Positioning system, on-vehicle device, host vehicle position identification program, roadside unit, and absolute position estimation program

Abstract

An on-vehicle device (8) comprises: a signal-receiving unit (8a) that receives a road-to-vehicle signal transmitted from each of a first roadside unit and a second roadside unit that face each other across a traffic lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the device itself and the first roadside unit, and a second pseudo-distance between the device itself and the second roadside unit, on the basis of a pseudo-distance candidate included in the road-to-vehicle signal; a roadside unit position estimation unit (8c) for estimating the position of the first roadside unit on the basis of the first pseudo-distance and estimating the position of the second roadside unit on the basis of the second pseudo-distance; a road shape estimation unit (8d) for estimating the road shape on the basis of the first roadside unit position and the second roadside unit position; and a positioning unit (8e) for identifying the position of the host vehicle on the basis of the first pseudo-distance, the second pseudo-distance and the road shape, upon applying a constraint to the first pseudo-distance and / or the second pseudo-distance according to the first pseudo-distance, the second pseudo-distance, the first roadside unit position, the second roadside unit position, and the road shape.

Description

Positioning system, on-board device, vehicle position identification program, roadside device, and absolute position estimation program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-032186, filed on March 4, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a positioning system, an in-vehicle device, a vehicle position specifying program, a roadside device, and an absolute position estimation program.

[0003] In positioning using GNSS (Global Navigation Satellite System) satellites, a problem arises when performing positioning in a space where GNSS signals transmitted from the GNSS satellites cannot be received, such as in a tunnel. To address this problem, for example, Patent Document 1 discloses a configuration for performing positioning in a space where GNSS signals transmitted from the GNSS satellites cannot be received, by including a GNSS positioning device, a vehicle speed detection device, a lateral ranging device, and a processing device that calculates the position of a vehicle based on at least one significant measurement value from the GPS positioning device, the vehicle speed detection device, and the lateral ranging device.

[0004] Japanese Patent Application Publication No. 11-211493

[0005] On the other hand, there is also a method that uses map matching technology to perform positioning in spaces where GNSS signals cannot be received. However, neither the method described in Patent Document 1 nor the method using map matching technology takes into consideration issues such as multipath and phasing caused by radio wave propagation in tunnels, and there is a problem that the positioning accuracy in tunnels decreases due to the influence of radio wave propagation. Furthermore, there is also a problem that it is necessary to prepare accurate maps and accurately install roadside units.

[0006] The first object of the present disclosure is to appropriately improve positioning accuracy by avoiding the influence of radio wave propagation, and the second object is to enable roadside devices to autonomously perform appropriate positioning assistance.

[0007] According to one aspect of the positioning system of the present disclosure, the system includes a roadside unit installed in a tunnel and an onboard unit mounted on a vehicle traveling in the tunnel, and performs road-to-vehicle communication between the roadside unit and the onboard unit. the on-board device includes: a signal receiving unit that receives road-to-vehicle signals transmitted from a first roadside device and a second roadside device that face each other across a lane; a pseudo-distance calculation unit that calculates a first pseudo-distance between the on-board device and the first roadside device and a second pseudo-distance between the on-board device and the second roadside device based on pseudo-distance candidates included in the road-to-vehicle signal; a roadside device position estimating unit that estimates a position of the first roadside device based on the first pseudo-distance calculated by the pseudo-distance calculation unit and estimates a position of the second roadside device based on the second pseudo-distance; a road shape estimating unit that estimates a road shape based on the positions of the first roadside device and the second roadside device; and a positioning unit that specifies the position of the on-board device based on the first pseudo-distance, the second pseudo-distance, the position of the first roadside device, the position of the second roadside device, and the road shape, and then restricts at least one of the first pseudo-distance and the second pseudo-distance.

[0008] According to one aspect of the present disclosure, the vehicle-mounted device is mounted on a vehicle traveling in a tunnel, and performs road-to-vehicle communication with a roadside device installed in the tunnel. the roadside device position estimation unit estimating a position of the first roadside device based on the first pseudo distance calculated by the pseudo distance calculation unit and estimating a position of the second roadside device based on the second pseudo distance; a roadside device position estimation unit estimating a road shape based on the positions of the first roadside device and the second roadside device; and a positioning unit estimating a position of the vehicle based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape, after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

[0009] According to a vehicle position identification program of one aspect of the present disclosure, the program includes a signal reception step of receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device that face each other across a lane to an onboard device that is mounted on a vehicle traveling in a tunnel and that performs road-to-vehicle communication with a roadside device installed in the tunnel; a pseudo-distance calculation step of calculating a first pseudo-distance between the vehicle and the first roadside device and a second pseudo-distance between the vehicle and the second roadside device based on candidates of pseudo-distances included in the road-to-vehicle signals; and a pseudo-distance calculation step of calculating a first pseudo-distance between the vehicle and the first roadside device and a second pseudo-distance between the vehicle and the second roadside device based on the first pseudo-distances calculated by the pseudo-distance calculation step. The system executes a roadside device position estimation procedure that estimates the position of a first roadside device and estimates the position of a second roadside device based on the second pseudo distance; a road shape estimation procedure that estimates the road shape based on the positions of the first roadside device and the second roadside device; and a positioning procedure that specifies the vehicle position based on the first pseudo distance, the second pseudo distance, and the road shape after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

[0010] According to one aspect of the present disclosure, a first pseudo-range between an on-vehicle device and a first roadside device and a second pseudo-range between the on-vehicle device and a second roadside device are calculated, and a constraint is imposed on at least one of the calculated first pseudo-range and second pseudo-range, and then the vehicle position is determined based on the first pseudo-range, the second pseudo-range, and the road shape. By imposing a constraint on at least one of the first pseudo-range and the second pseudo-range, it is possible to avoid a decrease in accuracy of the first pseudo-range and the second pseudo-range due to the influence of radio wave propagation, and it is possible to avoid the influence of radio wave propagation and appropriately improve positioning accuracy.

