Positioning system, on-vehicle unit, own vehicle position specifying program, roadside unit, and absolute position estimation program

Abstract

To enhance positioning accuracy by avoiding the effects of radio wave propagation.SOLUTION: An on-vehicle unit 8 includes: a signal receiving unit 8a that receives road-to-vehicle communication signals transmitted from each of a first roadside unit and a second roadside unit opposed to each other across a lane; a pseudo distance calculation unit 8b that calculates a first pseudo distance between the on-vehicle unit and the first roadside unit and a second pseudo distance between the on-vehicle unit and the second roadside unit on the basis of candidate pseudo distances included in the road-to-vehicle communication signals; a roadside unit position estimation unit 8c that estimates a position of the first roadside unit on the basis of the first pseudo distance and estimates a position of the second roadside unit on the basis of the second pseudo distance; a road shape estimation unit 8d that estimates a road shape on the basis of the position of the first roadside unit and the position of the second roadside unit; and a positioning unit 8e that specifies an own vehicle position on the basis of the first pseudo distance, the second pseudo distance, and the road shape, after applying constraints to at least one of the first pseudo distance and the second pseudo distance using the position of the first roadside unit, the position of the second roadside unit, and the road shape.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a positioning system, an in-vehicle device, a vehicle position specifying program, a roadside device, and an absolute position estimation program. [Background technology]

[0002] In positioning using GNSS (Global Navigation Satellite System) satellites, a problem arises when performing positioning in a space where GNSS signals transmitted from GNSS satellites cannot be received, such as inside 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 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 or more significant measured values ​​from the GPS positioning device, the vehicle speed detection device, and the lateral ranging device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-211493 Summary of the Invention [Problem to be solved by the invention]

[0004] 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 effects of radio wave propagation. Another problem is that it is necessary to prepare accurate maps and install roadside units accurately.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and its first object is to provide a positioning system, an on-board device, and a vehicle position identification program that can appropriately improve positioning accuracy by avoiding the influence of radio wave propagation. A second object is to provide a positioning system, a roadside device, and an absolute position estimation program that enable a roadside device to appropriately perform positioning assistance autonomously. [Means for solving the problem]

[0006] According to a positioning system (1) described in claim 1, the system includes a roadside device (61) installed in a tunnel and an on-board device (8) mounted on a vehicle traveling in the tunnel, and performs road-to-vehicle communication between the roadside device and the on-board device. The on-board device includes 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 calculating 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 candidates of pseudo-distances included in the road-to-vehicle signals, and a pseudo-distance calculating unit (8b) that estimates the position of the first roadside device based on the first pseudo-distance calculated by the pseudo-distance calculating unit and calculates the position of the second roadside device based on the second pseudo-distance. a road shape estimation unit (8d) that estimates a road shape based on the position of the first roadside unit and the position of the second roadside unit; 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 unit, the position of the second roadside unit, and the road shape.

[0007] According to the in-vehicle device described in claim 6, the in-vehicle device is mounted on a vehicle traveling in a tunnel and performs road-to-vehicle communication with a road-side device (61) installed in the tunnel. The in-vehicle device includes a signal receiving unit (8a) that receives road-to-vehicle signals transmitted from a first road-side device and a second road-side device that face each other across a lane, a pseudo-distance calculating unit (8b) that calculates a first pseudo-distance between the vehicle and the first road-side device and a second pseudo-distance between the vehicle and the second road-side device based on candidates of pseudo-distances included in the road-to-vehicle signals, and a pseudo-distance calculating unit (8b) that estimates the position of the first road-side device based on the first pseudo-distance calculated by the pseudo-distance calculating unit and estimates the position of the second road-side device based on the second pseudo-distance. The vehicle position estimation unit (8c) includes a roadside device position estimation unit (8c), 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.

[0008] According to the vehicle position identification program of claim 7, 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 (8) that is mounted on a vehicle traveling in a tunnel and performs road-to-vehicle communication with a roadside device (61) 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. a roadside device position estimation procedure for estimating the position of the first roadside device based on the second pseudo distance and estimating the position of a second roadside device based on the second pseudo distance; a road shape estimation procedure for estimating the road shape based on the positions of the first roadside device and the second roadside device; and a positioning procedure for specifying 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.

