JPH05151497A - Car position detecting system in inter-lane communication system - Google Patents

Abstract

PURPOSE:To provide the car position detecting system of an inter-lane communication system in which the position locating of a mobile station is surely performed even on a crossroads and the junction of multiple roads. CONSTITUTION:A road station 50 sub-modulates transmission wave containing data using multiple code series whose auto-correlation value is large and cross- correlation value is small for transmitting it in each direction of a junction. A mobile station 12 demodulates the code series which is the sub-modulation wave of reception wave from the road station 50 and decides the direction of it, and then detects travelling direction against the road station 50, that is travelling direction at a junction, for locating car position. Thus, position locating for multiple-direction becomes possible, permitting effective position locating at a crossroads and a junction of multiple roads. Since a road station can be placed at a junction, more effective assignment of road stations is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road-to-vehicle communication system for communicating between a mobile station and a road station through which the mobile station passes, and more particularly to a road for evaluating the position of the mobile station with respect to the road station. The present invention relates to a vehicle position detection method in an inter-vehicle communication system.

[0002]

2. Description of the Related Art A road-vehicle communication system disclosed in Japanese Patent Application No. 63-38407 is known as a mobile communication system used for vehicles such as automobiles. In this road-vehicle communication system, roadside stations are arranged at predetermined intervals along the road, these roadside stations form intermittent communication areas, and vehicles passing through these communication areas are connected to the roadside stations. An on-vehicle device for communication is mounted, and when this vehicle passes through the communication area of each roadside station, it is configured to communicate with the roadside station using a common frequency. As one of usage forms of such a road-vehicle communication system, a navigation service such as a route guidance service for teaching an appropriate traveling route from a road station to a vehicle is considered. Such a navigation service collects traffic information such as the flow of vehicles detected at each roadside station and the regulation of each roadside at a higher-level station that controls the roadside station, and further, a detailed map of each point. It is a service that prepares data and transmits that information to the vehicle via each roadside station to accurately guide the vehicle to the destination, and is expected as an automatic navigation system in the future. In such navigation services, it is important to always know the vehicle position.

Conventionally, when detecting the position of a vehicle in a road-to-vehicle communication system, see, for example, "Telecommunication" issued by the Telecommunications Association of Japan, "Telecommunication" VOL.51, No.503, 11/1988 P.21 to P.27. The vehicle position detection method described is known. This vehicle position detection method radiates signal waves amplitude-modulated in opposite phases on the road up and down from a road station called a sign post installed along the road, and the degree of modulation of the sign post It is set to zero on the road in front. The wireless communication area of this sign post is 50 to 100 m. The vehicle side detects the amplitude modulation component of the signal wave radiated from the sign post when passing on the road in the communication area of this sign post, and detects that this amplitude modulation component becomes zero. The position of the vehicle with respect to the post was detected.

[0004]

However, in the above-described conventional vehicle position detecting method, since the signal wave emitted toward the road is simply amplitude-modulated in the opposite phase, for example, one There is a problem that it can only be used effectively on roads, that is, roads in the opposite direction of 180 degrees, and cannot be used at intersections. Therefore, the conventional system cannot detect the position when the vehicle passes the intersection, and after the vehicle passes the intersection, the position of the vehicle is not detected for the first time by the first sign post, and the road is often crossed with many intersections. In such cases, there was a problem that the accurate position information of the vehicle could not be obtained. Furthermore, on roads with many intersections or roads with many intersections, there is a problem that it becomes difficult to arrange roadside stations. For example, if the distance between adjacent intersections is short, it will be difficult to place a roadside station between them,
In the case of multiple crossings, there is a problem that it is difficult to effectively arrange the roadside stations, such as having to install the roadside stations on the roads of the respective directions.

The present invention solves the above-mentioned problems of the prior art and enables the position detection of a vehicle on a road in multiple directions, thereby enabling accurate position detection of a vehicle at an intersection, and therefore, accurate detection of the vehicle. It is an object of the present invention to provide a vehicle position detection method in a road-vehicle communication system which can obtain position information and can effectively arrange a roadside station.

