative position extracted from the transmitter identification pulse signal. It is characterized by doing. In this way, by transmitting and receiving the identification information, it becomes possible to detect the position of the transmitter in the load measuring device, and by combining this with the relative position obtained by the above-mentioned principle, it is possible to measure the absolute position. Become.

The roadside equipment according to the third aspect of the present invention includes a plurality of leaky cables provided along the extension direction of the road and at least partially overlapping with any other leaky cable. At least one is provided for each leaky cable, and by sending distance measurement pulse signals to the corresponding leaky cables in synchronization with each other and with a predetermined time difference, the leaky cable is used for distance measurement on the road. And a transmitter that leaks and radiates a pulse signal. Further, the load measuring device according to the fourth configuration of the present invention is a means for wirelessly receiving distance measurement pulse signals leaking and radiating from the plurality of leaky cables included in the roadside equipment according to the third configuration. , The relative distance of the moving body to the leaky cable or transmitter along the extension direction of the road based on the reception interval of the distance measurement pulse signals leaked and radiated from different leaky cables, the interval between the transmitters and the predetermined time difference. Means for measuring the position, and is mounted on a moving body traveling on the road. According to these configurations, the roadside equipment and the load measuring device suitable for implementing the first configuration can be obtained.

The on-road position measuring system according to the fifth aspect of the present invention has the roadside equipment according to the third aspect and the load measuring device according to the fourth aspect, and the transmitter is for the roadside equipment. The plurality of leaky cables are arranged along the extension direction so as to be spaced from each other at predetermined intervals, and are laid so as to extend symmetrically in the upstream direction and the downstream direction of the road when viewed from the corresponding transmitter. The measuring device executes the road position measuring method according to the first or second configuration. With this configuration, it is possible to realize a system that exhibits the same effect as the first or second configuration. Furthermore, since the leaky cables are symmetrically extended in the upstream and downstream, the number of leaky cables and transmitters can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a road position measuring system according to an embodiment of the present invention. In this system, a plurality of transmitters 10 are arranged at predetermined intervals D along the extension direction of the road. Each transmitter 10 has a corresponding leaky cable (eg leaky coaxial cable; LC
X) send a pulse signal on 12. Leakage cable 12
Respectively extend by D on the upstream side and the downstream side of the road as viewed from the corresponding transmitter 10, and thus the leakage cable 1
The length of 2 can be represented by 2D. However, with respect to the most upstream leakage cable 12 and the most downstream leakage cable 12 in FIG. 1, the cable length is D because it extends only to one of the upstream and downstream sides.

Further, in this system, the measuring device 16 is mounted on the vehicle 14 traveling on the road. The measuring device 16 has the functional configuration shown in FIG. In FIG. 2, an antenna 18 and a receiver 20 for receiving a signal leaked and radiated from the leaky cable 12 are provided. The output of the receiver 20 is supplied to the reception time difference counting section 22 and the transmitter identifying section 24. Reception time difference counting unit 2
2 counts a reception time difference (reception interval) of a distance measurement pulse signal, which will be described later, among signals received by the receiver 20, and supplies the result to the relative position calculation unit 26. The relative position calculation unit 26 calculates the relative position of the vehicle 14 to be mounted, that is, the distance to the nearest transmitter 10, based on the reception time difference counted by the reception time difference counting unit 22,
The result is supplied to the absolute position calculation unit 28 or the output unit 30 as indicated by the broken line in the figure.

On the other hand, the transmitter identifying section 24 decodes a pulse signal for identifying a communication device, which will be described later, among the signals received by the receiver 20, and identifies which transmitter is the transmitter 10 which has transmitted the signal. . The identification result by the transmitter identification unit 24 is supplied to the transmitter position calculation unit 32, and the transmitter position calculation unit 32 calculates the position of the transmitter 10 based on this. The absolute position calculation unit 28, based on the relative position supplied from the relative position calculation unit 26 as described above and the position of the transmitter 10 calculated by the transmitter position calculation unit 32,
The absolute position of the vehicle 14 to be mounted, for example, the position based on a certain specific transmitter 10, that is, the specific transmitter 10
Calculate the distance traveled from the position. The output unit 30 outputs the absolute position or the traveled distance obtained by the absolute position calculation unit 28 as a character image or voice, or outputs the relative position obtained by the relative position calculation unit 26 in the same manner. The traveling direction determination unit 34 identifies the calculation formula to be used by the relative position calculation unit 26 by monitoring the information obtained by the transmitter identification unit 24 in time series.

