WIRELESS COMMUNICATION DEVICE AND WIRELESS POSITIONING SYSTEM

Abstract

Wireless communication device (3, 103, 203), comprising: a wireless communication means (13, 133, 213) for receiving data transmitted by direct wireless communication from at least one wireless transmitter (2, 102, 203), wherein the at least one wireless transmitter (2, 102, 203) transmits data wirelessly; a detection device (21(S50), 22, 141(S340), 142, 221(S1050), 222) for detecting a wireless reception state in the wireless communication device; a reference information storage means (23, 143, 223) for storing relation reference information that establishes two or more relations between (i) the wireless receive state in the wireless communication means for receiving data transmitted by the wireless transmitter, and (ii) location information regarding a location of the wireless transmitter; a distance measuring device (21(S60), 22, 141(S360), 142, 221(S1070), 222) for measuring relative distance information regarding a relative distance between the wireless transmitter and the wireless communication device; a first generating means (21(S70), 22, 141(S360), 142, 221(S1070), 222) for generating first relation information that specifies a relation between several of the wireless receive states that are detected by the detection means and several of the relative distance information that is measured by the distance measuring means; a relation determination tool (21(S80), 22, 141(S370), 142, 221(S1100), 222) for determining a relation between the location information and the relative distance information by comparing the relation reference information and the first relation information; and a position determination means (21(S90, S100), 22, 141(S380, S390), 142, 221(S1110), 222) for determining a present location of the wireless communication device on the basis of (a) the relation between the location information and the relative distance information determined by the relation determination means, and (b) a present wireless reception state in the wireless communication means, which is detected by the detection means.

Description

BACKGROUND[Technical Area]

[0001] The present invention relates to a wireless communication device and a wireless positioning system that perform positioning by wireless communication. [State of the art]

[0002] GPS (Global Navigation Satellite System for Positioning and Timing) is commonly known as a wide-area positioning information service. However, GPS suffers from the problem that positioning information services are not available inside buildings or behind doors. Furthermore, GPS, which relies on GPS satellite infrastructure, also suffers from the problem that infrastructure failures or service outages render the use of positioning information services unusable.

[0003] A wireless LAN (local area network) positioning method has sometimes been used, which enables positioning that does not rely on a GPS satellite but uses electrical measurement information from a widely deployed wireless LAN. However, in the wireless LAN positioning method, the positioning accuracy depends on the number of base stations that can receive signals and specify positions. Therefore, the wireless LAN positioning method suffers from the cost of setting up base stations, which is involved in deploying the method over a wide area.

[0004] To solve the above problems, an infrastructure has been established that enables the provision of wide-area positioning information services that do not rely on a GPS satellite (see, for example, JP 2008 - 104 029 A). In this infrastructure, the information for detecting wireless LAN stations used for communication is aggregated in the cloud for so-called cloud computing using computing resources provided as a service over a network. The LAN stations can then be used as base stations for positioning, thereby reducing the cost of constructing base stations. Thus, wide-area positioning information services that do not rely on a GPS satellite become available.

[0005] However, the method of aggregating the information for detecting wireless LAN base stations in the cloud as disclosed in JP 2008 - 104 029 A also suffers from the fact that the positioning accuracy depends greatly on the density of the registered base stations.

[0006] Reference is further made to US 2012 / 0 062 381 A1, D2 EP 2 385 389 A1 and US 2011 / 0 260 923 A1, which were identified as prior art. OVERVIEW OF THE INVENTION

[0007] The present invention provides a method that enables positioning without depending on the density of surrounding base stations.

[0008] According to a first aspect of the present disclosure, there is provided a wireless communication device including: wireless communication means for receiving data transmitted from at least one wireless transmitter through direct wireless communication, wherein the at least one wireless transmitter transmits data wirelessly; detection means for detecting a wireless reception state in the wireless communication means; reference information storage means for storing relational reference information defining two or more relations between (i) the wireless reception state in the wireless communication means for receiving data transmitted from the wireless transmitter and (ii) location information regarding a location of the wireless transmitter;a distance measuring means for measuring relative distance information regarding a relative distance between the wireless transmitter and the wireless communication device; a first generating means for generating first relation information (first relation measurement information) indicating a relationship between a plurality of the wireless reception states detected by the detecting means and a plurality of the relative distance information measured by the distance measuring means; a relation determining means for determining a relationship between the location information and the relative distance information by comparing the relation reference information and the first relation information;and a position determining means for determining a current location of the wireless communication device based on (a) the relation between the location information and the relative distance information determined by the relation determining means and (b) a current wireless reception state in the wireless communication means detected by the detecting means.