[0011] According to one aspect of the present disclosure, a positioning system includes a roadside device installed in a tunnel and an onboard device mounted on a vehicle traveling in the tunnel, and performs road-to-vehicle communication between the roadside device and the onboard device. The roadside device includes an absolute position estimation unit that estimates an absolute position based on a curvature estimated from a difference in distance between the roadside device and a first guide roadside device that is parallel to the roadside device, and a distance between an oncoming roadside device that faces the roadside device across a lane and a second guide roadside device that faces the first guide roadside device across a lane, the distance between the roadside device and the oncoming roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

[0012] According to one aspect of the present disclosure, a roadside device is installed in a tunnel and performs road-to-vehicle communication with an onboard device mounted on a vehicle traveling in the tunnel. The roadside device includes an absolute position estimation unit that estimates an absolute position based on a curvature estimated from a difference between the distance between the roadside device and a first guide roadside device that is parallel to the roadside device, and the distance between an oncoming roadside device that faces the roadside device across a lane and a second guide roadside device that faces the first guide roadside device across a lane, the distance between the roadside device and the oncoming roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

[0013] According to an absolute position estimation program of one aspect of the present disclosure, a roadside device that is installed in a tunnel and that performs road-to-vehicle communication with an onboard device mounted on a vehicle traveling in the tunnel is made to execute an absolute position estimation procedure that estimates an absolute position based on a curvature estimated from the difference in distance between the roadside device and a first guide roadside device that is parallel to the roadside device, and the distance between an opposing roadside device that faces the roadside device across a lane and a second guide roadside device that faces the first guide roadside device across a lane, the distance between the roadside device and the opposing roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

[0014] According to one aspect of the present disclosure, the roadside device is configured to estimate its absolute position. By autonomously estimating the absolute position, it is not necessary to prepare an accurate map or to accurately install the roadside device. By transmitting the estimated absolute position to the in-vehicle device, the roadside device can autonomously perform appropriate positioning assistance.

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 1 is a diagram showing the overall configuration of an embodiment, FIG. 2 is a diagram showing the connection of roadside devices, FIG. 3 is a diagram showing the connection of roadside devices, FIG. 4 is a functional block diagram showing the configuration of a local roadside device, FIG. 5 is a diagram explaining estimation of absolute position, FIG. 6 is a functional block diagram showing the configuration of an in-vehicle device, FIG. 7 is a diagram explaining calculation of pseudo distance, FIG. 8 is a flowchart showing vehicle detection processing performed by a guide roadside device (entrance side), FIG. 9 is a flowchart showing first periodic processing performed by a guide roadside device (entrance side), FIG. 10 is a flowchart showing second periodic processing performed by a guide roadside device (entrance side), FIG. 11 is a flowchart showing vehicle detection processing performed by a guide roadside device (exit side), FIG. 12 is a flowchart showing first periodic processing performed by a guide roadside device (exit side), and FIG. 13 is a flowchart showing calculation of pseudo distance by a guide roadside device (exit side). FIG. 14 is a flowchart showing the diagnostic information analysis processing performed by the guide roadside unit (exit side), FIG. 15 is a flowchart showing the initialization processing performed by the local roadside unit, FIG. 16 is a flowchart showing the steady-state processing performed by the local roadside unit, FIG. 17 is a flowchart showing the positioning processing performed by the on-board unit when entering a tunnel, FIG. 18 is a flowchart showing the health information analysis processing performed by the on-board unit when entering a tunnel, FIG. 19 is a flowchart showing the steady-state processing performed by the on-board unit while traveling through a tunnel, FIG. 20 is a flowchart showing the positioning processing performed by the on-board unit when exiting a tunnel, FIG. 21 is a flowchart showing the health information analysis processing performed by the on-board unit when exiting a tunnel, and FIG. 22 is a flowchart showing the diagnostic information transmission processing performed by the on-board unit when exiting a tunnel.

[0016] An embodiment will be described below with reference to the drawings. As shown in FIG. 1 , a guide roadside unit 2, local roadside units 61 to 6 n (corresponding to roadside units), and a guide roadside unit 3 are arranged in a row along the shape of one wall W1 forming a tunnel, while a guide roadside unit 4, local roadside units 71 to 7 n (corresponding to roadside units), and a guide roadside unit 5 are arranged in a row along the shape of the other wall W2. When vehicle A travels through a tunnel, guide roadside unit 2, local roadside units 61 to 6 n, and guide roadside unit 3 are installed on the driving lane side of vehicle A, and guide roadside unit 4, local roadside units 71 to 7 n, and guide roadside unit 5 are installed on the oncoming lane side of vehicle A. Positioning system 1 is configured to include guide roadside units 2 to 5, local roadside units 61 to 6 n and 71 to 7 n, and an on-board unit 8 installed in vehicle A.

[0017] The guide roadside units 2 and 4 are installed opposite each other across the lane at the entrance of the tunnel as seen from the traveling direction of vehicle A. The guide roadside units 3 and 5 are installed opposite each other across the lane at the exit of the tunnel as seen from the traveling direction of vehicle A.