[0006]

In order to solve the above-mentioned problems, a vehicle position detecting method in a road-to-vehicle communication system according to the present invention is directed to a mobile station and a roadside station installed near the road through which the mobile station passes. In a vehicle position detection method in a road-to-vehicle communication system that wirelessly communicates between a roadside station and a roadside station, the roadside station is installed in the vicinity of an intersection where a plurality of passages intersect, and a transmission wave to be transmitted to a mobile station is transmitted by a plurality of codes. The sub-modulation is performed by the sequence to generate a plurality of signal waves, and the signal waves are transmitted toward each direction of the intersection for each code sequence, and the mobile station transmits the signal waves transmitted from the roadside station. By receiving and demodulating the code sequence, the traveling direction of the own station with respect to the on-road station is detected and the position of the own station is evaluated.

In this case, the mobile station may add the identification code of its own station to the position evaluation information of its own station obtained for the on-road station and send it back to the on-road station. When the mobile station returns the position evaluation information and the identification code to the roadside station, the mobile station uses this information at random timing intervals based on the time when the mobile station evaluated its position with respect to the roadside station. Good to send.

Further, the code sequence for modulating the transmission wave at the roadside station is formed by a code sequence having a high autocorrelation value and a low cross-correlation value, and the mobile station sets the correlation of the code sequence in the received signal wave. The traveling direction of the vehicle may be detected by obtaining the value. Further, these code sequences are formed by a combination of a plurality of codes, and at least one of the up and down code sequences in each direction on the road may have a complementary relationship with each other. In addition, these code sequences are preferably complementary to each other in different directions of the intersection. Furthermore, these code sequences may be formed by pseudo noise sequences.
Moreover, these code sequences may be formed by a maximum long period sequence.

On the other hand, in a road-vehicle communication system for performing wireless communication between a mobile station and a road station installed near the road on which the mobile station passes, the road station has a high autocorrelation value and cross-correlation. Code sequence generation means for generating a plurality of code sequences with low values, sub-modulation means for modulating the transmission wave with each code sequence supplied from this code sequence generation means, and each supplied from this sub-modulation means And a signal transmitting means for transmitting the signal wave of (1) along each of a plurality of paths for each code sequence. In this case, the sub-modulation means may perform amplitude modulation.

Further, in a road-vehicle communication system for performing wireless communication between a mobile station and a roadside station installed near the road on which the mobile station passes, the mobile stations are respectively launched along the roadside. Demodulating means for demodulating the code sequence of
It is characterized by further comprising a determining means for determining in which direction the code sequence demodulated by the demodulating means is. In this case, the mobile station includes code sequence generation means for generating any one of the plurality of code sequences, and the determination means is the code sequence supplied from the code sequence generation means and the code sequence demodulated by the demodulation means. It is advisable to obtain the correlation value with and determine in which direction the code sequence is. In addition, the mobile station adds the identification code of its own station to the data processing means for generating the position evaluation information of its own station based on the judgment result from the judgment means, and the position evaluation information generated by this data processing means. It is preferable to provide a transmission means for transmitting to the roadside station. Further, the data processing means may supply the position evaluation information to the transmitting means at random timing based on the time when this information was generated.

[0011]

According to the vehicle position detecting method in the road-vehicle communication system according to the present invention, in the roadside station, the transmission wave to be transmitted to the mobile station is sub-modulated with a code sequence having a high autocorrelation value and a low cross-correlation value. Then, the signal wave of each code sequence is transmitted along each direction on the intersecting road, and the mobile station receives the signal wave, whereby the azimuth and position of the own vehicle with respect to the intersection can be detected. In this case, the mobile station generates the same code sequence as the modulated code sequence of the transmitted wave, takes the correlation value between this code sequence and the received code sequence, and determines the direction of the own station with respect to the intersection by determining the correlation value. You can then evaluate the position of your vehicle. Further, the mobile station adds the identification code of the own station to the position evaluation information including the detected own vehicle position, and returns this to the roadside station. Based on the information returned from the mobile station, the roadside station effectively provides a navigation service such as guiding a vehicle to a destination.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle position detecting system in a road-vehicle communication system according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 7 is a conceptual diagram of a road-vehicle communication system to which the vehicle position detecting method according to this embodiment is applied. The road-vehicle communication system in this figure has a predetermined interval along a straight road such as an ordinary road or a highway, for example,
A plurality of roadside stations 10 are arranged at intervals of several hundred meters to several kilometers. This interval is set to an appropriate value according to the vehicle speed allowed on the road, for example. In this embodiment, in particular, an on-road station 50 for an intersection (see FIG. 1) is arranged near each intersection separately from a straight road, and the distance between the on-road station 50 and this intersection is taken into consideration.
The distance between the roadside stations 10 is set. The roadside stations 10 and 50 are ground stations that function as base stations that wirelessly communicate with the subscribing vehicle 12 on the road. These roadside stations 10 and 50 have a communication area 20 much smaller than the distance between the roadside stations, for example, a communication area 2 of about 50 to 100 meters.
At 0, high speed communication is performed with the vehicle 12 traveling on the road for several seconds. The vehicle 12 is equipped with an on-vehicle device for communicating with the roadside stations 10 and 50.