[0009] The wireless communication device configured in this way can perform direct wireless communication with a single radio transmitter in association with the relational reference information, determining the current location of the wireless communication device. Thus, positioning can be performed regardless of the density of radio transmitters present around the wireless communication device.

[0010] In the wireless communication device, the wireless transmitter may be provided to be fixed at a predetermined installation position. The location information in the relational reference information may be information indicating a position on a road surrounding the wireless transmitter. The relative distance information in the first relational information may be a travel distance of a vehicle equipped with the wireless communication device traveling on the road surrounding the wireless transmitter. The relative distance information in the first relational information may be a travel distance (movement distance) of a vehicle equipped with the wireless communication device traveling on the road surrounding the wireless transmitter.

[0011] When the wireless communication device configured in this manner travels on a road, the device can perform direct wireless communication with a radio transmitter using the relational reference information to thereby determine the location of the wireless communication device on the road. This is because the radio transmitter is provided to be mounted at a predetermined installation position. Consequently, the device can determine relational information (i.e., relational reference information) between a wireless reception state of the radio transmitter and the information indicating the position on the road located around the radio transmitter. It should be noted that "the current location in the wireless communication device" as used above corresponds to the "current location on the road in the wireless communication device."

[0012] In the wireless communication device, the wireless transmitter may be mounted in a first moving object moving on a road. The location information in the relational reference information is information indicating a relative distance between the first moving object and the wireless communication device. The relative distance information around the first relational reference information is information indicating an increase and decrease of a relative distance between the first moving object and the wireless communication device with respect to a relative reference distance, which is a relative distance between the first moving object and the wireless communication device at a predetermined time.

[0013] When the wireless communication device configured in this manner moves near the first moving object, the device can perform direct wireless communication with a radio transmitter (i.e., the radio transmitter installed in the first moving object) based on the relational reference information, thereby determining a relative distance between the first moving object and the wireless communication device. It should be noted that in this case, the "current location in the wireless communication device" is the "current location relative to the first moving object," and thus corresponds to the "relative distance between the first moving object and the wireless communication device."