[0018] The guide roadside units 2 to 5 are all installed in positions where they can see the GNSS satellites orbiting the sky, that is, in positions where they can receive GNSS signals transmitted from the GNSS satellites. The guide roadside units 2 to 5 each form a short-range communication area, and when vehicle A enters a short-range communication area, they perform road-to-vehicle communication by transmitting and receiving road-to-vehicle signals with the in-vehicle unit 8. Because the guide roadside units 2 to 5 are installed in positions where they can receive GNSS signals, they can autonomously determine their absolute positions and serve as a reference for absolute positions and time synchronization of the local roadside units 61 to 6 n and 71 to 7 n.

[0019] The guide roadside units 2 to 5 are also equipped with cameras that capture images of vehicles entering or exiting the tunnel, and transmit road-to-vehicle signals including captured image information to the in-vehicle unit 8. The guide roadside units 2 and 3 also transmit road-to-vehicle signals including health information indicating the status of the local roadside units 61 to 6 n to the in-vehicle unit 8. The guide roadside units 4 and 5 transmit road-to-vehicle signals including health information indicating the status of the local roadside units 71 to 7 n to the in-vehicle unit 8. The health information is, for example, information indicating whether the local roadside units 61 to 6 n and 71 to 7 n are operating normally.

[0020] 1, when vehicle A is traveling through a tunnel, a road-to-vehicle signal including imaging information and a road-to-vehicle signal including health information are transmitted from guide roadside unit 2 to onboard unit 8 when vehicle A enters the tunnel, and when vehicle A exits the tunnel, a road-to-vehicle signal including imaging information and a road-to-vehicle signal including health information are transmitted from guide roadside unit 3 to onboard unit 8. Note that in addition to the road-to-vehicle signals being transmitted from guide roadside units 2 and 3 on the driving lane side of vehicle A to onboard unit 8, road-to-vehicle signals may also be transmitted from guide roadside units 4 and 5 on the opposite lane side of vehicle A to onboard unit 8.

[0021] The local roadside units 61 to 6 n are arranged in parallel between guide roadside unit 2 and guide roadside unit 3. The local roadside units 71 to 7 n are arranged in parallel between guide roadside unit 4 and guide roadside unit 5. The local roadside units 61 to 6 n and the local roadside units 71 to 7 n are installed opposite each other across a lane. That is, the local roadside units 61 and 71 are installed opposite each other across a lane, and the local roadside units 6 n and 7 n are installed opposite each other across a lane. All of the local roadside units 61 to 6 n and 71 to 7 n are installed in positions where they cannot see the GNSS satellites, that is, in positions where they cannot receive the GNSS signals transmitted from the GNSS satellites. Like the guide roadside units 2 to 5, the local roadside units 61 to 6n, 71 to 7n each form a short-range communication area, and when vehicle A enters the short-range communication area, it transmits and receives road-to-vehicle signals to and from the in-vehicle unit 8 to perform road-to-vehicle communication.

[0022] As shown in FIG. 2, the guide roadside units 2 and 3 and the local roadside units 61 to 6 n are connected to each other so that data can be communicated via a data communication line 9, such as an optical fiber. The guide roadside units 2 and 3 perform data communication with the local roadside units 61 to 6 n via the data communication line 9, and determine whether or not the local roadside units 61 to 6 n are operating normally, for example, by determining whether or not there is a response to the transmission of a test signal. Similarly, as shown in FIG. 3, the guide roadside units 4 and 5 and the local roadside units 71 to 7 n are connected to each other so that data can be communicated via a data communication line 10, such as an optical fiber. The guide roadside units 4 and 5 perform data communication with the local roadside units 71 to 7 n via the data communication line 10, and determine whether or not the local roadside units 71 to 7 n are operating normally, for example, by determining whether or not there is a response to the transmission of a test signal.

[0023] The local roadside units 61 to 6n and 71 to 7n will be described below. Because the local roadside units 61 to 6n and 71 to 7n have the same configuration, the local roadside unit 61 will be described as a representative. When describing the local roadside unit 61 as a representative, the local roadside unit 71 corresponds to the opposing roadside unit, the guide roadside units 2 and 3 correspond to the first guide roadside unit, and the guide roadside units 4 and 5 correspond to the second guide roadside unit.

[0024] 4, the local roadside device 61 includes a distance measurement unit 61a, an RF signal transmission / reception unit 61b, an RF signal analysis unit 61c, a road shape estimation unit 61d, a positioning support information generation unit 61e, and an absolute position estimation unit 61f. Each of these units 61a to 61f is configured by a microcomputer having a CPU, ROM, RAM, I / O, etc., and is realized by control through software processing in which the CPU executes a computer program stored in a non-transient physical storage medium, or by control through hardware processing using a dedicated electronic circuit. The absolute position estimation unit 61f executes an absolute position estimation program.

[0025] The distance measurement unit 61a measures the distance between the guide roadside units 2, 3 and other local roadside units 62 to 6n, for example, by transmitting and receiving measurement signals between the guide roadside units 2, 3 and other local roadside units 62 to 6n via the data communication line 9, and outputs the measured distance between the guide roadside units 2, 3 and other local roadside units 62 to 6n to the road shape estimation unit 61d and the absolute position estimation unit 61f.

[0026] When the RF antenna 61g receives a road-to-vehicle signal transmitted from the in-vehicle device 8, the RF signal transmitting / receiving unit 61b outputs the received road-to-vehicle signal to the RF signal analyzing unit 61c. Furthermore, when positioning support information is input from the positioning support information generating unit 61e as will be described later, the RF signal transmitting / receiving unit 61b transmits a road-to-vehicle signal including the input positioning support information from the RF antenna 61g to the in-vehicle device 8.

