JP2009198374A - Position information generating ystem, position information generating evice, computer program, and position information generation method - Google Patents

Abstract

A position information generating system capable of accurately specifying the position of a moving body such as a vehicle, a position information generating apparatus constituting the position information generating system, a computer program and a position for realizing the position information generating apparatus An information generation method is provided.
An in-vehicle device 100 transmits a first signal to a first communication unit and a second communication unit of a roadside device, and receives a second signal transmitted by the first communication unit and the second communication unit of the roadside device. By receiving, the distance L1 from the 1st communication part of the vehicle equipment 100 is calculated, and the distance L2 from the 2nd communication part of the vehicle equipment 100 is calculated. The in-vehicle device 100 generates position information by specifying an intersection of a circle or a sphere centered on the positions of the first communication unit and the second communication unit as its own position.
[Selection] Figure 2

Description

  The present invention relates to a position information generation system that generates information related to the position of a moving body, a position information generation apparatus that constitutes the position information generation system, a computer program for realizing the position information generation apparatus, and a position information generation method.

2. Description of the Related Art Conventionally, a system for detecting the position of a radio wave source called an unknown station such as a moving body that radiates radio waves has been developed. For example, radio waves emitted from a radio wave source are received by a plurality of sensor stations, and each sensor station takes out a radio wave for a fixed time using a reference time output from a GPS receiver as a trigger, and performs a Fourier transform to obtain a complex frequency component. The extracted complex frequency component is transmitted to the center station. A position detection system has been proposed in which the center station calculates the complex conjugate product between the complex frequency components transmitted from each sensor station, calculates the arrival time difference between the sensor stations, and detects the position of the radio wave source ( Patent Document 1).
Japanese Patent No. 3739078

  However, in the system of Patent Document 1, when calculating the arrival time of the signal from the radio wave source to the sensor station, the radio wave source time and the sensor station time are synchronized, that is, the radio wave so that the time is the same. It is necessary to adjust the clock of the source or sensor station. However, as a practical problem, it is difficult to make the time of both watches the same, and a slight time difference occurs. Further, there is no function for monitoring whether or not the time of each sensor station is shifted, and a specific method for synchronizing the time between the sensor stations is not disclosed. For this reason, a system capable of accurately detecting the position of the moving body has been desired.

  The present invention has been made in view of such circumstances, and a position information generation system capable of accurately generating information related to the position of a moving body such as a vehicle, and a position information generation apparatus constituting the position information generation system An object of the present invention is to provide a computer program and a position information generation method for realizing the position information generation apparatus.

  A position information generation system according to a first aspect of the present invention includes at least two communication devices including a communication device mounted on a mobile body, and generates information related to the position of the mobile body by transmitting and receiving a predetermined signal between the communication devices. In the position information generation system, one communication device includes a transmission unit that transmits a first signal to another communication device, and a reception unit that receives a second signal transmitted by the other communication device. The other communication apparatus includes: a receiving unit that receives the first signal; and a first reception time point at which the first signal is received by the receiving unit to a second transmission time point of the second signal. And transmitting means for transmitting the second signal including time information relating to the time of the second time, wherein the one communication device transmits the first signal at a second reception time point when the second signal is received. Based on the first transmission time and the time information Characterized by further comprising a generating means for generating distance information from the communication device other than mounting the moving body of the mobile communication device.

  In a positional information generating system according to a second aspect based on the first aspect, the one communication device includes a distance acquiring unit that acquires a moving distance of the moving body, and the generating unit starts from the first transmission time point. The distance information of the moving body is generated based on the distance that the moving body has moved between the two reception times.

  In a second aspect of the positional information generating system according to the third aspect of the present invention, the one communication device includes azimuth acquiring means for acquiring a moving azimuth of the moving body, and the generating means is configured to start from the first transmission time point. The distance information of the moving body is generated based on the direction in which the moving body has moved between the two reception times.

  According to a fourth aspect of the present invention, there is provided the positional information generating system according to any one of the first to third aspects, wherein each communication device includes a time measuring unit that operates with a reference clock for time measurement. The time measurement error of the time measuring means is smaller than the time measurement error of the time measuring means of the one communication device, and the other communication device is a measuring means for measuring the time error of the time measuring means of the one communication device, and the measurement means. Transmitting means for transmitting the measurement result measured in step 1 to the one communication apparatus, wherein the one communication apparatus is configured to receive the first measurement result based on the reception means that receives the measurement result. Correction means for correcting the time from the time point to the second reception time point.

  In a fourth aspect of the positional information generating system according to the fifth aspect of the present invention, the one communication device transmits a reference clock correction signal including a known frequency component between the communication devices to the other communication device. The other communication device includes an extraction unit that extracts a frequency component of the reference clock correction signal, and the measurement unit is configured to perform the one communication based on the frequency component extracted by the extraction unit. The time measuring error of the time measuring means of the apparatus is configured to be measured.

  In a fourth aspect of the positional information generating system according to the sixth aspect of the present invention, the one communication device is configured to transmit a reference clock correction signal having a known time length between the communication devices to the other communication device. The other communication device includes an extracting unit that extracts a time length of the signal for correcting the reference clock, and the measuring unit is configured to extract the one communication device based on the time length extracted by the extracting unit. The time measuring means is configured to measure a time error.

  In a fourth aspect of the positional information generating system according to the seventh aspect of the present invention, the one communication device transmits the first signal including a known frequency component or the first signal having a known time length. The other communication device includes an extracting unit that extracts a frequency component or a time length of the first signal, and the measuring unit is based on the frequency component or the time length extracted by the extracting unit. The time-measurement error of the time-measurement means of the one communication device is configured to be measured.

  The positional information generating system according to an eighth aspect of the present invention is the system according to any one of the fourth to seventh aspects, wherein the other communication device is configured to acquire an acquisition unit that acquires a moving speed and a moving direction of a moving body; Calculating means for calculating the Doppler shift amount of the signal based on the moving speed and the moving direction acquired in Step 1, and compensating means for compensating for the time error measured by the measuring means so as to cancel out the Doppler shift amount calculated by the calculating means. It is characterized by providing.

  According to a ninth aspect of the present invention, in the positional information generation system according to any one of the fourth to seventh aspects, the one communication device includes a storage unit that stores a moving speed and a moving direction of the moving body, and a stored movement. A calculating means for calculating a Doppler shift amount of a signal based on a speed and a moving direction, and a timing error of the timing means based on a measurement result received by the receiving means to cancel out the Doppler shift amount calculated by the calculating means. Compensating means for compensating for the above is provided.

  The positional information generating system according to a tenth aspect of the present invention is characterized in that, in any one of the first to ninth aspects, the first signal and the second signal are known signals between communication devices. To do.

  According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, the first signal and the second signal include an identifier unique to the transmission source of the first signal. It is characterized by that.

  A positional information generation system according to a twelfth aspect of the present invention includes the communication apparatus according to any one of the first to eleventh aspects, further comprising at least two communication apparatuses in addition to the communication apparatus mounted on the mobile body, Storage means for storing the position information of each communication device other than the communication device mounted on the mobile body, the generation means is configured to generate distance information from each communication device of the mobile body, It is characterized by comprising position information generating means for generating position information of the moving body based on the distance information generated by the generating means and the stored position information.

  According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the communication device according to the twelfth aspect includes storage means for storing road shape information of a moving area of the moving body, and the position information generation means stores the stored road. It is configured to generate position information of a moving body using shape information.

  According to a fourteenth aspect of the present invention, in the twelfth or thirteenth aspect of the present invention, the one communication device includes storage means for storing height information of a position of the communication device mounted on the mobile body, The information generating means is configured to generate position information of the moving body using the stored height information.