In the road-vehicle communication system of this embodiment, a navigation service is provided to guide the vehicle 12 to an appropriate route according to the road congestion and weather conditions. This navigation service is a high-level station that controls the roadside stations 10, 50, to be precise, at the information center 26 connected to the high-level station via the communication network 22, the traffic flow measured by the roadside stations 10, 50 Obtain road information such as regulation information and weather information for each road, prepare detailed map data for each district, and store the road information in the vehicle 12 via the memory 42 of the roadside station 10,50. This is a service for transmitting and accurately guiding the vehicle 12 to the destination. Vehicles receiving this service 12
Is equipped with a display such as a CRT for displaying road information such as the above map data transmitted from the roadside stations 10,50. The vehicle 12 displays its own position on the map of this display to grasp the surrounding road condition.

Next, a road station for an intersection in this embodiment.
50 will be described in detail. As shown in FIG. 1, this on-road station 50 is equipped with an antenna that is installed in a corner toward the intersection and has directivity in each direction of the intersection.
Each emits a signal wave modulated with a different code sequence. Specifically, as shown in FIG. 2, the roadside station 50 in this embodiment includes a data processing unit 100 and a carrier wave oscillating unit 11.
0, the modulation unit 120, and a plurality of code sequence generation units (A to D) 130
~ 136, a plurality of amplitude modulation sections 140 to 146, antenna common sections 150 to 156, antenna elements 160 to 166,
A baseband conversion unit 170 and a data demodulation unit 180 are provided.

The data processing unit 100 is connected to a road-to-vehicle individual communication line network from the road-to-vehicle system center 26 shown in FIG.
The information is sequentially read from the memory 42 that stores the information supplied via 22 and these are used as modulation signals in the modulation unit 120.
It is a signal generation circuit for sending to. This modulated signal is 256k
It is transmitted as a relatively high-speed signal of bit / s to 1.5 Mbit / s, and includes control signals such as preamble, synchronization signal, and own station identification signal. This control signal indicates that the vehicle 12 is
Is an introduction signal transmitted when the vehicle enters any one of the communication areas. As the data supplied to the memory 42,
It includes road information such as the above-mentioned traffic flow and regulation information of each road, weather information, detailed map data of each district, and individual information for the vehicle 12. This data processing unit 180
Processes the data to extract the information sent by the radio waves. In the case of this embodiment, it is possible to recognize how fast the moving body 12 is approaching or moving away from a certain azimuth by taking out information in one block, which will be described later, sent out by the moving body 12. .. Further, the moving body 12 is identified by the identification code in one block sent out by the moving body 12.

The carrier wave oscillating unit 110 is composed of, for example, a high frequency oscillator of 800 MHz band, specifically a voltage controlled oscillator (VCO), and is directly modulated by the modulation signal supplied from the data processing unit 100. Is an oscillator that generates
The modulator 120 is the 800 MHz supplied from the carrier oscillator 110.
This is a main modulation circuit that modulates a band carrier signal with a modulation signal supplied from the data processing unit 100 and outputs it as a main modulation signal. More specifically, as shown in FIG. 4, the carrier wave is phase-modulated in every predetermined section, more precisely, BPSK (Bipolar Phase Shift Ke).
ying) It is composed of a phase modulator that modulates and generates a signal representing each bit.