[0027] When the RF signal analysis unit 61c receives the road-to-vehicle signal from the RF signal transmission / reception unit 61b, it analyzes the received road-to-vehicle signal and outputs the analysis result of the road-to-vehicle signal to the road shape estimation unit 61d.

[0028] When the distance between the guide roadside unit 2, 3 and the other local roadside units 62 to 6 n is input from the distance measurement unit 61 a and the analysis result of the road-to-vehicle signal is input from the RF signal analysis unit 61 c, the road shape estimation unit 61 d estimates the road shape based on the input distance between the guide roadside unit 2, 3 and the other local roadside units 62 to 6 n and the analysis result of the road-to-vehicle signal, and outputs the estimated road shape to the positioning support information generation unit 61 e and the absolute position estimation unit 61 f. The road shape estimation unit 61 d estimates the curvature as the road shape from the difference in distance between the own device 61 and the guide roadside units 2, 3 and the distance between the local roadside unit 71 and the guide roadside units 4, 5 that are opposite to the own device 61 across the lane.

[0029] When the road shape is input from the road shape estimation unit 61d, the positioning support information generation unit 61e generates positioning support information and outputs the generated positioning support information to the RF signal transmission / reception unit 61b. The positioning support information includes a roadside device ID for identifying the own device 61, the distance between the own device 61 and the roadside device 71 facing across the lane, the absolute position of the own device 61, the relative position between the own device 61 and the guide roadside devices 2 and 3 and other local roadside devices 62 to 6n that the vehicle A has passed through, the number of lanes, the lane width of each lane, diagnostic information, a synchronization signal, etc. The diagnostic information is information including, for example, the error history of the own device 61. The relative position between the own device 61 and the guide roadside devices 2 and 3 and other local roadside devices 62 to 6n that the vehicle A has passed through is necessary when the onboard device 8 specifies the position of the roadside device 61, but is not necessary when the roadside device 61 specifies the position of the roadside device 61.

[0030] When the distance between the guide roadside units 2, 3 and other local roadside units 62 to 6n is input from the distance measurement unit 61a and the curvature as the road shape is input from the road shape estimation unit 61d, the absolute position estimation unit 61f estimates the absolute position based on the input curvature, the distance between the own unit 61 and the local roadside unit 71, the absolute positions of the guide roadside units 2, 3 and the absolute positions of the guide roadside units 4, 5.

[0031] The above has been described for the local road-side device 61, but the same applies to the other local road-side devices 62 to 6 n and 71 to 7 n. Below, a case where the local road-side device 62 autonomously determines its absolute position will be described, taking the local road-side device 62 as a representative. As shown in FIG. 5 , the local road-side device 62 estimates its absolute position based on the curvature estimated from the difference between the distance L1 between itself and the guide road-side device 2 and the distance L2 between the local road-side device 72 and the guide road-side device 4, the distance L3 between itself and the local road-side device 72, the absolute position of the guide road-side device 2, and the absolute position of the guide road-side device 4. The local road-side device 62 may estimate its absolute position using the guide road-side devices 3 and 5 instead of the guide road-side devices 2 and 4. That is, the local road-side device 62 may estimate its own absolute position based on the curvature estimated from the difference between the distance between itself and the guide road-side device 3 and the distance between the local road-side device 72 and the guide road-side device 5, the distance L3 between itself and the local road-side device 72, the absolute position of the guide road-side device 3, and the absolute position of the guide road-side device 5. Furthermore, the local road-side device 6 may compare the absolute position estimated using the guide road-side devices 2 and 4 with the absolute position estimated using the guide road-side devices 3 and 5, and use the intermediate position as the absolute position.

[0032] The vehicle-mounted device 8 will now be described. As shown in FIG. 6 , the vehicle-mounted device 8 includes an RF signal receiving unit 8a (corresponding to a signal receiving unit), a pseudo-distance calculation unit 8b, a roadside device position estimating unit 8c, a road shape estimating unit 8d, and a positioning unit 8e. Each of these units 8a to 8e is configured by a microcomputer having a CPU, ROM, RAM, I / O, etc., and is realized by software control in which the CPU executes a computer program stored in a non-transient tangible storage medium, or hardware control in which a dedicated electronic circuit executes the program. The RF signal receiving unit 8a, the pseudo-distance calculation unit 8b, the roadside device position estimating unit 8c, the road shape estimating unit 8d, and the positioning unit 8e execute a vehicle position identification program. As shown in FIG. 7 , when vehicle A travels next to a local roadside device 62, the local roadside device 62 corresponds to the first roadside device, and the local roadside device 72 corresponds to the second roadside device.

[0033] When the RF signal receiver 8a receives a road-to-vehicle signal transmitted from a roadside unit via the RF antenna 8f, it analyzes the received road-to-vehicle signal and outputs the analysis results to the pseudo distance calculator 8b and the road shape estimator 8d. The RF signal receiver 8a outputs candidates for the pseudo distance between vehicle A and the roadside unit that transmitted the road-to-vehicle signal, and the roadside unit ID of the roadside unit that transmitted the road-to-vehicle signal, to the pseudo distance calculator 8b. The RF signal receiver 8a outputs the number of lanes and the width of each lane to the road shape estimator 8d.