  A position information generation apparatus according to a fifteenth aspect of the present invention is a position information generation apparatus that generates information about its own position by transmitting and receiving a predetermined signal to and from a communication apparatus, and transmits the first signal to the communication apparatus. And second information including time information relating to a time from a first reception time point when the communication device receives the first signal to a second transmission time point of the second signal transmitted by the communication device. Based on the reception means for receiving the signal from the communication device, the second reception time point at which the second signal is received by the reception means, the first transmission time point at which the first signal is transmitted, and time information. And generating means for generating distance information from the communication device of itself.

  A position information generation device according to a sixteenth aspect of the present invention is a position information generation device that generates information related to the position of the mobile body by transmitting and receiving a predetermined signal to and from a communication device mounted on the mobile body. A transmission means for transmitting a signal to the communication device; and a time from a first reception time at which the communication device receives the first signal to a second transmission time of the second signal transmitted by the communication device. Receiving means for receiving the second signal including time information from the communication device; a second reception time point when the second signal is received by the receiving means; and a first transmission for transmitting the first signal And generating means for generating distance information to the moving object based on the time point and time information.

  A computer program according to a seventeenth aspect of the present invention is a computer program that causes a computer to generate information related to its own position based on a first signal transmitted to a communication device and a second signal received from the communication device. Calculating means for calculating a time from a first transmission time point at which the first signal is transmitted to a second reception time point at which the second signal is received; and calculating the time and the first signal to the communication Generation for generating distance information from the communication device of itself based on time information relating to a time from a first reception time point received by the device to a second transmission time point when the communication device transmits the second signal. It is made to function as a means.

  A computer program according to an eighteenth aspect of the invention generates information relating to the position of the mobile body based on a first signal transmitted to a communication device mounted on the mobile body and a second signal received from the communication apparatus. A computer program for causing a computer to calculate a time from a first transmission time point at which a first signal is transmitted to a second reception time point at which a second signal is received; Distance information to the moving body based on time information regarding a time from a first reception time point when the communication device receives the first signal to a second transmission time point when the communication device transmits the second signal. It is made to function as a production | generation means to produce | generate.

  A position information generating method according to a nineteenth aspect of the present invention is a position information generating method for generating information related to the position of the mobile body by transmitting and receiving a predetermined signal between at least two communication apparatuses including a communication apparatus mounted on the mobile body. The first communication device transmits a first signal to another communication device, and the other communication device receives the first signal and receives the first signal at a first reception time point. The second signal including time information related to the time from the first signal to the second transmission time point of the second signal transmitted by itself is transmitted to the one communication device, and the one communication device transmits the second signal. And a second transmission time point when the second signal is received, a first transmission time point when the first signal is transmitted, and the time information. It is characterized by generating distance information from other communication devices. .

  In the first invention, the fifteenth invention, the sixteenth invention, the seventeenth invention, the eighteenth invention, and the nineteenth invention, the position information generation system includes at least two communication devices including a communication device mounted on a mobile body. . One communication device transmits the first signal to another communication device. The other communication device receives the first signal. When the other communication device transmits the second signal to the one communication device, the other communication device receives the second signal that is the second signal transmission time from the first reception time tb1 when the first signal is received. The time information related to the time until the transmission time tb2 is included in the second signal and transmitted. Here, the time information may be the first reception time point tb1 and the second transmission time point tb2 itself, or may be an elapsed time from the first reception time point tb1 to the second transmission time point tb2. The one communication apparatus receives the second signal, and sets the received time as the second reception time ta2. The one communication device is a communication device other than the communication device on which the moving body is mounted based on the second reception time point ta2, the first transmission time point ta1 at which the first signal is transmitted, and the time information (tb1, tb2). The distance information from the communication device is generated.

  When one communication device is mounted on a mobile body, when the distance traveled between the time when the first communication device transmits the first signal and the time when the second signal is received can be ignored, The distance information (for example, the distance L) from the other communication device of the moving body can be obtained by adding one-half of the signal propagation time T to the signal propagation speed. Here, the signal propagation time T is T = ta2-ta1- (tb2-tb1). When another communication device is mounted on the mobile body, the distance traveled by the other communication device is ignored after the first communication device transmits the first signal and before receiving the second signal. When it is possible, the distance information to the moving body can be similarly obtained by adding half the signal propagation time T to the signal propagation speed. Thereby, even if the time between communication apparatuses is not synchronized, the information (distance information) regarding the position of the moving body can be obtained with high accuracy.

  In the second aspect of the invention, the one communication device can determine the distance of the moving object based on the distance (for example, X) that the moving object has moved from the first transmission time ta1 to the second reception time ta2. Generate information. For example, when one communication device is mounted on a mobile body, when the mobile body is moving in a direction substantially equal to the direction of the other communication device, distance information (for example, the mobile body from other communication devices) , Distance L) can be set to one half of the value obtained by subtracting the moving distance X of the moving body from the value obtained by adding the signal propagation time T to the signal propagation speed. The distance L is the distance at the second reception time. Thereby, even if the moving body is moving, information (distance information) regarding the position of the moving body can be obtained with high accuracy. The same applies when other communication devices are mounted on the mobile body.

  In the third aspect of the invention, the one communication device adds the moving direction (for example, the moving direction and the moving direction) in addition to the distance moved by the moving body from the first transmission time ta1 to the second reception time ta2. The distance information of the moving body is generated based on the angle θ) with the direction between the communication devices. For example, when one communication device is mounted on a moving body, the angle between the moving direction and the direction between the communication devices at the first transmission time ta1 of the one communication device is θ1, and the second of the one communication device is the second. The angle between the direction of movement at the reception time ta2 and the direction between the communication devices is θ2, the distance that the moving body has moved between the first transmission time ta1 and the second reception time ta2 is X, and the signal propagation speed is signaled. If the propagation distance of the signal multiplied by the propagation time T is L and the traveling direction of the moving body is substantially on a straight line, the distance Y from the other communication device of the moving body at the second reception time is Y = (L · cos θ1−X) / (cos θ1 + cos θ2). Here, θ1 and θ2 indicate that the direction from one communication device toward another communication device is 0 degree. Thereby, when the moving body is moving, information (distance information) regarding the position of the moving body can be obtained with high accuracy regardless of the moving direction of the moving body. The same applies when other communication devices are mounted on the mobile body.

In the fourth invention, each communication device measures time based on the reference clock. When one communication device is mounted on a moving body, the time error of the other communication device is smaller than the time error of the one communication device. For example, when one communication device is an in-vehicle device, the reference clock has a relatively large error, and has an accuracy of about 10 ⁻⁵ to 10 ⁻⁶ as an example. On the other hand, when the other communication device is a roadside device, the clock from the GPS satellite can be extracted. As an example, the accuracy is higher than the clock of the vehicle-mounted device of about 10 ⁻⁸ to 10 ^−9. Have

  The other communication device measures a time error of the one communication device and transmits the measured measurement result to the one communication device. In this case, for example, one communication device transmits a signal including a known frequency component or a signal having a known time length to another communication device, and the other communication device transmits a frequency component or signal from the received signal. By extracting the time length, it is possible to measure a time measurement error corresponding to a difference from a known frequency or time length in advance. The one communication device receives the measurement result, and corrects the time from the first transmission time ta1 to the second reception time ta2 based on the received measurement result. As a result, the timing error may differ between the communication devices, and the degree of time advance or delay can be matched between the communication devices in real time. You can ask well. In this case, it is not necessary for the communication devices to have the same time. The same applies when another communication device is mounted on the mobile body.