FIG. 3 shows the principle of position measurement in this embodiment. In particular, what is shown in FIG. 3A is a signal transmission timing by each transmitter 10. As shown in this figure, each transmitter 10 repeats a predetermined transmission operation in units of a predetermined measurement cycle T. Further, within this measurement period T, a distance measurement is performed in which the distance measurement pulse signal is repeatedly transmitted a total of P times at a pulse repetition period Tr (Tr> D / C, where C is the signal propagation speed on the leaky cable 12). The period and the distance measurement period are followed by a transmitter identification period for transmitting a transmitter identification pulse signal.

During the distance measurement period, FIG.
A pulse signal for distance measurement is transmitted from each transmitter 10 in a format as shown in (b). That is, two transmitters 1 adjacent to the inner phase of the plurality of transmitters 10 shown in FIG.
0 is a predetermined pulse transmission time difference Td (Tr-D / C>Td> after one of them transmits the distance measurement pulse signal).
The distance measurement pulse signal is transmitted to the corresponding leaky cable 12 in such a procedure that the other one transmits the distance measurement pulse signal when D / C) has passed. When the distance measuring pulse signal is transmitted to the leaky cable 12 at such timing, the measuring instrument 16 receives the distance measuring pulse signal at the timing shown in FIG. That is, the distance measuring pulse signal transmitted from one transmitter 10 is received by the measuring device 16 after TL1 has elapsed from the transmission onto the corresponding leaky cable 12, and the other leaky cable 12 is transmitted by the other transmitter 10. The transmitted distance measuring pulse signal above is received by the measuring device 16 after TL2 has elapsed from this transmission. The reception delays TL1 and TL2 are mainly caused by the propagation of the distance measurement pulse signal on the leaky cable 12. Therefore, assuming that the vehicle 14 is now at the position of the distance L (D ≧ L ≧ 0) when viewed from the transmitter 10 on the downstream side, the reception delays TL1 and TL2 are

## EQU1 ## TL1 = L / C TL2 = (D−L) / C As a specific numerical example, D = 50
Assuming 0 m and C = 3 × 10 ⁸ m / s, T = 1 m
Combinations of s, Tr = 10 μs, Td = 3 ms, P = 50, etc. can be listed.

As described above, since the reception delays TL1 and TL2 are caused mainly by the propagation delay on the leaky cable 12, the reception interval of the distance measuring pulse signal in the measuring device 16 is

[Equation 2] t = Td−TL1 + TL2 t ′ = Tr−t = Tr−Td + TL1−TL2 (see FIG. 3C). The reception time difference counting unit 22 counts the time differences t and t ′,
It is given to the relative position calculation unit 26. The relative position calculation unit 26
The distance L, that is, the relative position is obtained based on the time difference t or t '. When calculating L, the calculation formula differs depending on whether t or t ′ is used. That is, t
When using

## EQU00003 ## When using the equation of L = (D-C.t + C.Td) / 2 and t ',

## EQU00004 ## The equation L = (D + C.t'-C.Tr + CTd) / 2 should be used respectively. The relative position calculation unit 26 refers to the output of the traveling direction determination unit 34 in order to determine which formula is used. That is, the traveling direction determination unit 34 utilizes the transmitter identification result obtained from the transmitter identification unit 24 according to the above-described principle, and when the vehicle 14 passes the position of the transmitter 10, the traveling direction of the vehicle 14 is advanced. Detect direction. The relative position calculation unit 26 uses the output of the traveling direction determination unit 34 to determine whether it is t or t ′ that is obtained by the reception time difference counting unit 22, and according to the result, the above two equations are used. Adopt one of them.