[0034] When the pseudo distance calculation unit 8b receives the pseudo distance candidates and roadside unit ID from the RF signal receiving unit 8a, it calculates the pseudo distance between vehicle A and the roadside unit that sent the road-to-vehicle signal, assuming that the pseudo distance candidates have been input from two opposing roadside units, and outputs the calculated pseudo distance to the roadside unit position estimation unit 8c and the positioning unit 8e.

[0035] When the pseudo distance between vehicle A and the roadside device that is the source of the road-to-vehicle signal is input from the pseudo distance calculation unit 8b, the roadside device position estimating unit 8c estimates the position of the roadside device based on the input pseudo distance and outputs the estimated position of the roadside device to the road shape estimating unit 8d and the positioning unit 8e. The roadside device position estimating unit 8c may transmit the estimated position of the roadside device to the guiding roadside device when vehicle A passes through the tunnel exit.

[0036] When the number of lanes and the lane width of each lane are input from the RF signal receiving unit 8a and the position of the roadside unit is input from the roadside unit position estimating unit 8c, the road shape estimating unit 8d estimates the road shape based on the input position of the roadside unit, the number of lanes, and the lane width of each lane, and outputs the estimated road shape to the positioning unit 8e.

[0037] When the positioning unit 8e receives the pseudo distance between vehicle A and the roadside unit that is the source of the road-to-vehicle signal from the pseudo distance calculation unit 8b, the position of the roadside unit from the roadside unit position estimating unit 8c, and the road shape from the road shape estimating unit 8d, it locates the vehicle's position based on the input pseudo distance, the position of the roadside unit, and the road shape. The positioning unit 8e restricts the pseudo distance based on the pseudo distance, the position of the roadside unit, and the road shape, and then locates the vehicle's position based on the pseudo distance and the road shape.

[0038] A case in which the on-board device 8 determines its own vehicle position will be described. As shown in Fig. 7 , a case in which vehicle A enters a short-range communication area of ​​a local roadside device 62 will be described. In this case, the on-board device 8 receives a road-to-vehicle signal transmitted from the local roadside device 62 to calculate a pseudo distance P1 (corresponding to a first pseudo distance) between the on-board device 8 and the local roadside device 62, and receives a road-to-vehicle signal transmitted from a local roadside device 72 that faces the local roadside device 62 across the lane to calculate a pseudo distance P2 (corresponding to a second pseudo distance) between the on-board device 8 and the local roadside device 72. The on-board device 8 imposes constraints on at least one of the pseudo distances P1 and P2 based on the calculated pseudo distances P1 and P2, the estimated positions of the local roadside devices 62 and 72, and the estimated road shape. Imposing a constraint includes, for example, when it is assumed that at least one of the pseudo distances P1 and P2 is an inappropriate value, correcting the inappropriate value to an appropriate value when determining the vehicle position, or not adopting the inappropriate value.

[0039] The vehicle-mounted device 8 imposes a constraint on at least one of the pseudo distances P1 and P2 in the following cases: for example, the sum of the calculated pseudo distances P1 and P2 is greater than a value estimated from the road width and the arrival angle of the radio waves; the angular difference between the arrival direction of the road-to-vehicle signal from the local roadside device 62 and the arrival direction of the road-to-vehicle signal from the local roadside device 72 exceeds a predetermined angle; the pseudo distance P1 is longer than the pseudo distance P2; the fluctuation range per unit time of at least one of the pseudo distances P1 and P2 exceeds a predetermined value; etc. After imposing a constraint on at least one of the pseudo distances P1 and P2, the vehicle-mounted device 8 locates its own vehicle position based on the pseudo distances P1, P2 and the road shape.

[0040] Furthermore, the in-vehicle device 8 can also suppress signal spoofing by determining whether the road-to-vehicle signal transmitted from the local roadside device 62, 72 is a legitimate signal based on road information obtained from the analysis result of the road-to-vehicle signal, position information of the local roadside devices 62, 72, and the traveling trajectory calculated by the in-vehicle device 8. The in-vehicle device 8 may correct the traveling trajectory information when it determines that the road-to-vehicle signal transmitted from the local roadside device 62, 72 is a legitimate signal.

[0041] Next, the operation of the above-described configuration will be described with reference to Figures 8 to 22. The processing of the guide roadside unit, the processing of the local roadside unit, and the processing of the in-vehicle unit will be described. Note that in the following explanation, the guide roadside unit 2 and the local roadside unit 61 will be described as representatives, but the other guide roadside units 3 to 5 and the other local roadside units 62 to 6n and 71 to 7n also perform similar processing.

[0042] (1) Processing of the guide roadside unit (see Figs. 8 to 14) The guide roadside unit 2 can be both a guide roadside unit on the entrance side, which is the side entering the tunnel as seen from the vehicle, and a guide roadside unit on the exit side, which is the side exiting the tunnel, and therefore performs entrance-side steady-state processing and exit-side steady-state processing. The entrance-side steady-state processing and exit-side steady-state processing will be described.

[0043] (1-1) Entrance-side steady-state processing (see FIGS. 8 to 10) The guide road-side unit 2 performs vehicle detection processing, first periodic processing, and second periodic processing as entrance-side steady-state processing. When the guide road-side unit 2 detects that a vehicle has entered the short-range communication area that the guide road-side unit 2 has formed, it starts the vehicle detection processing. When the guide road-side unit 2 starts the vehicle detection processing, it photographs vehicle A that has detected that it has entered the short-range communication area (A1), transmits a road-to-vehicle signal including imaging information including the photographed image to the in-vehicle unit 8 (A2), and ends the vehicle detection processing.