  In the fifth invention, one communication device transmits a reference clock correction signal including a known frequency component between the communication devices to another communication device, and the other communication device receives the received reference clock correction. The frequency component of the signal is extracted. The reference clock correction signal is not limited to a signal used only for reference clock correction, and may be a signal used for reference clock correction and other purposes. Another communication apparatus measures a time error of one communication apparatus based on a difference between the extracted frequency component and a previously known frequency component. For example, when the known frequency is 1 GHz and the frequency component extracted by another communication device is 1.000001 GHz, the clock (clock) of one communication device is 1 ppm faster than the clock (clock) of the other communication device. I understand that. Thereby, the advance degree or the delay degree of the clock (clock) between the communication apparatuses can be accurately measured.

  In the sixth invention, one communication device transmits a reference clock correction signal having a known time length between the communication devices to another communication device, and the other communication device receives the received reference clock correction signal. The time length of the signal is extracted. The other communication device measures the time error of one communication device based on the difference between the extracted time length and the previously known time length. For example, when the known time length of a signal is 10 milliseconds and the time length of a signal extracted by another communication apparatus is 10 nanoseconds longer than 10 milliseconds, the clock (clock) of one communication apparatus is It can be seen that it is 1 ppm later than the clock (clock) of the communication device. Thereby, the advance degree or the delay degree of the clock (clock) between the communication apparatuses can be accurately measured.

  In the seventh invention, one communication device transmits a first signal including a known frequency component or a first signal having a known time length, and the other communication device receives the received first signal. The frequency component or time length of is extracted. Another communication apparatus measures a time error of one communication apparatus based on a difference between the extracted frequency component or time length and a previously known frequency component or time length. Thereby, the advance degree or the delay degree of the clock (clock) between the communication apparatuses can be accurately measured.

  In the eighth invention, when one communication device is mounted on the moving body, the other communication device acquires the moving speed and moving direction of the moving body, and based on the acquired moving speed and moving direction. The Doppler shift amount (frequency) of the signal is calculated. In this case, the moving speed and moving direction can be transmitted from one communication apparatus to another communication apparatus. When one communication apparatus transmits a signal having a frequency f0, the frequency f of a signal received by another communication apparatus can be expressed by f≈f0 (c + V · cos θ) / c. Thereby, the Doppler shift amount is calculated. Here, f0 is a known frequency between communication devices, V is a moving speed, θ is an angle between the moving direction and the direction between communication devices, and c is the speed of light. Other communication apparatuses compensate for the time measurement error measured to cancel the calculated Doppler shift amount. Thereby, even when the moving speed of the moving body is high, the time measurement error can be obtained with high accuracy.

  In the ninth invention, the one communication device is mounted on the moving body. One communication apparatus acquires the moving speed and moving direction of the moving body, and stores the acquired moving speed and moving direction. One communication apparatus receives a time measurement error (for example, a clock deviation for time measurement, a difference from a previously known frequency or time length, or a frequency or time length itself) from another communication apparatus. For example, when a frequency is used as a time measurement error, one communication apparatus calculates a Doppler shift amount (frequency) of a signal based on the stored moving speed and moving direction. In this case, the frequency f can be expressed by f≈f0 (c + V · cos θ) / c. Here, f0 is a known frequency between communication devices, V is a moving speed, θ is an angle between the moving direction and the direction between communication devices, and c is the speed of light. One communication device compensates for a timing error to cancel the Doppler shift amount based on the frequency received from the other communication device and the calculated frequency. Thereby, even when the moving speed of the moving body is high, the time measurement error can be obtained with high accuracy.

  In the tenth aspect, the first signal and the second signal are known signals for generating information related to the position of the moving body between the communication devices. Thereby, a required signal can be reliably transmitted / received between communication apparatuses.

  In the eleventh aspect, the first signal and the second signal include an identifier unique to the transmission source of the first signal. For example, when one communication device is mounted on a moving body (for example, a vehicle) and a signal is transmitted from a large number of vehicles, the other communication device and the one communication device may receive a signal from which vehicle. Can be determined by the identifier, and information regarding the positions of a large number of moving objects can be obtained with high accuracy.

  In the twelfth aspect, at least two communication devices (for example, a first communication device and a second communication device) are provided in addition to the communication device mounted on the mobile body. One communication device stores position information of each communication device (first communication device and second communication device) other than the communication device mounted on the mobile body. For example, when one communication device is mounted on a moving body, the one communication device stores position information of communication devices other than itself (the first communication device and the second communication device). One communication device generates distance information (for example, distance) from each of the first communication device and the second communication device of the mobile body, and based on the generated distance information and the stored position information, the position information of the mobile body Is generated. For example, when the distance from the first communication device of the mobile body is L1, and the distance from the second communication device is L2, the position (position information) of the mobile body is centered on the positions of the first communication device and the second communication device. Can be obtained as intersections of circles (or spheres) having radii L1 and L2, respectively. In this case, when the moving body is a vehicle or the like and the road to be traveled is known, the position of the moving body can be specified as the intersection of the road surface and the circle (or sphere). In addition, even when one communication apparatus is not mounted on the moving body, the position information of the moving body can be generated in the same manner.

  In the thirteenth invention, one communication device stores road shape information of a moving area of a moving body, and generates position information of the moving body using the stored road shape information. For example, one communication device identifies a virtual traveling surface of a mobile object based on road shape information. One communication device identifies a circle (or sphere) centered on the position of a pair of communication devices (that is, the first communication device and the second communication device), and the identified circle (or sphere) and travel surface The position information is generated by specifying the intersecting line as the position of the moving body. Thereby, the position of a mobile body can be pinpointed with high precision by installing two communication apparatuses.

  In the fourteenth invention, one communication device stores the height information of the position of the communication device mounted on the moving body, and generates the position information of the moving body using the stored height information. By using the height information, the position of the moving body can be specified with higher accuracy.

  In the present invention, even if the time between communication devices is not synchronized, information (distance information) regarding the position of the moving object can be obtained with high accuracy.

Embodiment 1
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is a schematic diagram showing an example of the configuration of the position information generation system according to the present invention, FIG. 2 is a block diagram showing an example of the configuration of the in-vehicle device 100, and FIG. 3 shows an example of the configuration of the roadside device 200. FIG. The position information generation system includes an in-vehicle device 100 and a roadside device 200.

  The in-vehicle device 100 constitutes a road-vehicle communication system (position information generation system) with the roadside device 200. As will be described later, the in-vehicle device 100 transmits a predetermined signal (first signal) to the roadside device 200 (specifically, the first communication unit 210 and the second communication unit 220), and the roadside device 200 (specifically). Specifically, the distance (distance information) from the first communication unit 210 of the in-vehicle device 100 by receiving a predetermined signal (second signal) transmitted by the first communication unit 210 and the second communication unit 220). While calculating L1, the distance (distance information) L2 from the 2nd communication part 220 of the vehicle equipment 100 is calculated. The in-vehicle device 100 generates position information by specifying an intersection of circles (or spheres) around the positions of the first communication unit 210 and the second communication unit 220 as its own position.

  The in-vehicle device 100 includes a communication unit 10, a positioning unit 20, a storage unit 30, a control unit 40, a time correction unit 50, a propagation time calculation unit 60, a distance calculation unit 70, a position specifying unit 80, and the like.

  The roadside device 200 includes a first communication unit 210 having a clock 211, a second communication unit 220 having a clock 221, a control unit 230, a time shift calculation unit 240, a Doppler shift amount calculation unit 250, a storage unit 260, and the like. ing.

  First, the in-vehicle device 100 will be described. The control unit 40 controls the operation of the onboard device 100 as a whole.

  The communication unit 10 includes a communication function for performing communication with the roadside device 200, for example, in the frequency band of the VHF / UHF band. The communication unit 10 includes a crystal oscillator that generates a reference clock signal, a timekeeping mechanism such as a clock 11 that operates based on the reference clock signal (or may be a timer or a counter), a modulation circuit, a demodulation circuit, and the like. Is transmitted to the roadside device 200. The communication unit 10 outputs the signal transmission time to the control unit 40.