In the transmitter identification period shown in FIG. 3A, the transmitter 10 on the downstream side transmits a pulse signal for transmitter identification and the transmitter 10 on the upstream side identifies the transmitter. It is divided into a period for transmitting a pulse signal for use. The repetition cycle of the transmitter identification pulse signal can also be the same cycle as that of Tr in the distance measurement pulse signal, that is, Tr. The transmitter identifying pulse signal is a signal for identifying which transmitter 10 the transmitting transmitter 10 is, that is, a signal carrying identification information. This identification information must be coded so that the transmitters 10 shown in FIG. 1 can be individually distinguished. For example, if there are N transmitters 10 in total and the identification information is generated by binary encoding, the number of bits M required to express the identification information is

Since M ≧ log ₂ N, the maximum number of transmitter identifying pulse signals is M
Becomes As a numerical example, when N = 1000, since log ₂ 1024 = 10, a numerical value of M = 10 can be set as a preferable value.

The transmitter identifying unit 24 described above decodes the transmitter identifying pulse signal to extract identification information for identifying which of the transmitters on the downstream side and the upstream side, and extracts it. Is supplied to the transmitter position calculation unit 32 and the traveling direction determination unit 34. The traveling direction determination unit 34 monitors the identification information in time series as described above,
The traveling direction of the vehicle 14 is determined. On the other hand, the transmitter position calculation unit 32 converts this identification information into the position of the transmitter 10 involved in communication. In this communication, for example, a table in which the identification information and the position coordinates of the transmitter 10 are associated with each other may be used, or the identification information may indicate in advance the distance of the transmitter 10 from the start point along the extension direction of the road. If it is set as shown, the position of the transmitter 10 may be obtained by algebraic calculation based on the identification information. The absolute position calculation unit 28 adds the position of the transmitter 10 thus obtained and the relative position obtained by the relative position calculation unit 26 as described above, and thereby obtains the absolute position.

As described above, according to the present embodiment, the leakage cable 12 is attached along the road, and the leakage cable 1 is attached.
The measuring device 16 mounted on the vehicle 14 receives the signal to cause the leakage radiation from the vehicle 2 and measures the position of the vehicle 14 based on the result. Therefore, it depends on whether or not the vehicle 14 is in the tunnel. The position of the vehicle 14 can be measured without any need, and thus a system in which the situation where position measurement is impossible is less likely to occur compared to GPS and the like can be obtained. In addition, since the position measurement based on the above-mentioned principle is based on the reception of the signal radiated and radiated from the leakage cable 12, it does not involve an integration calculation or the like. Therefore, the information obtained from the vehicle-mounted acceleration sensor, speed sensor, direction sensor, etc. It is possible to reduce the measurement error as compared with the method of integrating. Therefore, for example, when the position of the accident vehicle on the road is known to the vehicle 14 via VICS (Vehicle Information Communication System) or the like, a secondary disaster such as the vehicle 14 colliding with the accident vehicle is reliably prevented. Therefore, the safety of vehicle traffic on highways and the like can be further enhanced.

In addition, the calculation formula for position measurement is simple, easy to implement, and stable results are obtained. In addition, the transmitter 10 relating to the transmission using the transmitter identification pulse signal.
Is specified and the absolute position of the vehicle 14, for example, the position or mileage of the vehicle 14 with respect to a certain specific transmitter 10 is used as the base point is determined, so that not only the relative position but also the absolute position can be calculated. Also in this respect, a system with high usability can be obtained.

In the above description, the vehicle is mentioned as an example of the moving body that travels on the road, but the moving body to which the present invention is applied is not limited to the vehicle. Further, an example in which the transmitters 10 are arranged at a certain interval D has been shown.
This interval does not have to be constant, and the disposition interval of the transmitters 10 may be known in advance on the vehicle 14 side.

Further, in the above description, an example in which the transmitter identification period on the downstream side is followed by the transmitter identification period on the upstream side after the distance measurement period is shown, but the context of these three types of periods is shown. Can be changed. Also,
Although specific numerical examples are also shown, the present invention is not limited to such numerical examples. Regarding the detailed structure of the leakage cable 12, any of those shown in various prior art documents and known to those skilled in the art can be adopted. In addition, the measuring instrument according to the present invention can be used together with a conventional measuring instrument, for example, a GPS receiver or a receiver using dead reckoning.