[0014] According to a second aspect of the present disclosure, a wireless positioning system is provided, comprising: the at least one wireless transmitter described above; and the wireless communication device described above. The wireless positioning system configured in this manner includes the wireless communication device according to claim 1 and can thus achieve similar effects to the wireless communication device according to claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] They show: Fig. 1 is a diagram illustrating a configuration of a wireless positioning system according to a first embodiment of the present invention; Fig. 2 is a block diagram showing a configuration of a vehicle-mounted device in the wireless positioning system of Fig. 1 illustrated; Fig. 3 is a block diagram showing a configuration of a management server in the wireless positioning system of Fig. 1 illustrated; Fig. 4 is a flowchart illustrating position estimation processing according to the first embodiment; Fig. 5 a diagram illustrating a reference trajectory; Fig. 6 a diagram illustrating reference trajectories of input and output tracks; Fig. 7 is an explanatory diagram illustrating a position determination method using a reference track and a test track; Fig. 8 is a flowchart illustrating career update processing according to the first embodiment; Fig. 9 is a diagram illustrating a specific example of position estimation according to the first embodiment; Fig. 10 is a diagram illustrating a configuration of a wireless positioning system according to a second embodiment of the present invention; Fig. 11 is a block diagram showing a configuration of a reference station in the wireless positioning system of Fig. 10 illustrated; Fig. 12 is a block diagram showing a configuration of a vehicle-mounted device 103 in the wireless positioning system of Fig. 10 illustrated; Fig. 13 is a flowchart illustrating position estimation processing according to the second embodiment; Fig. 14 is a flowchart illustrating career update processing according to the second embodiment; Fig. 15 is a diagram illustrating a specific example of position estimation according to the second embodiment; Fig. 16 is a diagram illustrating a specific example of position estimation according to a third embodiment of the present invention; Fig. 17 is a flowchart illustrating position estimation processing according to the third embodiment; Fig. 18 is a flowchart illustrating career update processing according to the third embodiment; Fig. 19 is a flowchart illustrating position estimation processing according to a fourth embodiment of the present invention; Fig. 20 is a flowchart illustrating career update processing according to the fourth embodiment; Fig. 21 is a diagram illustrating a specific example of position estimation according to the fourth embodiment; Fig. 22 is a diagram illustrating a configuration of a wireless positioning system according to a fifth embodiment of the present invention; Fig. 23 is a block diagram showing a configuration of a vehicle-mounted device in the wireless positioning system of Fig. 22 illustrated; Fig. 24 is a block diagram showing a configuration of a management server in the wireless positioning system of Fig. 22 illustrated; Fig. 25 is a flowchart illustrating position estimation processing according to the fifth embodiment; Fig. 26 is a diagram illustrating an inter-vehicle distance reference trajectory; Fig. 27 is a diagram illustrating an inter-vehicle distance test trajectory; Fig. 28 is a flowchart illustrating career update processing according to the fifth embodiment; Fig. 29 is a diagram illustrating a specific example of inter-vehicle distance estimation according to the fifth embodiment; Fig. 30 is a flowchart illustrating position estimation processing according to a sixth embodiment of the present invention; Fig. 31 is a diagram illustrating a specific example of inter-vehicle distance estimation according to the sixth embodiment; Fig. 32 is a diagram illustrating a specific example of position estimation according to a seventh embodiment of the present invention; Fig. 33 is a two-dimensional diagram illustrating an indoor parking area in which an array of reference stations is shown, according to another embodiment of the present invention; Fig. 34 is a perspective diagram illustrating a configuration of a reference station according to another embodiment of the present invention; and Fig. 35 is a diagram illustrating a specific example of position estimation according to another embodiment of the present invention. DESCRIPTION OF EMBODIMENTS

[0016] With reference to the drawings, several embodiments of the present invention are explained below. (First embodiment)

[0017] First, a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 9 explained.

[0018] Fig. 1 is a diagram illustrating a configuration of a wireless positioning system 1 according to the first embodiment. As shown in Fig. 1, the wireless positioning system 1 of the present embodiment includes a plurality of reference stations 2 (in Fig. 1 two reference stations 2a and 2b are shown), several vehicle-mounted devices (in Fig. 1 shows three vehicle-mounted devices (3a, 3b, and 3c) and a management server (4). Reference stations (2) are scattered in an area without GPS coverage to perform direct wireless communication. The vehicle-mounted devices are each installed in a motor vehicle to perform direct wireless communication. The management server (4) manages data for measuring the position of each vehicle-mounted device (3).

[0019] The reference station 2 periodically transmits a radio beacon including identification information of the reference station 2 to the surrounding motor vehicles using a direct wireless communication function. Of the plurality of reference stations 2a, 2b and 2c, some (in Fig. 1 the reference station 2b) is configured to perform data communication with the management server by means of a wireless wide area communication network NW (for example, a mobile phone communication network).

[0020] As in Fig. 2, the vehicle-mounted device 3 includes a vehicle speed sensor 11, a position detector 12, a direct wireless communication device 13, a wide area wireless communication device 14, and a control unit 15.

[0021] Of these components, the vehicle speed sensor 11 detects the speed of the vehicle that has the vehicle sensor 11 installed. The detection results of the vehicle speed sensor 11 are input to the control unit 15.

[0022] The position detector 12 is configured with a GPS receiver and multiple sensors. The GPS receiver receives a satellite signal transmitted from a GPS satellite. The multiple sensors include, for example, a distance sensor that detects a travel distance (movement distance) of the vehicle that has the in-vehicle device 3 installed (hereinafter referred to as "the subject vehicle") based on the rotation of the subject vehicle, and an azimuth sensor. Based on the signals obtained from these sensors, the position detector 12 detects the position and traveling direction of the subject vehicle. The detection results of the position detector 12 are input to the control unit 15.

[0023] The device 13 performs direct wireless communication with the reference station 2.

[0024] The wireless wide area communication device 14 performs data communication with the management server via the wireless wide area communication network NW.