  FIG. 4 is an explanatory diagram illustrating an example of a data structure included in a signal transmitted by the in-vehicle device 100. The signal (first signal) transmitted by the in-vehicle device 100 is information related to the position of the in-vehicle device 100 (for example, the distance from the first communication unit 210 and the second communication unit 220 of the roadside device 200 of the in-vehicle device 100, the in-vehicle device. 100 position, etc.) to be generated, and repeatedly transmitted at appropriate intervals. As shown in FIG. 4, the signal transmitted by the in-vehicle device 100 is, for example, a pilot signal indicating that it is a signal for generating information on a position, an in-vehicle device ID for identifying the in-vehicle device 100 as a transmission source, Data such as transmission time information indicating the transmission time of the signal is included. The transmission time information may not be included. The pilot signal is a known signal between the in-vehicle device 100 and the roadside device 200. Thereby, it can be seen that the roadside device 200 is a signal for generating information related to the position of the in-vehicle device 100.

  Further, the communication unit 10 receives a signal transmitted by the roadside device 200 (first communication unit 210, second communication unit 220), demodulates the received signal, and extracts original information included in the signal. The communication unit 10 calculates a signal reception time and outputs the calculated reception time to the control unit 40.

  FIG. 5 is an explanatory diagram illustrating an example of a data structure included in a signal transmitted by the roadside device 200. The signal (second signal) transmitted by the roadside device 200 is transmitted to the vehicle-mounted device 100 in order to generate information regarding the position of the vehicle-mounted device 100, and the above-described signal (first signal) is transmitted from the vehicle-mounted device 100. ) Is received and transmitted after predetermined processing. As shown in FIG. 5, the signal transmitted by the roadside device 200 is, for example, a pilot signal indicating that it is a signal for generating position information, the first communication unit 210 of the roadside device 200 that is the transmission source, The communication unit ID for identifying which of the two communication units 220, the transmission time information indicating the transmission time of the signal, and which of the in-vehicle devices 100 is a signal corresponding to the signal transmitted from the in-vehicle device 100. It includes data such as a vehicle-mounted device ID for recognition, reception time information indicating a reception time when a signal transmitted by the vehicle-mounted device 100 is received, and position information indicating the positions of the first communication unit 210 and the second communication unit 220. . The pilot signal is a known signal between the in-vehicle device 100 and the roadside device 200. Thereby, it turns out that the onboard equipment 100 is a signal for producing | generating the information regarding the position of the onboard equipment 100. FIG.

  FIG. 6 is an explanatory diagram illustrating an example of calculating a signal reception time. FIG. 6A shows an example of a pilot signal of the signal (second signal) transmitted by the first communication unit 210 or the second communication unit 220 of the roadside device 200, and FIG. It is a replica signal for performing stored correlation processing (pattern matching). FIG. 6C is a received signal when the signal (second signal) transmitted from the first communication unit 210 or the second communication unit 220 of the roadside device 200 is received by the communication unit 10 of the in-vehicle device 100. . As shown in FIG. 6C, the communication unit 10 samples the received signal at a predetermined time interval, and measures the time when the sampled waveform and the waveform of the replica signal match as the received time.

  The positioning unit 20 includes a vehicle speed sensor 21, a distance meter 22, a gyro sensor 23, and the like, and measures a traveling speed, a traveling distance, a traveling direction, and the like of a vehicle on which the in-vehicle device 100 is mounted. The positioning result is temporarily stored in the storage unit 30.

  The storage unit 30 is a replica signal of a pilot signal, a processing result processed in the vehicle-mounted device 100 under the control of the control unit 40, information received via the communication unit 10, and the installation positions of the communication units 210 and 220 of the roadside device 200 Alternatively, the distance is stored. In addition, the structure which memorize | stores the information regarding the roadside machine 200 previously in the memory | storage part 30 may be sufficient, and the structure which receives and memorize | stores from the apparatus other than the roadside machine 200 or the roadside machine 200 as needed may be sufficient.

  The time correction unit 50 detects a time lag between the in-vehicle device 100 and the roadside device 200 measured by the roadside device 200 (more specifically, the degree of time advance between the timepiece 11 and the timepiece 211 or the timepiece 221 or Based on the degree of delay, that is, the error of the reference clock), the time lag of the timepiece 11 of the in-vehicle device 100 is corrected. It is not necessary to synchronize the timepiece 11 of the in-vehicle device 100 and the timepieces 211 and 221 of the roadside device 200 at the same time.

In general, the reference clock of the timepiece 11 mounted on the in-vehicle device 100 has a relatively large error, and has an accuracy of about 10 ⁻⁵ to 10 ⁻⁶ as an example. On the other hand, for the reference clocks of the clocks 211 and 221 provided in the roadside device 200, the roadside device 200 can use, for example, a method of extracting a clock from a GPS satellite. The accuracy is higher than that of the reference clock, and as an example, it is possible to have an accuracy of about 10 ⁻⁸ to 10 ⁻⁹ . In addition, since the degree of advancement or delay of the reference clock changes with the passage of time or fluctuates according to changes in the ambient temperature, correction in real time is necessary. A method for calculating the time lag will be described later.

  The propagation time calculation unit 60 includes the time until the signal (first signal) transmitted by the in-vehicle device 100 is received by the roadside device 200 and the signal (second signal) transmitted by the roadside device 200 as the on-vehicle device 100. The propagation time T, which is the sum of the time until the signal is received, is calculated.

  FIG. 7 is an explanatory diagram illustrating an example of calculating a propagation time of a signal between the in-vehicle device 100 and the roadside device 200. As illustrated in FIG. 7, the in-vehicle device 100 transmits a first signal including the first transmission time ta1 to the roadside device 200 at time ta1. The roadside device 200 receives the first signal and calculates a first reception time tb1. When the roadside device 200 transmits the second signal to the vehicle-mounted device 100 at time tb2, the roadside device 200 transmits the first signal from the first reception time tb1 to the second transmission time tb2, which is the transmission time of the second signal. Time information relating to time is included in the second signal and transmitted. Here, the time information may be the first reception time tb1 and the second transmission time tb2 itself, or may be an elapsed time from the first reception time tb1 to the second transmission time tb2. The in-vehicle device 100 receives the second signal and calculates a second reception time ta2. The in-vehicle device 100 calculates the signal propagation time T by T = ta2-ta1- (tb2-tb1). Thereby, even when the time is not synchronized between the in-vehicle device 100 and the roadside device 200 (for example, the time tb1 is the time tb1 ′ + α in the in-vehicle device 100 and the time tb2 is the time in the in-vehicle device 100. tb2 ′ + α and the time synchronization deviation α is unknown), the time synchronization deviation (α) is canceled out, and the signal propagation time can be obtained with high accuracy.

  The distance calculation unit 70 calculates the distance from the first communication unit 210 and the second communication unit 220 of the in-vehicle device 100 based on the propagation time calculated by the propagation time calculation unit 60. For example, when the propagation time of a signal between the in-vehicle device 100 and the first communication unit 210 is T1, if the in-vehicle device 100 can be regarded as almost stationary, the first communication unit 210 of the in-vehicle device 100 The distance L1 can be obtained by L1 = c × T1 / 2. Here, c is the speed of light. Similarly, when the propagation time of the signal between the in-vehicle device 100 and the second communication unit 220 is T2, if the in-vehicle device 100 can be regarded as almost stationary, the second communication unit 220 of the in-vehicle device 100 The distance L2 can be obtained by L2 = c × T2 / 2.