[Brief description of drawings]

FIG. 1 is a layout diagram of a transmitter and a leakage cable showing a configuration of a road position measuring system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a measuring instrument according to this embodiment.

FIG. 3 is a timing chart showing the principle of position measurement and transmitter identification in this embodiment, in particular (a)
Is a timing chart showing the transmission timing of each transmitter, (b) is the transmission timing of the distance measurement pulse signal, and (c) is a timing chart showing the reception timing of the distance measurement pulse signal.

[Explanation of symbols]

10 transmitter, 12 leaky cable, 14 vehicle, 16
Measuring instrument, 20 receiver, 22 reception time difference counting section, 2
4 transmitter specifying unit, 26 relative position calculating unit, 28 absolute position calculating unit, 30 output unit, 32 transmitter position calculating unit,
34 traveling direction determination unit, D transmitter interval, L vehicle relative position (distance from transmitter), T measurement cycle, Tr pulse repetition cycle, Tt pulse transmission time difference, TL1, TL2
Reception delay, number of pulse signals for measuring P distance, number of pulse signals for identifying M transmitters, signal propagation speed on C leaky cable, number of N transmitters, t, t'pulse reception time difference.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G08G 1/0969 G01S 11/00 A

Claims (5)

[Claims] 1. A plurality of leaky cables are laid along the extension direction of the road and at least partially overlapping with any other leaky cable before measuring the position of a moving body traveling on the road. In addition, at least one transmitter is provided for each leaky cable, and at the time of measuring the above position, the distance from each transmitter to the corresponding leaky cable is synchronized with each other with a predetermined time difference. By transmitting the measurement pulse signal, the distance measurement pulse signal is radiated and radiated onto the road from the leaky cable, while the loading measuring instrument mounted on the moving body is radiated from the plurality of leaky cables. By wirelessly receiving the pulse signal for distance measurement, the receiving interval or distance difference of the pulse signal for distance measurement, the interval of the transmitter and the predetermined time difference, Road position measuring method characterized by measuring the relative position of the moving body with respect to the leakage cable to the transmitter along the extending direction of the serial road. 2. The road position measuring method according to claim 1, wherein the transmitter precedes or precedes the distance measuring pulse signal with a transmitter identifying pulse signal representing identification information unique to the transmitter. Then, by transmitting the signal to the corresponding leaky cable, the leaky radiation of the transmitter identification pulse signal is leaked from the leaky cable to the road, and the mobile unit leaks and radiates from the leaky cables. A road position measuring method comprising: wirelessly receiving a machine identification pulse signal, and measuring an absolute position of the moving body based on the identification information and the relative position extracted from the transmitter identification pulse signal. 3. A plurality of leak cables provided along the extension direction of the road so as to at least partially overlap with any other leak cables, and at least one leak cable is provided for each leak cable. And a transmitter that causes the distance measurement pulse signal to leak and radiate from the leaky cable to the road by transmitting the distance measurement pulse signal to the corresponding leaky cable in synchronization with each other with a predetermined time difference. Roadside equipment characterized by being provided. 4. A means for wirelessly receiving a distance measuring pulse signal leaking and radiating from the plurality of leaky cables included in the roadside equipment according to claim 3, and a distance measuring and leaking and radiating from different leaky cables. Means for measuring the relative position of the moving body with respect to the leaky cable or the transmitter along the extension direction of the road based on the reception interval or time difference of the pulse signal for use, the interval of the transmitter and the predetermined time difference, A load measuring device, which is mounted on a moving body traveling on the road. 5. The roadside equipment according to claim 3 and the load measuring device according to claim 4, wherein the transmitters are arranged at predetermined intervals along the extension direction of the road, The roadside position measuring method according to claim 1 or 2, wherein a plurality of leaky cables are laid so as to extend symmetrically in an upstream direction and a downstream direction of a road when viewed from a corresponding transmitter, and the roadside equipment and the load measuring device. A road position measuring system characterized by executing.