[0009] According to the disclosures of claims 1, 6, and 7, a first pseudo-range between the 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 restriction 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 restriction on at least one of the first pseudo-range and the second pseudo-range, it is possible to avoid a decrease in the 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.

[0010] According to a positioning system (1) described in claim 8, the system includes a roadside device (61) installed in a tunnel and an on-board device (8) mounted on a vehicle traveling in the tunnel, and road-to-vehicle communication is performed between the roadside device and the on-board device. The roadside device includes an absolute position estimation unit (61f) 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 (2, 3) arranged parallel to the roadside device, and a distance between an on-coming roadside device (71) facing the roadside device across a lane and a second guide roadside device (4, 5) facing the first guide roadside device across a lane, the distance between the roadside device and the on-coming roadside device, the absolute position of the first guide roadside device, and the absolute position of the second guide roadside device.

[0011] According to a ninth aspect of the present invention, the roadside device 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 includes an absolute position estimation unit (61f) that estimates an absolute position based on a curvature estimated from a difference between the distance between the own device and a first guide roadside device (2, 3) arranged in parallel with the own device and the distance between an oncoming roadside device (71) facing the own device across a lane and a second guide roadside device (4, 5) facing the first guide roadside device across a lane, the distance between the own 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 the absolute position estimation program recited in claim 10, 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 is made to execute an absolute position estimation procedure 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.

[0013] According to the disclosures of claims 8 to 10, the absolute position of the roadside unit is estimated. By having the roadside unit autonomously estimate the absolute position, it becomes unnecessary to prepare an accurate map or to install the roadside unit accurately, and by transmitting the estimated absolute position to the in-vehicle unit, the roadside unit can autonomously perform appropriate positioning assistance. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating an overall configuration of an embodiment; [Figure 2] Diagram showing the connection of roadside units [Figure 3] Diagram showing the connection of roadside units [Figure 4] Functional block diagram showing the configuration of a local roadside unit [Figure 5] Diagram explaining absolute position estimation [Figure 6] Functional block diagram showing the configuration of the in-vehicle device [Figure 7] FIG. 1 is a diagram illustrating calculation of pseudoranges. [Figure 8] Flowchart showing vehicle detection processing performed by the guide roadside device (entrance side) [Figure 9] Flowchart showing the first periodic process performed by the guide roadside unit (entrance side) [Figure 10] Flowchart showing the second periodic process performed by the guide roadside unit (entrance side) [Figure 11]Flowchart showing the vehicle detection process performed by the guide roadside device (exit side) [Figure 12] Flowchart showing the first periodic process performed by the guide roadside unit (exit side) [Figure 13] Flowchart showing the second periodic process performed by the guide roadside unit (exit side) [Figure 14] Flowchart showing diagnostic information analysis processing performed by the guide roadside unit (exit side) [Figure 15] Flowchart showing initialization processing performed by a local roadside unit [Figure 16] Flowchart showing the steady-state processing performed by the local roadside unit [Figure 17] Flowchart showing the positioning process performed by the onboard device when entering a tunnel [Figure 18] Flowchart showing the health information analysis process performed by the on-board device when entering a tunnel [Figure 19] Flowchart showing the steady-state processing performed by the onboard device when driving through a tunnel [Figure 20] Flowchart showing the positioning process performed by the onboard device when exiting a tunnel [Figure 21] Flowchart showing the health information analysis process performed by the on-board device when exiting a tunnel [Figure 22] A flowchart showing the diagnostic information transmission process performed by the vehicle-mounted device when exiting a tunnel. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment will be described with reference to the drawings. As shown in Fig. 1, a guide road-side unit 2, local road-side units 61-6n (corresponding to road-side units), and a guide road-side unit 3 are arranged in a row along the shape of one wall W1 that forms a tunnel, and a guide road-side unit 4, local road-side units 71-7n (corresponding to road-side units), and a guide road-side unit 5 are arranged in a row along the shape of the other wall W2. When vehicle A travels through a tunnel, guide road-side unit 2, local road-side units 61-6n, and guide road-side unit 3 are installed on the driving lane side of vehicle A, and guide road-side unit 4, local road-side units 71-7n, and guide road-side unit 5 are installed on the opposite lane side of vehicle A. The positioning system 1 is configured to include guide road-side units 2-5, local road-side units 61-6n, 71-7n, and an on-board unit 8 installed in vehicle A.