  When the in-vehicle device 100 is moving, the distance can be calculated as follows. FIG. 8 is an explanatory diagram showing an example of calculating the distance when the in-vehicle device 100 is moving. As shown in FIG. 8, when a vehicle equipped with the vehicle-mounted device 100 is traveling on a substantially straight road, the first communication unit 210 of the roadside device 200 is installed at a point away from the road by a required distance. To do. As shown in FIG. 8, it is assumed that the in-vehicle device 100 transmits a first signal at a first transmission time ta1 and receives a second signal at a second reception time ta2. The angle between the direction of movement of the vehicle-mounted device 100 at the first transmission time ta1 and the direction of the first communication unit 210 is θ1, and the direction of movement of the vehicle-mounted device 100 at the second reception time ta2 and the direction of the first communication unit 210. , The distance traveled by the vehicle-mounted device 100 from the first transmission time ta1 to the second reception time ta2, X, the signal propagation speed (light speed c), and the signal propagation time T1 {= ta2 If the propagation distance of the signal multiplied by -ta1- (tb2-tb1)} is L1, the distance Y1 from the first communication unit 210 of the vehicle-mounted device 100 at the second reception time ta2 is Y1 = (L1 · cos θ1 -X) / (cos θ1 + cos θ2). The distance from the 2nd communication part 220 of the vehicle equipment 100 can be calculated similarly.

  Note that when the vehicle-mounted device 100 travels in the direction of the first communication unit 210, θ1 = θ2 = 0 may be set. That is, in this case, the distance Y1 (or Y2) from the first communication unit 210 or the second communication unit 220 of the in-vehicle device 100 is a value obtained by adding the signal propagation speed T1 (or T2) to the signal propagation speed. It can be set to half of the value obtained by subtracting the moving distance X of the moving body from L1 (or L2). The distances Y1 and Y2 are distances at the second reception time point. Thereby, when the vehicle-mounted device 100 is moving, the distance from the first communication unit 210 and the second communication unit 220 of the vehicle-mounted device 100 can be accurately obtained regardless of the moving direction of the vehicle-mounted device 100.

  The position specifying unit 80 specifies the position of the in-vehicle device 100 based on the distance calculated by the distance calculating unit 70 and generates position information. For example, the distance from the 1st communication part 210 of the vehicle equipment 100 is set to L1, and the distance from the 2nd communication part 220 is set to L2. The position of the in-vehicle device 100 can be obtained as an intersection of circles or spheres whose radii are L1 and L2, respectively, centered on the positions of the first communication unit 210 and the second communication unit 220. In this case, when the road on which the in-vehicle device 100 is traveling is known, the position of the in-vehicle device 100 can be specified as the intersection of the road surface and the above-described circle or sphere.

  Next, the position of the in-vehicle device 100 is specified in consideration of the road shape information of the road on which the vehicle on which the in-vehicle device 100 is mounted, the height information of the mounting position of the in-vehicle device 100 (more precisely, the communication unit 10), and the like. An example will be described.

  FIG. 9 is an explanatory diagram showing the structure of road shape information. As shown in FIG. 9, the road shape information is configured by dividing a road into sections of a predetermined distance (for example, 20 m) by a plurality of nodes, and information such as distance, gradient, and curvature for each section. When the road is a straight line, nodes are set on one straight line along the road, and when the road is a curve, nodes (for example, two nodes) are set on a plurality of straight lines along the road. Thereby, even when the road is inclined by the curve, the plane determined by the two straight lines can be specified.

  The road shape information may be stored in the storage unit 30 in advance, or may be received from the roadside device 200 or an external device.

  FIG. 10 is an explanatory diagram illustrating an example of specifying the position of the in-vehicle device 100. In this case, the first communication unit 210 and the second communication unit 220 of the roadside machine 200 are installed with an appropriate distance (the separation distance is known). When the second signal is received from the first communication unit 210 and the second communication unit 220 at a certain point P1 on the road, the vehicle-mounted device 100 determines that the distance L11 from the first communication unit 210 and the second communication unit 220 And the intersection P1 of the circles or spheres having radii L11 and L21 around the positions of the first communication unit 210 and the second communication unit 220 can be obtained as the position of the in-vehicle device 100.

  On the other hand, the in-vehicle device 100 specifies a virtual traveling surface of the vehicle based on road shape information of a road (link: a road between intersections) on which the vehicle travels and height information of the on-vehicle device 100. When the road is a straight road, the traveling surface is a plane, and when the road is curved, the traveling surface is a curved surface.

  The in-vehicle device 100 specifies an intersection line that intersects the traveling surface with the above-described circle or sphere as the position of the in-vehicle device 100. Thereby, it becomes possible to specify the position of the vehicle-mounted device 100 with high accuracy only by providing the two first communication units 210 and the second communication unit 220.

  When the vehicle continues to travel and receives the second signal from the first communication unit 210 and the second communication unit 220 at the point P2 on the road, the in-vehicle device 100 is connected to the distance L12 from the first communication unit 210. The distance L22 from the second communication unit 220 is calculated, and the intersection P2 of the circles or spheres having radii L12 and L22 with the positions of the first communication unit 210 and the second communication unit 220 as the center is set as the position of the in-vehicle device 100. Can be sought.

  On the other hand, the in-vehicle device 100 specifies a virtual traveling surface of the vehicle based on road shape information of a road (link: a road between intersections) on which the vehicle travels and height information of the on-vehicle device 100.

  The in-vehicle device 100 specifies an intersection line that intersects the traveling surface with the above-described circle or sphere as the position of the in-vehicle device 100. Thereafter, by repeating the same operation, the in-vehicle device 100 can continue to specify the position of the in-vehicle device 100 with high accuracy each time the first signal is transmitted and the second signal is received. In this case, the width of the running surface corresponds to the lane width (or road width in the case of multiple lanes), but it is considered that the vehicle runs almost in the center of the lane, so the error in the width direction of the running surface is acceptable. Is within.

  Thereby, the position of the vehicle equipment 100 can be specified with high accuracy by installing two communication units. In addition to the road shape information, the position information of the in-vehicle device 100 can be specified with higher accuracy by considering the height information of the in-vehicle device 100.

  In the above example, when the reception time of the second signal transmitted from the first communication unit 210 and the reception time of the second signal transmitted from the second communication unit 220 are different, the reception time The distance from the first communication unit 210 or the distance from the second communication unit 220 of the in-vehicle device 100 may be corrected in consideration of the distance traveled by the in-vehicle device 100 during the time difference.

  Next, the roadside machine 200 will be described. The control unit 230 controls the operation of the entire roadside machine 200.

  The first communication unit 210 has the same configuration as that of the communication unit 10 and includes a communication function for performing communication with the in-vehicle device 100 in the frequency band of the VHF / UHF band, for example. The first communication unit 210 includes a crystal oscillator that generates a reference clock signal, a timekeeping mechanism such as a clock 211 (or a timer or a counter) that operates based on the reference clock signal, a modulation circuit, a demodulation circuit, and the like. The signal transmitted from the machine 100 is received and a predetermined signal is transmitted to the vehicle-mounted machine 100. The data structure included in the signal transmitted by the first communication unit 210 is as shown in FIG. 5, and the calculation of the reception time of the signal transmitted by the in-vehicle device 100 is the same as in the example of FIG.

  The second communication unit 220 has the same configuration and function as the first communication unit 210.

  The time shift calculation unit 240 calculates the advance degree or the delay degree (time measurement error) of the timepiece 11 of the in-vehicle device 100 with respect to the timepiece 211 and the timepiece 221. That is, the time shift calculation unit 240 calculates the error of the reference clock. The control unit 230 transmits the calculated time difference to the in-vehicle device 100 through the first communication unit 210 and the second communication unit 220.