[0025] The control unit 15 includes a central processing unit (CPU) 21, a read-only memory (ROM) 22, and a random access memory (RAM) 23, and controls the communication devices 13 and 14 by allowing the CPU 21 to execute processing based on a program stored in the ROM 22.

[0026] As in Fig. As shown in Figure 3, the management server 4 includes a wireless wide area communication device 31 and a control unit 32. Of these components, the wireless wide area communication device 31 communicates with the reference station 2 and the in-vehicle device 3 via the wireless wide area communication network NW. The control unit 32 includes a CPU 41, a ROM 42, and a RAM 43, and controls the wireless wide area communication device 31 by allowing the CPU 41 to execute processing based on a program stored in the ROM 42. The RAM 43 of the control unit 32 stores reference trajectory information (explained below) regarding the plurality of reference stations 2.

[0027] In the wireless positioning system 1 configured as described above, the in-vehicle device 3 performs position estimation processing, which will be explained later. The management server 4 performs trajectory update processing, which will be described later.

[0028] First, according to Fig. 4 below explains steps of the position estimation processing executed by the CPU 21 of the in-vehicle device 3. The position estimation processing is repeatedly executed while the CPU 21 is activated.

[0029] When executing the position estimation processing, the CPU 21 first determines at step S10 whether or not a connection is established with the management server 4 so that the wide area wireless communication device 14 can communicate with the management server 4. If no connection is established with the management server 4 (NO at step S10), control proceeds to step S40. On the other hand, if the connection with the management server 4 is established (YES at step S10), control proceeds to step S20.

[0030] At step S20, when there is a test trajectory (described later) that has not been transmitted to the management server 4, the CPU 21 transmits test trajectory information indicating the non-transmitted test trajectory to the management server 4 together with the identification information of the reference station 2 and the information indicating the type of the own vehicle, traveling direction (described later), and current time.

[0031] Then, at step S30, the CPU 21 acquires reference trajectory information from the management server 4. The reference trajectory information indicates a reference trajectory of the reference station 2, which is within a predetermined distance (for example, 1 km in the present embodiment) from the current location, in the vicinity of the road on which the vehicle (own vehicle) equipped with the vehicle-mounted device 3 is traveling.

[0032] The acquired reference trajectory information is stored in the RAM 23 and processing continues with step S40. The reference trajectory information of the reference station 2 is stored for each vehicle type and for each travel direction (see Fig. 6). The direction of travel is used here to distinguish between driving in an entry lane and driving in an exit lane of the road.

[0033] From multiple pieces of reference trajectory information regarding the reference stations 2, the CPU 21 of the in-vehicle device 3 acquires only reference trajectory information regarding the vehicle type of the own vehicle and the traveling direction of the own vehicle from the management server. However, if the reference trajectory information of the reference station 2 was acquired in the past and the reference trajectory information has not been updated since the previous acquisition, no reference trajectory information is acquired.

[0034] The reference trajectory gives a relationship between driving distance and test quantity (compare Fig. 5). The driving distance refers to a distance traveled by the host vehicle on the road in the vicinity of the reference station from a point closest to reference station 2, which is a base point (hereinafter referred to as a reference driving distance).

[0035] The test quantity is associated with the reference station 2 (in the present embodiment, the test quantity refers to a received signal strength indicator (RSSI) of a radio signal that the vehicle-mounted device 3 has received from the reference station 2). The test quantity is maximum in the vicinity of the reference station 2 at a point on the road closest to the reference station 2.

[0036] In the reference trajectory, the test quantity does not necessarily decrease gradually as the host vehicle moves away from the point closest to reference station 2. The reference trajectory may have a local maximum (compare ID01 in Fig. 6) reflect the reflection or diffraction caused by a nearby building (compare arrow AL00).

[0037] If control proceeds to step S40, the CPU 21 determines whether or not a beacon has been detected. If no beacon has been detected (NO at step S40), this iteration of the position estimation processing is terminated. On the other hand, if a beacon has been detected (YES at step S40), processing proceeds to step S50. At step S50, the CPU 21 acquires a test quantity (in the present embodiment, the received signal strength RSSI) of the detected beacon.