The code sequence generators (A to D) 130 to 136 are signal generation circuits for generating a plurality of binary code sequences for notifying the mobile station 12 of the direction to the intersection. The code sequences generated from these code sequence generation units 130 to 136 are
Large auto-correlation value and small cross-correlation value, such as pseudo noise sequence (Pseudo Noise (PN) sequence, hereafter referred to as PN sequence) or maximum long period sequence (Maximal length (M) sequence)
Is used. In this embodiment, a code sequence in which two 2-bit PN codes are combined is used for the sake of clarity. For example, the code sequence generation unit (A) 130 generates a code sequence of "11" / "01", and the code sequence generation unit (B) 132 generates "00" / "01". "00" and "10" from the part (C) 134, and "11" and "1" from the code sequence generator (D) 136.
A code sequence signal of a set of 0 "is generated respectively. When the code sequence of the code sequence generating unit (A) 130 is PN1 · PN2, the code sequence of the code sequence generating unit (B) 132 is PN1 · PN. It becomes PN2, and the code sequence generator (A) 130 and code sequence generator (B) 132
The code sequence relationship between and is such that the code of PN2 is the same code and the code of PN1 is the complementary code sequence. These are used for ascending and descending in one direction at the intersection. The code sequence of the code sequence generation unit (C) 134 is bar PN1 and bar PN2, and both PN1 and PN2 have a complementary relationship with the code sequence of the code sequence generation unit (A) 130. The code sequence of the code sequence generation unit (D) 136 is PN1 · Bar PN2, and the code sequence of the code sequence generation unit (C) 134 has the same PN2 and complementary PN1. This is used as an up and down code sequence in the other direction at the intersection.

Amplitude modulation sections 140 to 146 code the main modulation signals demultiplexed from the modulation section 120 into code sequence generation sections 130 to 130, respectively.
This is a sub-modulation circuit that amplitude-modulates with a code sequence supplied from 136 and outputs as a composite modulation signal. For example, as shown in FIG. 5, the signal waveform output from the amplitude modulation section 140 is the “1101” code sequence supplied from the code sequence generation section (A) 130. Has been done. The bit "0" is modulated with amplitude A0, and the bit "1" is modulated with amplitude A1 which is larger than amplitude A0. Similarly, the signal waveform output from the amplitude modulator 142 is amplitude-modulated by "0001" as shown in FIG.
The amplitude modulators 144 and 146 also perform similar amplitude modulation.

Returning to FIG. 2, the antenna common parts 150-156.
Are multiplexers for switching the transmission / reception signals, respectively, and the antenna elements 160 to 16 use the composite modulation signals supplied from the amplitude modulators 140 to 146 as transmission waves.
It is a duplexer that supplies the received wave from the mobile station 12 that is output to the antenna 6 and received by the antenna elements 160 to 166 to the baseband converter 170 of the receiver. Antenna element
160 to 166 radiate the composite modulated signals supplied through the antenna sharing units 150 to 156 as transmission waves in each direction of the intersection, receive the radio waves transmitted from the mobile station 12, and receive the antenna sharing unit 150. Each is a signal transmitting / receiving element to be supplied to ~ 156. The antenna element 160 has directivity in the upward direction of the vertical road shown in FIG. 1, and the antenna element 162 has the directivity in the downward direction.
4 is in the left-right ascending direction in FIG.
Have directivity in the same downward direction and have communication areas W to Z of 25 to 50 m from the center of the intersection.

The baseband converter 170 is supplied with the received waves from the mobile station 12 received by the antenna elements 160 to 166 via the antenna common parts 150 to 156, and converts the received signals into intermediate frequencies. It is a conversion circuit. That is, the baseband conversion unit 170 is a signal conversion circuit that removes a carrier wave from a received wave, converts the carrier wave into a baseband signal, and converts the baseband signal into a signal that can be processed by a circuit in a subsequent stage. The signal converted into the baseband is output to the data demodulation unit 180. The data demodulation unit 180 is a demodulation circuit that demodulates the signal converted into the baseband into digital data that can be processed by the data processing unit 180.

Next, as shown in FIG. 3, the mobile station 12 according to the present embodiment includes an antenna element 200 and an antenna common part 2
10, the baseband converter 220, the detector 230, the code sequence generator 240, the correlation detector 250, and the position detector 26.
0, a data demodulator 270, a data processor 280, an identification code generator 290, a carrier wave oscillator 300, a data combiner 310, and a modulator 320.