  Hereinafter, a method for calculating the time lag will be described. The in-vehicle device 100 (communication unit 10) receives a signal including the known frequency component between the in-vehicle device 100 and the roadside device 200 (may be the first signal described above or a signal for reference clock correction). It transmits to the roadside machine 200. The reference clock correction signal is not limited to a signal used only for reference clock correction, and may be a signal used for reference clock correction and other purposes. The roadside device 200 (the first communication unit 210 and the second communication unit 220) extracts the frequency component of the received signal, and based on the difference between the extracted frequency component and a previously known frequency component, the time measurement error of the timepiece 11 Measure. For example, when the known frequency is 1 GHz and the frequency component extracted by the roadside device 200 is 1.000001 GHz, it can be seen that the timepiece 11 of the in-vehicle device 100 is 1 ppm faster than the timepiece 211 or the timepiece 221 of the roadside device 200. Thereby, the advance degree or delay degree of the timepiece (reference clock) between the timepiece 11 of the in-vehicle device 100 and the timepieces 211 and 221 of the roadside device 200 can be accurately measured.

  Note that, as a method of extracting a frequency component included in a signal, for example, by obtaining a correlation degree of a symbol within a guard interval included in the signal, it is possible to detect a symbol timing and obtain a frequency.

  As another calculation example, the time length of the signal can also be used. The in-vehicle device 100 (communication unit 10) transmits a signal of a known time length between the in-vehicle device 100 and the roadside device 200 (which may be the first signal described above or a signal for reference clock correction). To the machine 200. The roadside device 200 (the first communication unit 210, the second communication unit 220) extracts the time length of the received signal, and based on the difference between the extracted time length and a previously known time length, the time measurement error of the timepiece 11 Measure. For example, when the known time length is 10 milliseconds and the time length extracted by the roadside device 200 is 10 nanoseconds longer, the timepiece 11 of the in-vehicle device 100 may be 1 ppm later than the timepiece 211 or the timepiece 221 of the roadside device 200. Recognize. Thereby, the advance degree or delay degree of the timepiece (reference clock) between the timepiece 11 of the in-vehicle device 100 and the timepieces 211 and 221 of the roadside device 200 can be accurately measured.

  When the in-vehicle device 100 is traveling at a high speed, the Doppler shift amount calculation unit 250 calculates the amount of frequency fluctuation due to the influence of the Doppler shift. The Doppler shift amount calculation unit 250 acquires the moving speed and moving direction of the in-vehicle device 100, and calculates the frequency of the signal based on the acquired moving speed and moving direction. What is necessary is just to acquire the moving speed and moving direction of the vehicle equipment 100 by including in the signal which the vehicle equipment 100 transmits. The frequency f calculated by the Doppler shift can be expressed by f≈f0 (c + V · cos θ) / c. Here, f0 is a known frequency included in the signal transmitted by the in-vehicle device 100, V is the moving speed of the in-vehicle device 100, θ is the moving direction of the in-vehicle device 100, and the direction of the first communication unit 210 or the second communication unit 220. And c is the speed of light. Here, θ is 0 degree when the in-vehicle device 100 is directed to the first communication unit 210 or the second communication unit 220.

  When the influence by the Doppler shift cannot be ignored, the time shift calculation unit 240 compensates the calculated time shift based on the frequency f calculated by the Doppler shift amount calculation unit 250. That is, if the known frequency is f0, the frequency calculated by the Doppler shift is f, and the frequency extracted from the signal is f1, the frequency when the influence of the Doppler shift is canceled, that is, the signal transmitted by the in-vehicle device 100 is included. The frequency can be obtained by f0 × f1 / f, and the deviation of the reference clock can be obtained based on this. Thereby, even if it is a case where the moving speed of the vehicle equipment 100 is quick, a time measurement error can be calculated | required accurately.

  The storage unit 260 includes a replica signal of the pilot signal, a processing result processed in the roadside device 200 by the control of the control unit 230, information received via the first communication unit 210 and the second communication unit 220, and the first communication unit 210. In addition, the installation position or the separation distance of the second communication unit 220 is stored.

  Next, the operation of the in-vehicle device 100 will be described. FIG. 11 is a flowchart showing the processing procedure of the in-vehicle device 100. Note that the processing of the in-vehicle device 100 may be configured by a dedicated hardware circuit, or may be configured to execute a computer program having a predetermined processing procedure.

  The control unit 40 transmits the first signal to the roadside device 200 at an arbitrary timing (timing that requires information on the position of the in-vehicle device 100) (S11), measures the moving distance (S12), and determines the moving direction. Measure (S13). The control unit 40 determines whether or not the second signal is received from the roadside device 200 (S14). If the second signal is not received (NO in S14), the control unit 40 continues the processing from step S12.

  When the second signal is received from the roadside device 200 (YES in S14), that is, when signals are received from the first communication unit 210 and the second communication unit 220, the control unit 40 extracts information included in the signal. Then, it is determined whether or not correction of the time lag is necessary (S15). When it is necessary to correct the time lag (YES in S15), the control unit 40 corrects the time (reference clock) according to the time lag measured by the roadside device 200 (S16).

  When the correction of the time lag is not necessary (NO in S15), the control unit 40 performs the process of step S17 described later without performing the process of step S16. The control unit 40 receives the time until the first signal transmitted from the communication unit 10 is received by the first communication unit 210 and the second signal transmitted by the first communication unit 210 at the communication unit 10. The propagation time which is the sum of the time until is calculated (S17). Note that the propagation time is similarly calculated for the second communication unit 220. The control unit 40 calculates the distance from the first communication unit 210 and the second communication unit 220 of the in-vehicle device 100 based on the calculated propagation time (S18).

  Based on the calculated distance, the control unit 40 is an intersection of a circle or a sphere centered on the positions of the first communication unit 210 and the second communication unit 220, road shape information on which the vehicle on which the vehicle-mounted device 100 is mounted, The position of the in-vehicle device 100 is specified based on the height information of the mounting position of the device 100 (S19). The control unit 40 generates the calculated distance, the specified position, and the like as information related to the position of the in-vehicle device 100. The control unit 40 determines whether or not there is an instruction to end the process (S20). If there is no end instruction (NO in S20), the process continues from step S11. finish.

Embodiment 2
In the first embodiment, the in-vehicle device 100 transmits the first signal to the roadside device 200, and receives the second signal transmitted from the roadside device 200, thereby generating information related to the position of the on-vehicle device 100. However, the present invention is not limited to this, and the roadside device transmits the first signal to the in-vehicle device 100, the second signal transmitted by the in-vehicle device 100 is received by the roadside device, and the vehicle is mounted on the roadside device. Information about the position of the machine 100 can also be generated.

  FIG. 12 is a block diagram illustrating an example of the configuration of the roadside machine 300 according to the second embodiment. The roadside device 300 includes a first communication unit 210 including a clock 211, a second communication unit 220 including a clock 221, a storage unit 260, a control unit 230, a time shift calculation unit 240, a Doppler shift amount calculation unit 250, and a time correction unit 310. , A propagation time calculation unit 320, a distance calculation unit 330, a position specifying unit 340, and the like.

  The time correction unit 310, the propagation time calculation unit 320, the distance calculation unit 330, and the position specification unit 340 are respectively the time correction unit 50, the propagation time calculation unit 60, and the distance calculation unit 70 provided in the in-vehicle device 100 of the first embodiment. The configuration is the same as that of the position specifying unit 80. Therefore, in the second embodiment, the in-vehicle device 100 does not need to include the time correction unit 50, the propagation time calculation unit 60, the distance calculation unit 70, the position specifying unit 80, and the like. Moreover, the 1st communication part 210, the 2nd communication part 220, the memory | storage part 260, the control part 230, the time shift calculation part 240, and the Doppler shift amount calculation part 250 are the same as that of the case of the roadside machine 100 of Embodiment 1. FIG. .