[0044] The guide roadside unit 2 starts the first periodic process when it detects the start timing of the preset first periodic process. When the guide roadside unit 2 starts the first periodic process, it transmits a road-to-vehicle signal including health information indicating the status of the local roadside unit to the in-vehicle unit 8 (A11), and ends the first periodic process.

[0045] When the guide roadside unit 2 detects the start timing of the preset second periodic processing, the guide roadside unit 2 starts the second periodic processing. When the guide roadside unit 2 starts the second periodic processing, the guide roadside unit 2 transmits a time synchronization signal to the local roadside unit (A21) and ends the second periodic processing.

[0046] (1-2) Exit-side steady-state processing (see FIGS. 11 to 14) The guide road-side unit 2 performs vehicle detection processing, first periodic processing, second periodic processing, and diagnostic information analysis processing as exit-side steady-state processing. When the guide road-side unit 2 detects a vehicle entering the short-range communication area formed by the guide road-side unit 2, it starts the vehicle detection processing. When the guide road-side unit 2 starts the vehicle detection processing, it photographs vehicle A that has detected the vehicle entering the short-range communication area (A31), transmits a road-to-vehicle signal including imaging information including the photographed image to the in-vehicle unit 8 (A32), and ends the vehicle detection processing.

[0047] The guide roadside unit 2 starts the first periodic process when it detects the start timing of the preset first periodic process. When the guide roadside unit 2 starts the first periodic process, it transmits a road-to-vehicle signal including health information indicating the status of the local roadside unit to the in-vehicle unit 8 (A41), and ends the first periodic process.

[0048] When the guide roadside unit 2 detects the start timing of the preset second periodic processing, the guide roadside unit 2 starts the second periodic processing. When the guide roadside unit 2 starts the second periodic processing, the guide roadside unit 2 transmits a time synchronization signal to the local roadside unit (A51) and ends the second periodic processing.

[0049] The guiding roadside device 2 starts a diagnostic information analysis process when it detects receipt of diagnostic information transmitted from the vehicle-mounted device 8. When the guiding roadside device 2 starts the diagnostic information analysis process, it analyzes the received diagnostic information (A61) and ends the diagnostic information analysis process.

[0050] (2) Processing of Local Roadside Device (See FIGS. 15 and 16) The local roadside device 61 performs initialization processing before establishing the positioning support system and regular processing after establishing the positioning support system. The initialization processing and regular processing will be described.

[0051] (2-1) Initialization process (see FIG. 15) When the local road-side device 61 detects the timing to start the initialization process, it starts the initialization process. When the guide road-side device 2 starts the initialization process, it synchronizes with the guide road-side device that identifies the GNSS time (B1), estimates the absolute position of its own device by performing the procedure for estimating the absolute position of its own device described above (B2, corresponding to the absolute position estimation procedure), and ends the initialization process.

[0052] (2-2) Steady-state processing (see FIG. 16) When the local road-side device 61 detects time synchronization with the guide road-side device or another local road-side device, it starts steady-state processing. When the local road-side device 61 starts steady-state processing, it transmits a road-to-vehicle signal including the positioning assistance information described above to the in-vehicle device 8 (B11), and then ends steady-state processing. That is, the road-to-vehicle signal transmitted from the local road-side device 61 to the in-vehicle device 8 includes a road-side device ID for identifying the local road-side device 61, the distance between the local road-side device 61 and the oncoming road-side device 71, the absolute position of the local road-side device 61 estimated according to the procedure described above, the relative positions of the local road-side device 61 and the guide road-side device or other local road-side devices that vehicle A has passed, the number of lanes, the lane width of each lane, diagnostic information, a synchronization signal, etc.

[0053] (3) Processing of the on-board device (see Figs. 17 to 22) The on-board device 8 performs tunnel entry processing when vehicle A enters a tunnel, steady-state processing when vehicle A is traveling in the tunnel, and tunnel exit processing when vehicle A exits the tunnel. The tunnel entry processing, steady-state processing, and tunnel exit processing will be described in order.

[0054] (3-1) Processing when entering a tunnel (see FIGS. 17 and 18) The vehicle-mounted device 8 performs positioning processing and health information analysis processing as processing when entering a tunnel. The vehicle-mounted device 8 starts positioning processing when it detects the reception of a road-to-vehicle signal including imaging information transmitted from a guiding roadside device. When starting the positioning processing, the vehicle-mounted device 8 analyzes the received road-to-vehicle signal (C1), analyzes the imaging information included in the road-to-vehicle signal (C2), performs positioning based on the analysis results of the imaging information (C3), and ends the positioning processing.

[0055] When the vehicle-mounted device 8 detects the reception of a road-to-vehicle signal including health information transmitted from a guiding roadside device, the vehicle-mounted device 8 starts a health information analysis process. When the vehicle-mounted device 8 starts the health information analysis process, it analyzes the received road-to-vehicle signal (C11), analyzes the health information included in the road-to-vehicle signal (C12), and ends the health information analysis process.

[0056] (3-2) Steady-state Processing (FIG. 19) When the onboard device 8 detects the reception of a road-to-vehicle signal including positioning assistance information transmitted from a local roadside device (corresponding to the signal reception procedure), the onboard device 8 starts steady-state processing. Upon starting steady-state processing, the onboard device 8 performs the procedure for identifying the vehicle's own position described above, thereby analyzing the received road-to-vehicle signal (C21), calculating a pseudo-range based on the positioning assistance information included in the road-to-vehicle signal (C22, corresponding to the pseudo-range calculation procedure), estimating the position of the local roadside device (C23, corresponding to the roadside device position estimation procedure), and estimating the road shape (C24, corresponding to the road shape estimation procedure). The onboard device 8 imposes constraints on the pseudo-range based on the calculated pseudo-range, the estimated position of the local roadside device, and the estimated road shape, and performs positioning to identify the vehicle's own position based on the pseudo-range and the road shape (C25, corresponding to the vehicle position identification procedure), and then ends steady-state processing.