The antenna element 200 is composed of, for example, an omnidirectional quasi-microwave antenna, and
A signal transmitting / receiving element for transmitting and receiving radio waves to and from the on-road stations 10 and 50 in the communication areas 20 of 10 and the communication areas W to Z of the on-road station 50. The antenna sharing unit 210 is a multiplexer that switches the transmission / reception signals, outputs the radio wave received by the antenna element 200 to the baseband conversion unit 220 as a reception wave, and transmits the transmission signal from the modulation unit 320 of the transmission unit to the antenna element. It is a duplexer that supplies to 200 as a transmission wave. The baseband converter 220 is a signal converter that converts a received wave supplied via the antenna duplexer 210 into a baseband signal that can be demodulated.

The detection section 230 is a demodulation circuit for discretely detecting the baseband signal supplied from the baseband conversion section 220 to demodulate the amplitude component of the received wave. Particularly, in the case of the received wave from the roadside station 50, the above-mentioned code sequence is demodulated. The code sequence generation unit 240, for example,
This is a signal generation circuit that generates the same code sequences PN1 and PN2 = "0011" as the code sequence generation circuit (A) 130 of the roadside station 50 described above. The correlation detection unit 250 takes a correlation value between the signal detected by the detection unit 230 and the code sequences PN1 and PN2 supplied from the code sequence generation unit 240, and outputs the correlation result to the azimuth detection unit 260 as azimuth information. This is a determination circuit for outputting. For example, in the case of this embodiment, since the code sequence included in the received wave is a combination of two PN codes, the correlation detection unit 250 takes a correlation value for each PN code, and, for example, in the W region of FIG. Correlation value "11", correlation value "01" in X area, "0" in Y area
Correlation value "1" indicates a positive correlation, and correlation value "0" indicates a negative correlation. The data processing unit uses the judgment result supplied from the unit 250 as the traveling direction information of the own vehicle.
The position determination circuit outputs the result to the data processing unit 280, and outputs to the data processing unit 280 the position detection result in the no-radio wave region near the center of the change point, that is, the intersection.

The data demodulation section 270 is a demodulation circuit that demodulates a phase modulated wave from a baseband signal to restore received data. The data processing unit 280 processes the data in order to extract the information necessary for the vehicle from the demodulated signal, and the information from the azimuth detecting unit 260 to generate it as data that can be displayed on an output device such as a display. Is a processing circuit. In addition, the data processing unit 280 in this embodiment evaluates the position of the own vehicle from the demodulated data from the data demodulation unit 270 and the direction information from the direction detection unit 260, and the direction information, position information, speed information, etc. The data synthesizing unit 30 of the transmitting unit includes the position evaluation information composed of
This is a data generation circuit that supplies 0. The data processing unit 280 has a timing circuit having a random number generation function and a counting function, and after receiving the information from the azimuth detection unit 260 and generating position evaluation information, a random numerical value from the random number generation circuit. According to the above, the counting circuit counts the time, and the timing interval for sending the position evaluation information to the data synthesizing circuit 300 is determined.

In the transmitting section, the identification code generating section 290
It is a circuit that generates an identification code assigned to each vehicle or each in-vehicle device. This identification code generator
290 is configured by, for example, a ROM (Read only memory) or the like, an identification code is stored in advance, and the identification code is read in response to the transmission of the position evaluation information from the data processing unit 280. The carrier wave oscillator 300 is similar to the carrier wave oscillator 300 of the roadside station 50, for example, 800 MHz.
It is composed of a high frequency oscillator in the band, specifically a voltage controlled oscillator (VCO). The data synthesizing unit 310 synthesizes the identification code from the identification code generating unit 290 and the position evaluation information from the data processing unit 280 as one block, and the modulating unit 32
This is a synthesizing circuit that sends a modulated signal to 0. Modulator 120
Is a modulation circuit that modulates the 800 MHz band carrier signal supplied from the carrier wave oscillating unit 110 with the modulation signal supplied from the data synthesizing unit 310 and outputs the modulated signal to the antenna common unit as a transmission signal. Advantageously, a multi-level modulation method such as BPSK modulation generally used for data transmission is used.

The position detecting method of the road-vehicle communication system of this embodiment having such a configuration will be described together with the operation of each of the above parts. In this embodiment, a case where the vehicle 12 passes through the intersection shown in FIG. 1 will be described in particular.