  The roadside device 300 (the first communication unit 210 and the second communication unit 220) transmits a predetermined signal (first signal) to the in-vehicle device 100, and the predetermined signal (the communication unit 10) transmitted by the predetermined signal ( (Distance information) L1 from the first communication unit 210 of the in-vehicle device 100 and the distance (distance information) L2 from the second communication unit 220 of the in-vehicle device 100 by receiving the second signal). Is calculated. The roadside device 300 generates position information by specifying, as the position of the in-vehicle device 100, an intersection of circles or spheres having radii L1 and L2 with the positions of the first communication unit 210 and the second communication unit 220 as the center. Since other operations are the same as those in the first embodiment, description thereof is omitted.

  In addition, the structure which performs the process which pinpoints the position of vehicle equipment after performing transmission / reception of a predetermined signal between vehicle equipment and a roadside machine with a device different from a roadside machine may be sufficient.

Embodiment 3
In the first and second embodiments described above, the vehicle-mounted device 100 itself may be configured to have an autonomous vehicle presence position measuring function using GPS or the like. In this case, the in-vehicle device 100 can exchange information about the position of the own vehicle measured autonomously with the in-vehicle devices of other vehicles traveling in the vicinity. By transmitting and receiving mutual position information between the in-vehicle devices 100, the in-vehicle device 100 of each vehicle is how many vehicles exist around the own vehicle, how close the vehicle is, and so on. Can be grasped, and it becomes possible to support the driver's safe driving.

  In such an apparatus or system, the vehicle position that each vehicle autonomously recognizes may have an error that is greater than or equal to a predetermined value. If there is an error in the location information that exceeds a certain level, it may be misunderstood that the other vehicle that received the location information is actually separated by some distance, but this increases traffic safety. May not be suitable for the purpose. Therefore, by adopting the configuration in which the roadside devices 200 and 300 shown in the first and second embodiments are arranged, the position of the in-vehicle device 100 is specified by both the in-vehicle device 100 and the roadside device 300, and the in-vehicle device 100 is When the roadside device 300 intercepts the position information being transmitted and received, and the vehicle location recognized by the roadside device 300 and the vehicle location recognized by the vehicle-mounted device 100 itself have an error greater than or equal to a predetermined value, the roadside device 300 Can send warning information to the in-vehicle device 100.

  The above-mentioned warning information includes, for example, information on the position of the vehicle measured by the roadside device 300 and information that can know how much the error is, and the autonomous positioning function of the in-vehicle device 100 itself. It is desirable to be able to immediately grasp that there is a problem with Furthermore, warning information is also sent to the in-vehicle device 100 of the vehicle traveling around the vehicle having a problem with the autonomous positioning function, and there is an error in the position information of the specific vehicle transmitted / received by inter-vehicle communication. You can also let them know. As described above, in the present invention, positioning by the roadside device 300 can be used as a complement to the autonomous positioning function of the vehicle.

  As described above, in the present invention, even when the time of the vehicle-mounted device and the time of the roadside device are not the same time (that is, when the time is not synchronized), By transmitting and receiving the first signal and the second signal between the two, it is possible to cancel out the synchronization of time and obtain information on the position of the vehicle-mounted device with high accuracy.

  In the above-described embodiment, when the signal transmitted by the in-vehicle device is received by the roadside device, if the difference between the transmission time of the received signal and the reception time of the signal is greater than a predetermined threshold, It can also be configured such that a signal that prompts the vehicle-mounted device to transmit a signal for correcting the reference clock is transmitted from the roadside device, assuming that the clock (reference clock) is abnormal.

  In the above-described embodiment, the roadside unit includes the communication unit. However, each communication unit may be configured as a separate communication device. In addition, a control unit, a time shift calculation unit, a Doppler shift amount calculation unit, a time correction unit, a propagation time calculation unit, a distance calculation unit, a position specifying unit, a storage unit, and the like of the roadside machine may be configured in any communication unit. it can. Moreover, it can replace with a roadside machine and can also use other apparatuses, such as a signal controller.

  In the above-described embodiment, the roadside device includes the Doppler shift amount calculation unit 250 and the time lag calculation unit 240. However, the present invention is not limited to this, and a configuration provided in the in-vehicle device 100 may be employed. . In this case, the in-vehicle device 100 acquires the moving speed and moving direction of the vehicle, and stores the acquired moving speed and moving direction. The in-vehicle device 100 receives a time measurement error (for example, a clock shift for time measurement, a difference with a previously known frequency or time length, or a frequency or time length itself) from the roadside device. For example, when using a frequency as a time measurement error, the in-vehicle device 100 calculates a Doppler shift amount (frequency) of a signal based on the stored moving speed and moving direction. The frequency f calculated by the Doppler shift can be expressed by f≈f0 (c + V · cos θ) / c. Here, f0 is a known frequency included in the signal transmitted by the in-vehicle device 100, V is the moving speed of the in-vehicle device 100, θ is the moving direction of the in-vehicle device 100, and the direction of the first communication unit 210 or the second communication unit 220. And c is the speed of light. θ is 0 degree when the in-vehicle device 100 is directed to the first communication unit 210 or the second communication unit 220. The in-vehicle device 100 compensates the time measurement error to cancel the Doppler shift amount based on the frequency received from the roadside device and the calculated frequency. Thereby, even when the moving speed of the moving body is high, the time measurement error can be obtained with high accuracy.

  According to the present invention, since the position of the in-vehicle device can be obtained with high accuracy, by using the present invention, for example, the display information of the traffic signal ahead is received by the in-vehicle device, and the intersection information is obtained based on the received display information. It is possible to determine with high accuracy whether it is possible to stop safely in front of the vehicle, or whether it is possible to safely pass through the intersection, and the driver can be alerted by voice according to the determination result. . In addition, it is possible to determine with high accuracy whether or not the vehicle can safely pass through the intersection based on the display information of the traffic signal received by the vehicle-mounted device, and to perform vehicle brake control according to the determination result. Accidents can be prevented and traffic safety can be improved.

  In the above embodiment, the time lag is calculated and the time lag is corrected. However, the present invention is not limited to this, and the time measuring means may be constituted by a timer or a counter in addition to the clock. It is also possible to calculate the deviation of the count values and correct the deviation of the count values. In other words, the time lag includes these count values.

  In the above-described embodiment, the in-vehicle device has been described as an example. However, the in-vehicle device is not limited to the in-vehicle device, and a mobile communication device (for example, a mobile phone or a communication function) carried by a moving person such as a pedestrian A PDA or a music / video playback device, a notebook personal computer, or the like).

  In the above-described embodiment, the roadside machine is configured to include two communication units. However, the configuration is not limited thereto, and the number of communication units may be 3, 4 or the like. As a result, a plurality of rotating hyperboloids depending on the distance difference between the in-vehicle device and each communication unit can be specified, and the position of the in-vehicle device can be obtained as an intersection of the rotating hyperboloids.