[0057] (3-3) Tunnel Exit Processing (See Figures 20 to 22) The vehicle-mounted device 8 performs a positioning process, a health information analysis process, and a diagnostic information transmission process as a tunnel exit processing. When the vehicle-mounted device 8 detects the reception of a road-to-vehicle signal including imaging information transmitted from a guiding roadside device, the vehicle-mounted device 8 starts the positioning process. When the positioning process starts, the vehicle-mounted device 8 analyzes the received road-to-vehicle signal (C31), analyzes the imaging information included in the road-to-vehicle signal (C32), performs positioning based on the analysis results of the imaging information (C33), and ends the positioning process.

[0058] When the vehicle-mounted device 8 detects the reception of a road-to-vehicle signal including health information transmitted from a guiding roadside device, the vehicle-mounted device 8 starts a health information analysis process. When the vehicle-mounted device 8 starts the health information analysis process, it analyzes the received road-to-vehicle signal (C41), analyzes the health information included in the road-to-vehicle signal (C42), and ends the health information analysis process.

[0059] When the vehicle-mounted device 8 detects that diagnostic information to be transmitted to the guiding roadside device has been accumulated, the vehicle-mounted device 8 starts the diagnostic information transmission process. When the vehicle-mounted device 8 starts the diagnostic information transmission process, the vehicle-mounted device 8 transmits a road-to-vehicle signal including the diagnostic information to the guiding roadside device (C51), and ends the diagnostic information transmission process.

[0060] As described above, this embodiment can achieve the following advantageous effects. For example, when vehicle A travels beside the local roadside device 62, the onboard device 8 calculates the pseudo distance P1 between the onboard device 8 and the local roadside device 62 and the second pseudo distance P2 between the onboard device 8 and the local roadside device 72, and then specifies the vehicle's position based on the pseudo distances P1, P2 and the road shape after restricting at least one of the calculated pseudo distances P1, P2. By restricting at least one of the pseudo distances P1, P2, it is possible to avoid a decrease in the accuracy of the pseudo distances P1, P2 due to the influence of radio wave propagation, and it is possible to appropriately improve positioning accuracy by avoiding the influence of radio wave propagation.

[0061] The local roadside devices 61 to 6 n and 71 to 7 n are configured to estimate their own absolute positions. By having the local roadside devices 61 to 6 n and 71 to 7 n autonomously estimate their absolute positions, it is possible to eliminate the need for accurate maps or accurate installation of the roadside devices, and by transmitting the estimated absolute positions to the in-vehicle device, the roadside devices can autonomously perform appropriate positioning assistance.

[0062] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0063] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0064] In addition to the claims, the present disclosure also includes the following disclosure. [1] A positioning system (1) comprising a roadside device (61) installed in a tunnel and an on-board device (8) mounted on a vehicle traveling in the tunnel, and performing road-to-vehicle communication between the roadside device and the on-board device, wherein the on-board device comprises: a signal receiving unit (8a) that receives road-to-vehicle signals transmitted from a first roadside device and a second roadside device that face each other across a lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the on-board device and the first roadside device and a second pseudo-distance between the on-board device and the second roadside device based on pseudo-distance candidates included in the road-to-vehicle signal; a roadside device position estimating unit (8c) that estimates the position of the first roadside device based on the first pseudo-distance calculated by the pseudo-distance calculation unit and that estimates the position of the second roadside device based on the second pseudo-distance; and a road shape estimating unit (8d) that estimates a road shape based on the positions of the first roadside device and the second roadside device. a positioning unit (8e) that specifies the vehicle position based on the first pseudo distance, the second pseudo distance, and the road shape, after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

[0065] [2] The positioning system according to [1], wherein the positioning unit imposes a constraint on at least one of the first pseudorange and the second pseudorange when the sum of the first pseudorange and the second pseudorange is greater than a value estimated from the road width and the angle of arrival of the road-to-vehicle signal.

[0066] [3] The positioning system according to [1] or [2], wherein the positioning unit imposes a constraint on at least one of the first pseudorange and the second pseudorange when an angular difference between the direction of arrival of the road-to-vehicle signal transmitted from the first roadside device and the direction of arrival of the road-to-vehicle signal transmitted from the second roadside device exceeds a predetermined angle.

[0067] [4] The positioning system according to any one of [1] to [3], wherein the positioning unit imposes a constraint on at least one of the first pseudo distance and the second pseudo distance when the first pseudo distance is longer than the second pseudo distance while the vehicle is traveling in the lane on the side of the first roadside device.

[0068] [5] The positioning system according to any one of [1] to [4], wherein the positioning unit imposes a constraint on at least one of the first pseudorange and the second pseudorange when a fluctuation range per unit time of at least one of the first pseudorange and the second pseudorange exceeds a predetermined value.