[0016] 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.

[0017] The guide roadside units 2 to 5 are all installed in positions where they can see 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 position and time synchronization for the local roadside units 61 to 6 n, 71 to 7 n.

[0018] Furthermore, the guide roadside units 2 to 5 are equipped with cameras that capture images of vehicles entering or exiting a tunnel, and transmit road-to-vehicle signals including captured image information to the in-vehicle unit 8. Furthermore, the guide roadside units 2 and 3 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.

[0019] 1, when vehicle A travels 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.

[0020] The local road-side units 61 to 6n are arranged in parallel between the guide road-side units 2 and 3. The local road-side units 71 to 7n are arranged in parallel between the guide road-side units 4 and 5. The local road-side units 61 to 6n and the local road-side units 71 to 7n are installed opposite each other across a lane. That is, the local road-side units 61 and 71 are installed opposite each other across a lane, and the local road-side units 6n and 7n are installed opposite each other across a lane. The local road-side units 61 to 6n and 71 to 7n are all installed in positions where they cannot see GNSS satellites, that is, where they cannot receive GNSS signals transmitted from 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.

[0021] As shown in FIG. 2, the guide road-side units 2, 3 and the local road-side units 61-6n are connected to each other so that data can be communicated via a data communication line 9 such as an optical fiber. The guide road-side units 2, 3 perform data communication with the local road-side units 61-6n via the data communication line 9, and determine whether or not the local road-side units 61-6n 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 road-side units 4, 5 and the local road-side units 71-7n are connected to each other so that data can be communicated via a data communication line 10 such as an optical fiber. The guide road-side units 4, 5 perform data communication with the local road-side units 71-7n via the data communication line 10, and determine whether or not the local road-side units 71-7n are operating normally, for example, by determining whether or not there is a response to the transmission of a test signal.

[0022] The local road-side devices 61 to 6n and 71 to 7n will be described below. Because the local road-side devices 61 to 6n and 71 to 7n have the same configuration, the local road-side device 61 will be described as a representative. When describing the local road-side device 61 as a representative, the local road-side device 71 corresponds to the opposing road-side device, the guide road-side devices 2 and 3 correspond to the first guide road-side device, and the guide road-side devices 4 and 5 correspond to the second guide road-side device.

[0023] 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 software processing control in which the CPU executes a computer program stored in a non-transitory physical storage medium, or hardware processing control by a dedicated electronic circuit. The absolute position estimation unit 61f executes an absolute position estimation program.

[0024] 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.

[0025] 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.

[0026] When the road-to-vehicle signal is input from the RF signal transmitting / receiving unit 61b, the RF signal analyzing unit 61c analyzes the input road-to-vehicle signal and outputs the analysis result of the road-to-vehicle signal to the road shape estimating unit 61d.

[0027] When the distance between the guide road-side unit 2, 3 and the other local road-side units 62-6n is input from the distance measurement unit 61a and the analysis result of the road-vehicle signal is input from the RF signal analysis unit 61c, the road shape estimation unit 61d estimates the road shape based on the input distance between the guide road-side unit 2, 3 and the other local road-side units 62-6n and the analysis result of the road-vehicle signal, and outputs the estimated road shape to the positioning support information generation unit 61e and the absolute position estimation unit 61f. The road shape estimation unit 61d estimates the curvature as the road shape from the difference in distance between the own device 61 and the guide road-side units 2, 3 and the distance between the local road-side unit 71 and the guide road-side units 4, 5, which are opposite to the own device 61 across the lane.

[0028] 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 in-vehicle 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.

[0029] 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.