  The disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic diagram which shows an example of a structure of the positional information generation system which concerns on this invention. It is a block diagram which shows an example of a structure of a vehicle equipment. It is a block diagram which shows an example of a structure of a roadside machine. It is explanatory drawing which shows the example of the data structure contained in the signal which a vehicle equipment transmits. It is explanatory drawing which shows the example of the data structure contained in the signal which a roadside machine transmits. It is explanatory drawing which shows the example of calculation of the reception time of a signal. It is explanatory drawing which shows the example of calculation of the propagation time of the signal between vehicle equipment and a roadside machine. It is explanatory drawing which shows the example of calculation of the distance in case an onboard equipment is moving. It is explanatory drawing which shows the structure of road shape information. It is explanatory drawing which shows the example which pinpoints the position of vehicle equipment. It is a flowchart which shows the process sequence of a vehicle equipment. It is a block diagram which shows an example of a structure of the roadside machine of Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Communication part 11 Clock 20 Positioning part 21 Vehicle speed sensor 22 Distance meter 23 Gyro sensor 30, 260 Storage part 40, 230 Control part 50, 310 Time correction part 60, 320 Propagation time calculation part 70, 330 Distance calculation part 80, 340 Position Specific unit 100 In-vehicle device 200, 300 Roadside device 210 First communication unit 220 Second communication unit 211, 221 Clock 240 Time difference calculation unit 250 Doppler shift amount calculation unit

Claims (19)

A position information generating system comprising at least two communication devices including a communication device mounted on a mobile body, and generating information related to the position of the mobile body by transmitting and receiving a predetermined signal between the communication devices,
One communication device is
Transmitting means for transmitting the first signal to another communication device;
Receiving means for receiving a second signal transmitted by the other communication device;
The other communication device is:
Receiving means for receiving the first signal;
Transmitting means for transmitting the second signal including time information relating to a time from a first reception time point when the first signal is received by the receiving means to a second transmission time point of the second signal. ,
The one communication device is:
A communication device other than the communication device on which the moving body is mounted based on the second reception time point when the second signal is received, the first transmission time point when the first signal is transmitted, and the time information. A position information generating system, further comprising generating means for generating distance information from the device. The one communication device is:
Provided with a distance acquisition means for acquiring the moving distance of the moving body,
The generating means includes
The distance information of the mobile body is generated based on the distance traveled by the mobile body from the first transmission time point to the second reception time point. Location information generation system described in 1. The one communication device is:
Comprising an azimuth acquiring means for acquiring the moving azimuth of the moving object;
The generating means includes
3. The distance information of the mobile body is generated based on the direction in which the mobile body has moved between the first transmission time and the second reception time. Location information generation system described in 1. Each communication device
It has a clocking means that operates with a reference clock for clocking,
The timing error of the timing means of the other communication device is smaller than the timing error of the timing means of the one communication device,
The other communication device is:
Measuring means for measuring a time error of the time measuring means of the one communication device;
Transmission means for transmitting the measurement result measured by the measurement means to the one communication device,
The one communication device is:
Receiving means for receiving the measurement result;
The correction means which correct | amends the time from the said 1st transmission time to the 2nd reception time based on the received measurement result, These are equipped with these. The Claim 1 thru | or 3 characterized by the above-mentioned. Position information generation system. The one communication device is:
A reference clock correction signal including a known frequency component between communication devices is configured to be transmitted to the other communication device,
The other communication device is:
An extraction means for extracting a frequency component of the reference clock correction signal;
The measuring means includes
5. The position information generation system according to claim 4, wherein a time error of the time measuring means of the one communication device is measured based on the frequency component extracted by the extracting means. The one communication device is:
A reference clock correction signal having a known time length between communication devices is configured to be transmitted to the other communication device,
The other communication device is:
An extraction means for extracting a time length of the reference clock correction signal;
The measuring means includes
5. The position information generating system according to claim 4, wherein a time error of the time measuring means of the one communication device is measured based on the time length extracted by the extracting means. The one communication device is:
Transmitting the first signal including a known frequency component or the first signal of a known time length;
The other communication device is:
An extraction means for extracting a frequency component or time length of the first signal;
The measuring means includes
5. The position information generating system according to claim 4, wherein a time error of the time measuring means of the one communication device is measured based on the frequency component or time length extracted by the extracting means. The other communication device is:
Acquisition means for acquiring the moving speed and moving direction of the moving body;
Calculating means for calculating the Doppler shift amount of the signal based on the moving speed and moving direction acquired by the acquiring means;
The position according to any one of claims 4 to 7, further comprising: a compensation unit that compensates a time error measured by the measurement unit so as to cancel out the Doppler shift amount calculated by the calculation unit. Information generation system. The one communication device is:
Storage means for storing the moving speed and moving direction of the moving body;
A calculating means for calculating a Doppler shift amount of the signal based on the stored moving speed and moving direction;
5. Compensation means for compensating a time error of the time measuring means based on a measurement result received by the receiving means to cancel out the Doppler shift amount calculated by the calculating means. The position information generation system according to any one of 7. The first signal and the second signal are:
The position information generation system according to claim 1, wherein the position information generation system is a known signal between communication apparatuses. The first signal and the second signal are:
The position information generation system according to claim 1, further comprising an identifier unique to a transmission source of the first signal. In addition to the communication device mounted on the mobile body, at least two communication devices are provided,
The one communication device is:
Comprising storage means for storing position information of each communication device other than the communication device mounted on the mobile body;
The generating means includes
It is configured to generate distance information from each communication device of the mobile body,
12. The apparatus according to claim 1, further comprising a position information generation unit configured to generate position information of the moving body based on the distance information generated by the generation unit and the stored position information. The location information generation system described. The one communication device is:
Comprising storage means for storing road shape information of the moving area of the moving body;
The position information generating means includes
The position information generation system according to claim 12, wherein the position information of the moving body is generated using the stored road shape information. The one communication device is:
Comprising storage means for storing height information of the position of the communication device mounted on the mobile body;
The position information generating means includes
The position information generation system according to claim 12 or 13, wherein the position information of the moving body is generated using the stored height information. A position information generating device that transmits and receives a predetermined signal to and from a communication device to generate information about its own position,
Transmitting means for transmitting a first signal to the communication device;
The second signal including time information relating to a time from a first reception time at which the communication device receives the first signal to a second transmission time of a second signal transmitted by the communication device is transmitted to the communication device. Receiving means for receiving from the device;
Based on the second reception time when the second signal is received by the receiving means, the first transmission time when the first signal is transmitted, and time information, the distance information from the communication device is generated. A position information generating device comprising: a generating unit. A position information generation device that generates information related to the position of the mobile body by transmitting and receiving a predetermined signal to and from a communication device mounted on the mobile body,
Transmitting means for transmitting a first signal to the communication device;
The second signal including time information relating to a time from a first reception time at which the communication device receives the first signal to a second transmission time of a second signal transmitted by the communication device is transmitted to the communication device. Receiving means for receiving from the device;
Generating means for generating distance information to the moving body based on a second reception time point when the second signal is received by the reception means, a first transmission time point when the first signal is transmitted, and time information; A position information generating apparatus comprising: A computer program for causing a computer to generate information about its own position based on a first signal transmitted to a communication device and a second signal received from the communication device,
Calculating means for calculating a time from a first transmission time point when the first signal is transmitted to a second reception time point when the second signal is received;
Based on the calculated time and time information about the time from the first reception time at which the first signal is received by the communication device to the second transmission time at which the communication device transmits the second signal. A computer program that functions as generating means for generating distance information from the communication device. A computer program for causing a computer to generate information related to the position of the mobile body based on a first signal transmitted to a communication device mounted on the mobile body and a second signal received from the communication device,
Calculating means for calculating a time from a first transmission time point when the first signal is transmitted to a second reception time point when the second signal is received;
Based on the calculated time and time information regarding the time from the first reception time when the first signal is received by the communication device to the second transmission time when the second signal is transmitted by the communication device. A computer program which functions as a generating means for generating distance information to the body. A position information generation method for generating information on the position of the mobile body by transmitting and receiving a predetermined signal between at least two communication apparatuses including a communication apparatus mounted on the mobile body,
One communication device is
Sending the first signal to another communication device;
The other communication device is:
Receiving the first signal;
Transmitting the second signal including time information relating to a time from a first reception time point when the first signal is received to a second transmission time point of a second signal transmitted by the first signal to the one communication device; ,
The one communication device is:
Receiving the second signal;
A communication device other than the communication device on which the moving body is mounted based on the second reception time point when the second signal is received, the first transmission time point when the first signal is transmitted, and the time information. A position information generating method characterized by generating distance information from

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