When the vehicle 12 enters one of the communication areas of the roadside station 50, the roadside station 50 transmits to the vehicle 12 an introduction signal including a preamble, a synchronization signal, an identification code of its own station, and the like. In the vehicle-mounted device of the vehicle 12, by receiving the preamble and the synchronization signal of this introduction signal, it is possible to accurately take the reception synchronization of the communication wave to be transmitted later, and by receiving the identification code, The road station 50 can be identified. In response to the reception of these signals, the vehicle 12 transmits its own identification signal to the roadside station 10. The transmission of the introduction signal from the roadside station 50 and the transmission of the identification signal from the vehicle 12 are performed almost instantaneously, and the vehicle 12 enters the communication area of the roadside station 50 within 2 to 3 meters thereof. Transmission and reception is performed.

Following this, bidirectional communication is performed between the vehicle 12 and the roadside station 50. At this time, the roadside station 50
Sends communication data such as navigation services. While the signal is being transmitted for several seconds, the vehicle 12
Passes through the center of the intersection and detects its position. In this case, in the roadside station 50, the data processing unit 100 sequentially outputs the data read from the memory 42 as a modulation signal to the modulation unit 120, and the modulation unit 120 sequentially outputs the carrier signal from the carrier transmission unit 120 as a modulation signal. Phase-modulate. As a result, the phase modulation wave shown in FIG. 4 is transmitted from the modulator 120. The phase modulated waves are amplitude-modulated by the code sequences supplied from the code sequence generators 130 to 136 in the amplitude modulators 140 to 146, respectively, and are used as signal waves as shown in FIGS. It is supplied to the antenna elements 160 to 166 via the parts 150 to 156. As a result, communication waves are radiated from the respective antenna elements 160 to 166 to the respective communication areas W to Z at the intersection shown in FIG.

Assuming that the mobile station 12 is entering the intersection from the up and down area Y in the left-right direction shown in FIG.
12 is the code sequence "11" ・ "before reaching the center of the intersection.
The communication wave sub-modulated at 10 "is received. The received wave is supplied from the antenna element 200 of the mobile station 12 to the baseband conversion section 220 via the antenna sharing section 210 and becomes a baseband signal. The baseband signal is detected by the detection unit 230, and the signal of the code sequence "11" / "00" represented by its amplitude component is detected, and this code sequence signal is supplied to the correlation detection unit 250. The correlation detection unit 250 takes the correlation value between the code sequence "11" / "10" and the code sequence "00" / "01" supplied from the code sequence generation unit 240 of the local station. The determination signal "00" indicating that the vehicle has entered the intersection from the left and right upward lines is supplied from the section 250 to the intersection via the azimuth detecting section 260 to the data processing section 280. During this time, the baseband signal is transmitted to the data demodulation section. The data demodulated and restored by the 270 is supplied to the data processing unit 280. That. The data is processed by the data processing unit 280,
For example, a map data update screen is displayed on the display, and a map near the intersection is displayed. In addition, the display of traffic flow and traffic restrictions near the intersection is output from the output device as characters and voice. At this time, the data processing unit 280
Generates, as one block, position evaluation information that evaluates the position of the own station from the azimuth information obtained from the azimuth detection unit 260, the information included in the data-processed information, and the like. When this block is generated, a random timing time is counted by an internal timing circuit, and when the count value is reached, position evaluation information is sent to the data synthesizing unit 310. This position evaluation information is stored in the data synthesis unit 310 in the identification code generation unit 29.
The identification code from 0 is added and supplied to the modulation unit 320, and is supplied to the antenna element 200 via the antenna sharing unit 210 as a transmission wave in which the carrier wave is phase-modulated by the modulation unit 320, and is returned to the roadside station 50. To be done.