[0030] 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 6n and 71 to 7n. 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 roadside device 62 may estimate its absolute position based on the curvature estimated from the difference between the distance between itself and the guide roadside device 3 and the distance between the local roadside device 72 and the guide roadside device 5, the distance L3 between itself and the local roadside device 72, the absolute position of the guide roadside device 3, and the absolute position of the guide roadside device 5. Furthermore, the local roadside device 62 may compare the absolute position estimated using the guide roadside devices 2 and 4 with the absolute position estimated using the guide roadside devices 3 and 5, and use the intermediate position as the absolute position.

[0031] 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 processing control in which the CPU executes a computer program stored in a non-transitory physical storage medium, or hardware processing control by a dedicated electronic circuit. A vehicle position identification program is executed by 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. As shown in FIG. 7, which will be described later, when vehicle A travels beside 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.

[0032] 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.

[0033] When the pseudo distance calculation unit 8b receives the pseudo distance candidates and the 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 received from two opposing roadside units, and outputs the calculated pseudo distance to the roadside unit position estimation unit 8c and the positioning unit 8e.

[0034] When the pseudo distance between vehicle A and the roadside unit that is the source of the road-to-vehicle signal is input from the pseudo distance calculation unit 8b, the roadside unit position estimation unit 8c estimates the position of the roadside unit based on the input pseudo distance and outputs the estimated position of the roadside unit to the road shape estimation unit 8d and the positioning unit 8e. The roadside unit position estimation unit 8c may transmit the estimated position of the roadside unit to the guiding roadside unit when vehicle A passes through the tunnel exit.

[0035] 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.

[0036] 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 estimation unit 8c, and the road shape from the road shape estimation unit 8d, it determines the vehicle position based on the input pseudo distance, the position of the roadside unit, and the road shape. The positioning unit 8e determines the vehicle position based on the pseudo distance and the road shape after restricting the pseudo distance based on the pseudo distance, the position of the roadside unit, and the road shape.

[0037] A case where the on-board device 8 identifies its own vehicle position will be described. As shown in Fig. 7, a case where 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 calculates a pseudo distance P1 (corresponding to a first pseudo distance) between the on-board device 8 and the local roadside device 62 by receiving a road-to-vehicle signal transmitted from the local roadside device 62, and calculates a pseudo distance P2 (corresponding to a second pseudo distance) between the on-board device 8 and the local roadside device 72 by receiving a road-to-vehicle signal transmitted from a local roadside device 72 that faces the local roadside device 62 across a lane. 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.

[0038] 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.

[0039] Furthermore, the vehicle-mounted device 8 can also prevent 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 vehicle-mounted device 8. The vehicle-mounted 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.

[0040] Next, the operation of the above-mentioned configuration will be described with reference to Fig. 8 to Fig. 22. Processing by the guide roadside device, processing by the local roadside device, and processing by the in-vehicle device will be described. Note that in the following description, the guide roadside device 2 and the local roadside device 61 will be described as representatives, but the other guide roadside devices 3 to 5 and other local roadside devices 62 to 6n, 71 to 7n also perform similar processing.

[0041] (1) Processing by the guide roadside unit (see Figures 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, so it 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 below.

[0042] (1-1) Inlet side steady-state processing (see Figures 8 to 10) The guide road-side unit 2 performs vehicle detection processing, first periodic processing, and second periodic processing as entrance-side steady processing. When the guide roadside device 2 detects that a vehicle has entered the short-range communication area that it has formed, it starts a vehicle detection process. When the guide roadside device 2 starts the vehicle detection process, it takes an image of vehicle A that has been detected entering the short-range communication area (A1), transmits a road-to-vehicle signal including imaging information including the captured image to the in-vehicle device 8 (A2), and ends the vehicle detection process.

[0043] 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.

[0044] When the guide roadside device 2 detects the start timing of the preset second periodic processing, it starts the second periodic processing. When the guide roadside device 2 starts the second periodic processing, it transmits a time synchronization signal to the local roadside device (A21) and ends the second periodic processing.