[0038] At the same time, the CPU 21 calculates a travel distance of the host vehicle from the time at which the beacon was initially detected (hereinafter referred to as a test travel distance) at step S60. Then, a test trajectory (see Fig. 7) which indicates a relationship between test quantity and test driving distance between the time at which the beacon was initially detected and the current time.

[0039] Then, at step S80, the test trajectory generated at step S70 is superimposed on the reference trajectory generated by the reference trajectory information generated at step S30 (see Fig. 7) are obtained, to determine whether or not there is a matching section between them with a degree of matching equal to or greater than a predetermined trajectory matching threshold.

[0040] If there is no matching section with a matching degree equal to or greater than the trajectory matching threshold (NO at step S80), the position estimation processing is terminated once. On the other hand, if there is a matching section with a matching degree equal to or greater than the trajectory matching threshold (YES at step S80), control proceeds to step S90.

[0041] At step S90, the CPU 21 calculates a travel distance TD from an arbitrary characteristic point CP on the reference trajectory to the current time (see Fig. 7). The characteristic point CP corresponds, for example, to a maxima, a minima, a local maxima, or a local minima of the test quantity.

[0042] Then, at step S100, the CPU 21 calculates a current location of the host vehicle on the road on which the host vehicle is traveling based on the travel distance TD from the characteristic point CP at the current time. Then, the position estimation processing is once completed.

[0043] According to Fig. 8, steps of the career update processing executed by the CPU 41 of the management server 4 are explained below. The career update processing is repeatedly executed while the CPU 41 is activated.

[0044] When the trajectory update processing is executed, the CPU 41 first determines whether the test trajectory information has been received from the in-vehicle device 3 at step S210. If no test trajectory information has been received (NO at step S210), the trajectory update processing is terminated once. On the other hand, if test trajectory information has been received (YES at step S210), control proceeds to step S220.

[0045] At step S220, the received test trajectory information is classified and stored based on the identification information of the reference station of the vehicle type of the vehicle that has the in-vehicle device 3 installed and the traveling direction of the vehicle (travel direction into the entry lane or travel direction into the exit lane).

[0046] Then, at step S230, the reference trajectory having the same reference station, vehicle type, and traveling direction as the test trajectory information added at step S220 is updated using the test trajectory added at step S220. Then, the trajectory update processing is completed once.

[0047] Specifically, in the present embodiment, for example, the test trajectories stored up to that point are classified based on the same reference station, the same vehicle type, and the same travel direction. Then, an average value is calculated for the test trajectories of each classification, and the average value is used as a reference trajectory. However, an average value is calculated after removing those test trajectories that have a variance less than or equal to a predetermined distance threshold.

[0048] According to Fig. 9, a specific example of position estimation performed in the wireless positioning system 1 configured as explained above will be explained below.

[0049] As in Fig. As shown in Figure 9, reference stations 2a and 2b are set up along a road R1. Reference stations 2a and 2b are arranged at an interval such that an autonomous sensor of a vehicle can interpolate them with sufficient accuracy. Reference station 2a is not connected to the management server via the wireless wide area communication network NW, while reference station 2b is connected to the management server 4 via the wireless wide area communication network NW.

[0050] A vehicle having the in-vehicle device 3a (hereinafter referred to as a first vehicle) travels on the road R1 in the direction of the reference station 2a. A vehicle having the in-vehicle device 3b installed (hereinafter referred to as a second vehicle) travels on the road R1 away from the reference station 2 in the direction of the reference station 2b. A vehicle having the in-vehicle device 3c installed (hereinafter referred to as a third vehicle) travels on the road R1 away from the reference station 2b.

[0051] The first vehicle traveling in the direction of the reference station 2a obtains from the management server 4 reference trajectory information of the reference station 2a regarding the vehicle type and traveling direction, which are the same as those of the first vehicle (compare the arrow AL01).

[0052] The second vehicle traveling near the reference station 2a generates a test trajectory with respect to the reference station 2a and calculates the current location of the second vehicle based on the results of the agreement between the generated test trajectory and the reference trajectory of the reference station 2a.

[0053] The third vehicle travels near the reference station 2b, which enables a connection to the management server 4. When the third vehicle is connected to the management server 4 via the reference station 2b, the third vehicle transmits the non-transmittable test track information to the management server 4 via the reference station 2b (see arrow AL02).