During this time, when the mobile station 12 reaches the vicinity of the center of the intersection, the output from the correlation detecting section 250 is stopped, whereby the position detecting section 260 detects that the center section of the intersection has been passed, and The detection result is supplied to the data processing unit 280. Thereby, the vehicle position displayed on the display is corrected. Next, if the mobile station 12 makes a right turn, for example, in the up line area W in the vertical direction in FIG. 1, the code sequence which is the sub-modulation signal of the received wave from the road station 50 is "00".
・ It becomes "01". As a result, the correlation detecting unit 250 of the mobile station 12 outputs the correlation value “11” between the detected code sequence and the code sequence from the code sequence generating unit 240 of the own station. As a result,
The traveling direction of the vehicle at the intersection is determined, and the data processing unit 280 displays the data regarding the traveling direction of the vehicle and the information such as the moving speed of the vehicle on the display to determine the position of the vehicle. In this case as well, similar to the above, the position evaluation information is transmitted to the roadside station 50 via the antenna 200 as a transmission wave modulated by the modulator 320 together with the identification code.
Sent to. By the feedback of the position evaluation information from the mobile station 12 to the roadside station 50, it is transmitted to the system center 26 as traffic flow information. Similarly, if the vehicle is in the Z area or X
Also when going to the area, the code sequence which is the sub-modulation wave in the area is detected and processed as data as azimuth information, and this data is notified to the driver by the display on the mobile station 12 and the roadside station 50. Then, it is transmitted as traffic flow information to the system center 26 by feedback from the mobile station 12.

In this embodiment, a code sequence in which two PN codes are combined is used as the code sequence signal, but in the present invention, if the code sequence has a large autocorrelation value and a small cross-correlation value. Either code sequence may be used. In this case, correlation detection section 250 exhibits a positive correlation for the same series portion and a negative correlation for the complementary series portion. Also, in the case of different series, it becomes almost zero. In the present invention, the data processing unit 280 can identify the moving direction of the vehicle by setting the output value of the correlation detection unit based on these.

Further, in the above embodiment, it is possible to evaluate the position of the vehicle at an intersection such as a crossroads by using two kinds of signals PN1 and PN2 in the code sequence, but in the case of a six-way road, The position of the vehicle may be evaluated using three types of signals for the code sequence. Similarly, in the case of multiple intersections, the position of the vehicle may be evaluated by a combination of the number of signals according to the number of intersections.

Further, in the above embodiment, the roadside station 50
The data is BPSK modulated by the mobile station 12, but the present invention is not limited to this, and other modulation methods such as frequency modulation and amplitude modulation may be used.

[0035]

As described above, according to the vehicle position detecting method in the road-vehicle communication system according to the present invention, since the transmission wave is amplitude-modulated by a plurality of code sequences in the roadside station, it is transmitted at many intersections. It is possible to evaluate the position even on the road in the direction.

Therefore, the mobile station has an effect of being able to accurately grasp the position and the traveling direction of the own station at the intersection by identifying the code sequence of the received wave. Further, since the roadside station can be arranged at the intersection, in the vicinity of the intersection, the distance between the other roadside stations can be determined on the basis of the roadside station to effectively arrange the roadside station.

Further, since the position evaluation information for the on-road station obtained by the mobile station is returned to the on-road station, the on-road station sends this information to the upper station, and the upper station accurately determines the traffic flow at those intersections. It is possible to obtain an excellent effect that the navigation service such as the route guidance service can be effectively performed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a vehicle position detecting method in a road-vehicle communication system according to the present invention.

FIG. 2 is a block diagram showing a circuit example of a roadside station applied to the embodiment.

FIG. 3 is a block diagram showing a circuit example of a mobile station applied to the embodiment.

FIG. 4 is a diagram showing a waveform example of a main modulation signal in the example.

FIG. 5 is a diagram showing a waveform example of a sub-modulation signal in the example.

FIG. 6 is a diagram showing a waveform example of the sub-modulation signal.

FIG. 7 is a conceptual diagram showing a road-vehicle communication system to which this embodiment is applied.

[Explanation of symbols]

 12 Mobile station 50 Roadside station 100 Data processing unit 110 Carrier oscillation unit 120 Modulation unit 130 to 136 Code sequence generation unit 140 to 146 Amplitude modulation unit 150 to 156 Antenna sharing unit 160 to 166 Antenna element 170 Baseband conversion unit 180 Data demodulation unit 200 Antenna element 210 Common antenna section 220 Baseband conversion section 230 Detection section 240 Code sequence generation section 250 Correlation detection section 260 Position detection section 270 Data demodulation section 280 Data processing section 290 Identification code generation section 300 Carrier wave generation section 310 Data synthesis section 320 Modulator

Claims (14)