[0045] (1-2) Outlet-side steady-state processing (see Figures 11 to 14) The guide road-side unit 2 performs vehicle detection processing, first period processing, second period processing, and diagnostic information analysis processing as exit-side steady processing. When the guide roadside device 2 detects that a vehicle has entered the short-range communication area that it has formed, it starts the vehicle detection process. When the guide roadside device 2 starts the vehicle detection process, it takes an image of vehicle A that has been detected entering the short-range communication area (A31), transmits a road-to-vehicle signal including imaging information including the captured image to the in-vehicle device 8 (A32), and ends the vehicle detection process.

[0046] 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.

[0047] When the guide roadside device 2 detects the start timing of the preset second periodic processing, it starts the second periodic processing. When the guide roadside device 2 starts the second periodic processing, it transmits a time synchronization signal to the local roadside device (A51) and ends the second periodic processing.

[0048] The guiding roadside device 2 starts a diagnostic information analysis process when it detects receipt of the 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.

[0049] (2) Processing by local roadside units (see Figures 15 and 16) The local roadside device 61 performs initialization processing before the positioning support system is established and regular processing after the positioning support system is established. The initialization processing and regular processing will be described below.

[0050] (2-1) Initialization process (see Figure 15) When the local roadside device 61 detects the timing to start the initialization process, it starts the initialization process. When the guide roadside device 2 starts the initialization process, it synchronizes with the guide roadside device that identifies the GNSS time (B1), and estimates its absolute position by performing the procedure for estimating its own absolute position described above (B2, which corresponds to the absolute position estimation procedure), and then ends the initialization process.

[0051] (2-2) Steady-state processing (see Figure 16) When the local roadside device 61 detects time synchronization with the guide roadside device or other local roadside devices, it starts steady-state processing. When the local roadside 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 roadside device 61 to the in-vehicle device 8 includes a roadside device ID for identifying the local roadside device 61, the distance between the local roadside device 61 and the oncoming roadside device 71, the absolute position of the local roadside device 61 estimated according to the procedure described above, the relative positions of the local roadside device 61 and the guide roadside device or other local roadside devices that vehicle A has passed through, the number of lanes, the lane width of each lane, diagnostic information, a synchronization signal, etc.

[0052] (3) Processing of the onboard device (see Figures 17 to 22) The on-board device 8 performs a tunnel entry process when vehicle A enters a tunnel, a steady-state process when vehicle A is traveling in the tunnel, and a tunnel exit process when vehicle A exits the tunnel. The tunnel entry process, steady-state process, and tunnel exit process will be described in order.

[0053] (3-1) Processing when entering a tunnel (see Figures 17 and 18) The vehicle-mounted device 8 performs a positioning process and a health information analysis process as a process for 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 the 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 result of the imaging information (C3), and ends the positioning processing.

[0054] 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.

[0055] (3-2) Steady-state processing (Figure 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 a signal reception procedure), it starts steady-state processing. When the onboard device 8 starts steady-state processing, it performs the procedure for identifying its own vehicle 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 a pseudo-range calculation procedure), estimating the position of the local roadside device (C23, corresponding to a roadside device position estimation procedure), and estimating the road shape (C24, corresponding to a 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 its own vehicle position based on the pseudo-range and road shape (C25, corresponding to a vehicle position identification procedure), and then ends steady-state processing.

[0056] (3-3) Processing when exiting a tunnel (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 process for exiting 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 the guiding roadside device. When starting the positioning processing, 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 result of the imaging information (C33), and ends the positioning processing.

[0057] When the vehicle-mounted device 8 detects the reception of a road-to-vehicle signal including health information transmitted from a guiding roadside device, it 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.

[0058] 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.

[0059] As described above, according to this embodiment, the following advantageous effects can be obtained. 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.

[0060] The local roadside devices 61-6n and 71-7n are configured to estimate their own absolute positions. By having the local roadside devices 61-6n and 71-7n autonomously estimate their absolute positions, it becomes unnecessary to prepare accurate maps or to install the roadside devices accurately. By transmitting the estimated absolute positions to the in-vehicle device, the roadside devices can autonomously provide appropriate positioning assistance.

[0061] 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.

[0062] 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.

[0063] In addition to the claims, the present disclosure also includes the following inventions. [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, The vehicle-mounted device is a signal receiving unit (8a) for receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device that are opposite each other across a lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the host device and a first roadside device and a second pseudo-distance between the host device and a second roadside device based on the pseudo-distance candidates included in the road-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; a road shape estimation 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.