Claims

1. A positioning system (1) comprising a roadside unit (61) installed in a tunnel and an onboard unit (8) mounted on a vehicle traveling in the tunnel, for performing road-to-vehicle communication between the roadside unit and the onboard unit, wherein the onboard unit comprises: a signal receiving unit (8a) for receiving road-to-vehicle signals transmitted from a first roadside unit and a second roadside unit that face each other across a lane; a pseudo-distance calculation unit (8b) for calculating a first pseudo-distance between the onboard unit and the first roadside unit and a second pseudo-distance between the onboard unit and the second roadside unit based on pseudo-distance candidates included in the road-to-vehicle signal; a roadside unit position estimating unit (8c) for estimating the position of the first roadside unit based on the first pseudo-distance calculated by the pseudo-distance calculation unit and estimating the position of the second roadside unit based on the second pseudo-distance; and a road shape estimating unit (8d) for estimating road shapes based on the positions of the first roadside unit and the second roadside unit. a positioning unit (8e) that specifies the vehicle position based on the first pseudo distance, the second pseudo distance, and the road shape, after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

2. A positioning system as described in claim 1, wherein the positioning unit imposes a constraint on at least one of the first pseudorange and the second pseudorange when the sum of the first pseudorange and the second pseudorange is greater than a value estimated from the road width and the angle of arrival of the road-to-vehicle signal.

3. A positioning system as described in claim 1, wherein the positioning unit imposes a restriction on at least one of the first pseudorange and the second pseudorange when the angular difference between the direction of arrival of the road-to-vehicle signal transmitted from the first roadside device and the direction of arrival of the road-to-vehicle signal transmitted from the second roadside device exceeds a predetermined angle.

4. A positioning system as described in claim 1, wherein the positioning unit imposes a constraint on at least one of the first pseudo distance and the second pseudo distance when the first pseudo distance is longer than the second pseudo distance while the vehicle is traveling in the lane on the side of the first roadside device.

5. A positioning system as described in claim 1, wherein the positioning unit imposes a restriction on at least one of the first pseudorange and the second pseudorange when the fluctuation range per unit time of at least one of the first pseudorange and the second pseudorange exceeds a predetermined value.

6. An on-board device (8) mounted on a vehicle traveling in a tunnel and performing road-to-vehicle communication with a roadside device (61) installed in the tunnel, comprising: a signal receiving unit (8a) that receives road-to-vehicle signals transmitted from a first roadside device and a second roadside device that face each other across a lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the on-board device and the first roadside device and a second pseudo-distance between the on-board device and the second roadside device based on pseudo-distance candidates included in the road-to-vehicle signal; a roadside device position estimation unit (8c) that estimates the position of the first roadside device based on the first pseudo-distance calculated by the pseudo-distance calculation unit and estimates the position of the second roadside device based on the second pseudo-distance; and a road shape estimation unit (8d) that estimates road shapes based on the positions of the first roadside device and the second roadside device. and a positioning unit (8e) that specifies the vehicle position based on the first pseudo distance, the second pseudo distance, and the road shape, after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

7. An on-board device (8) mounted on a vehicle traveling in a tunnel and performing road-to-vehicle communication with a roadside device (61) installed in the tunnel, comprising: a signal reception procedure for receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device facing each other across a lane; a pseudo-distance calculation procedure for calculating a first pseudo-distance between the on-board device and the first roadside device and a second pseudo-distance between the on-board device and the second roadside device based on pseudo-distance candidates included in the road-to-vehicle signals; a roadside device position estimation procedure for estimating the position of the first roadside device based on the first pseudo-distance calculated by the pseudo-distance calculation procedure and estimating the position of the second roadside device based on the second pseudo-distance; and a road shape estimation procedure for estimating road shapes based on the positions of the first roadside device and the second roadside device. and a vehicle position determination program that executes a positioning procedure that determines the vehicle position based on the first pseudo distance, the second pseudo distance, and the road shape, after restricting at least one of the first pseudo distance and the second pseudo distance based on the first pseudo distance, the second pseudo distance, the position of the first roadside device, the position of the second roadside device, and the road shape.

8. A positioning system (1) comprising a roadside unit (61) installed inside a tunnel and an on-board unit (8) mounted on a vehicle traveling inside the tunnel, for performing road-to-vehicle communication between the roadside unit and the on-board unit, wherein the roadside unit comprises: a curvature estimated from the difference in distance between the roadside unit and a first guide roadside unit (2, 3) arranged parallel to the roadside unit, and the distance between an oncoming roadside unit (71) facing the roadside unit across a lane and a second guide roadside unit (4, 5) facing the first guide roadside unit across a lane, the distance between the roadside unit and the oncoming roadside unit, the absolute position of the first guide roadside unit, and the absolute position of the second guide roadside unit.

9. A roadside device (61) that is installed in a tunnel and performs road-to-vehicle communication with an onboard device (8) mounted on a vehicle traveling in the tunnel, the roadside device comprising: an absolute position estimation unit (61f) that estimates an absolute position based on the curvature estimated from the difference in distance between itself and a first guide roadside device (2, 3) that is parallel to itself, and the distance between an oncoming roadside device (71) that faces itself across a lane and a second guide roadside device (4, 5) that faces the first guide roadside device across a lane, the distance between itself and the oncoming roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

10. An absolute position estimation program that causes a roadside device (61) that is installed in a tunnel and performs road-to-vehicle communication with an onboard device (8) mounted on a vehicle traveling in the tunnel to execute an absolute position estimation procedure that estimates an absolute position based on the curvature estimated from the difference in distance between the roadside device (61) and a first guide roadside device (2, 3) that is parallel to the roadside device itself, and the distance between an oncoming roadside device (71) that faces the roadside device across a lane and a second guide roadside device (4, 5) that faces the first guide roadside device across a lane, the distance between the roadside device itself and the oncoming roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

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