[Claims] 1. A vehicle position detection method in a road-vehicle communication system for wirelessly communicating between a mobile station and a road station installed near a road on which the mobile station passes, wherein the road station comprises: Installed in the vicinity of an intersection where a plurality of passages intersect, a transmission wave to be transmitted to the mobile station is sub-modulated by a plurality of code sequences to generate a plurality of signal waves, and the signal waves are generated for each code sequence. Transmitting toward each direction of the intersection, the mobile station receives the signal wave transmitted from the roadside station, and demodulates the code sequence to detect the traveling direction of the own station with respect to the roadside station. A vehicle position detection method in a road-vehicle communication system, characterized in that the position of the own station near the intersection is evaluated. 2. The vehicle position detection method in the road-to-vehicle communication system according to claim 1, wherein the mobile station adds an identification code of the own station to position evaluation information of the own station obtained for the on-road station. A vehicle position detecting method in a road-to-vehicle communication system, wherein the vehicle position is detected by the roadside station. 3. The vehicle position detecting method in the road-vehicle communication system according to claim 2, wherein when the mobile station returns the position evaluation information and the identification code to the on-road station, the mobile station sends the information to the mobile station. A vehicle position detecting method in a road-vehicle communication system, characterized in that transmission is performed at random timing intervals based on the time when the position of the own station is evaluated with respect to the roadside station. 4. The vehicle position detecting method in the road-vehicle communication system according to claim 1, wherein the code sequences for modulating the transmission waves at the road stations have high autocorrelation values,
And formed by a code sequence having a low cross-correlation value, the mobile station, by obtaining the correlation value of the code sequence in the received signal wave, to identify the code sequence to detect the traveling direction of the own vehicle. A vehicle position detection method for a road-to-vehicle communication system. 5. The vehicle position detection method in the road-vehicle communication system according to claim 4, wherein the code sequence is formed of a combination of a plurality of codes, and at least an up-and-down code sequence in each direction on the road. A vehicle position detection method in a road-vehicle communication system, wherein any one of the codes has a complementary relationship. 6. The vehicle position detecting method for a road-vehicle communication system according to claim 4, wherein the code sequences are complementary to each other in different directions of the intersection. Position detection method. 7. The vehicle position detecting method in the road-vehicle communication system according to claim 4, wherein the code sequence is formed by a pseudo noise sequence. 8. The vehicle position detecting method in the road-vehicle communication system according to claim 4, wherein the code sequence is formed by a maximum long cycle sequence. 9. A road-vehicle communication system for wirelessly communicating between a mobile station and a road station installed near the road on which the mobile station passes, wherein the road station has a high autocorrelation value. , And a code sequence generation means for generating a plurality of code sequences having a low cross-correlation value, a sub-modulation means for sub-modulating the transmission wave with each code sequence supplied from the code sequence generation means, and the sub-modulation means. And a signal transmitting means for transmitting each of the signal waves supplied from each of the respective code sequences along a plurality of intersecting paths, respectively. 10. The road-vehicle communication system according to claim 9, wherein the sub-modulation means performs amplitude modulation. 11. A road-to-vehicle communication system for performing wireless communication between a mobile station and a road station installed near the road on which the mobile station passes, wherein the mobile station is transmitted along the road. A road-vehicle communication system comprising: a demodulation unit that demodulates each code sequence, and a determination unit that determines in which direction the code sequence demodulated by the demodulation unit is. 12. The road-vehicle communication system according to claim 11, wherein the mobile station includes a code sequence generation unit that generates any one of a plurality of code sequences, and the determination unit includes the code sequence generation unit. A road-to-vehicle communication system, characterized in that a correlation value between a code sequence supplied from a code sequence generating means and a code sequence demodulated by the demodulating means is obtained to determine which direction the code sequence is. 13. The road-vehicle communication system according to claim 11, wherein the mobile station generates data for evaluating the position of the mobile station based on the determination result from the determination means, and the data processing means. And a transmission means for adding the identification code of the own station to the position evaluation information generated in 1. and transmitting the same to the on-road station. 14. The road-vehicle communication system according to claim 13, wherein the data processing unit generates the position evaluation information, and then, at a random timing, based on the time when the information is generated, the data processing unit stores the information. A road-vehicle communication system characterized by supplying to said transmitting means.