[0064] [2] The positioning system described in [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.

[0065] [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 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.

[0066] [4] A positioning system according to any one of claims [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 unit.

[0067] [5] The positioning system according to any one of claims [1] to [4], wherein the positioning unit imposes a constraint 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. [Explanation of symbols]

[0068] In the drawing, 1 is a positioning system, 2 to 5 are guide roadside units, 8 is an in-vehicle unit, 8a is an RF signal receiving unit, 8b is a pseudo-distance calculation unit, 8c is a roadside unit position estimation unit, 8d is a road shape estimation unit, 8e is a positioning unit, 61 to 6n, 71 to 7n are local roadside units (roadside units), and 61f is an absolute position estimation unit.

Claims

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, The vehicle-mounted device is a signal receiving unit (8a) for receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device that are opposite each other across a lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the host device and a first roadside device and a second pseudo-distance between the host device and a second roadside device based on the 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 calculating unit, and that estimates the position of the second roadside device based on the second pseudo distance; a road shape estimation 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.

2. 2. The positioning system according to 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. 2. The positioning system according to claim 1, wherein the positioning unit imposes a restriction 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.

4. 2. The positioning system according to 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 a lane on the side of the first roadside device.

5. 2. The positioning system according to claim 1, wherein the positioning unit imposes a restriction 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.

6. An on-board device (8) is mounted on a vehicle traveling in a tunnel and performs road-to-vehicle communication with a roadside device (61) installed in the tunnel, a signal receiving unit (8a) for receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device that are opposite each other across a lane; a pseudo-distance calculation unit (8b) that calculates a first pseudo-distance between the host device and a first roadside device and a second pseudo-distance between the host device and a second roadside device based on the 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 calculating unit, and that estimates the position of the second roadside device based on the second pseudo distance; a road shape estimation unit (8d) that estimates a road shape 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) is mounted on a vehicle traveling in a tunnel and performs road-to-vehicle communication with a roadside device (61) installed in the tunnel, a signal receiving step of receiving road-to-vehicle signals transmitted from a first roadside device and a second roadside device that are opposite each other across a lane; a pseudo-distance calculation step of calculating a first pseudo-distance between the host device and a first roadside device and a second pseudo-distance between the host device and a second roadside device based on pseudo-distance candidates included in the road-vehicle signal; a roadside device position estimation step of estimating a position of the first roadside device based on the first pseudo distance calculated in the pseudo distance calculation step, and estimating a position of a second roadside device based on the second pseudo distance; a road shape estimation step of estimating a road shape 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 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, The roadside unit A positioning system comprising an absolute position estimation unit (61f) that estimates an absolute position based on a curvature estimated from the difference in distance between the vehicle and a first guide roadside unit (2, 3) that is parallel to the vehicle, and the distance between an oncoming roadside unit (71) that faces the vehicle across a lane and a second guide roadside unit (4, 5) that faces the first guide roadside unit across a lane, the distance between the vehicle 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) is installed in a tunnel and performs road-to-vehicle communication with an on-board device (8) mounted on a vehicle traveling in the tunnel, The roadside device is provided with an absolute position estimation unit (61f) that estimates an absolute position based on a curvature estimated from a difference in distance between the vehicle itself and a first guide roadside device (2, 3) that is parallel to the vehicle itself, and a distance between an oncoming roadside device (71) that faces the vehicle 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 the vehicle 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. A roadside device (61) is installed in a tunnel and performs road-to-vehicle communication with an on-board device (8) mounted on a vehicle traveling in the tunnel. An absolute position estimation program that executes an absolute position estimation procedure to estimate an absolute position based on a curvature estimated from the difference in distance between the vehicle and a first guide roadside unit (2, 3) that is parallel to the vehicle, and the distance between an oncoming roadside unit (71) that faces the vehicle across a lane and a second guide roadside unit (4, 5) that faces the first guide roadside unit across a lane, the distance between the vehicle and the oncoming roadside unit, the absolute position of the first guide roadside unit, and the absolute position of the second guide roadside unit.

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