[0054] In the vehicle-mounted device 3 configured in this manner, the direct wireless communication device 13 receives data transmitted by radio from the reference station 2 by performing direct wireless communication, and then the direct wireless communication device 13 detects the received signal strength RSSI (step S50). Further, the RAM 23 stores reference trajectory information.

[0055] In the reference trajectory information, two or more points of a relationship between the received signal strength (RSSI) and the travel distance are specified. The received signal strength (RSSI) is a signal strength at the time when the direct wireless communication device 13 receives data transmitted by radio from the reference station 2. The travel distance is a distance traveled by the host vehicle on the road in the vicinity of the reference station 2 from a point, i.e., a base point, closest to the reference station 2 (the distance is the above reference travel distance and corresponds to the position on the road).

[0056] Further, the position detector 12 calculates a travel distance of the host vehicle from the time when a radio beacon was initially detected (test travel distance) (step S60). Then, test trajectory information indicating a relationship between a plurality of received signal strengths (RSSI) of the direct wireless communication device 13 and a plurality of test travel distances is generated (step S70).

[0057] Then, the reference trajectory information and the test trajectory information are compared to determine a relationship between the reference travel distance and the test travel distance (step S80). Then, the current location in the in-vehicle device 3 is determined based on the relationship between the reference trajectory information and the test travel information and the currently detected received signal strength RSSI (steps S90 and S100).

[0058] Thus, the current location of the vehicle-mounted device 3 can be determined by performing direct wireless communication with a reference station 2 according to the reference trajectory information.

[0059] Thus, positioning is performed without depending on the density of the reference station 2 around the host vehicle 3. This is because each reference station is fixedly installed at a predetermined installation position, and the relationship between the state (wireless reception state) of receiving data by radio from the reference station 2 and the information (i.e., reference trajectory information) indicating the position on the road formed in the vicinity of the reference station 2 can be determined.

[0060] Reference trajectory information is provided for each vehicle type of the vehicle that has the in-vehicle device 3 installed. Thus, when the test quantity (in the present embodiment, the received signal strength RSSI) changes depending on the vehicle type, the positioning accuracy is prevented from changing greatly depending on the vehicle type.

[0061] Furthermore, reference trajectory information is obtained from the management server 4 by performing wireless communication via the wireless wide area communication network NW with the management server 4 that manages reference trajectory information provided for each of the plurality of reference stations 2 (step S30). Thus, the in-vehicle device 3 is no longer required to prestore a number of pieces of the reference trajectory information provided for the respective reference stations 2.

[0062] Accordingly, the vehicle-mounted device 3 can acquire some pieces of the reference trajectory information from the management server 4 from among the pieces of the trajectory information when necessary, thereby securing the storage space area of ​​the vehicle-mounted device 3.

[0063] Generated test career information is transmitted to the management server 4 by performing wireless communication via the wide area communication network NW (step S20). Thus, the management server 4, which manages reference career information, can update the reference career information using the newly acquired test career information.

[0064] In the above-described embodiment, the vehicle-mounted device 3 is the wireless communication device of the present invention. Similarly, the reference station 2 is the radio transmitter; the direct wireless communication device 13 is the radio communication means or unit; step S50 is the detection means or unit; the RAM 23 is the reference information storage means or unit; step S60 is the distance measuring means; step S70 is the first generation means or unit; step S80 is the relation determination means or unit; and steps S90 and S100 are the position determination means or unit.

[0065] Furthermore, the received signal strength (RSSI) is the radio reception status of the present invention. Similarly, the "travel distance traveled by the host vehicle from a point (i.e., a base point) closest to the reference station 2 on the road in the vicinity of the reference station 2" is the location information (location-related information); the reference trajectory information is the relational reference information; the test travel distance is the relative distance information (relative distance information); and the test trajectory information is the first relational information (first relational measurement information).

[0066] Furthermore, step S30 is the second reference information acquisition means or unit. Similarly, step S20 is the second measurement information transmission means or unit; and the management server 4 is the first management device. (Second embodiment)

[0067] Next, a second embodiment of the present invention will be described with reference to Fig. 10 to Fig. 15 explained.

[0068] Fig. 10 is a diagram illustrating a configuration of a wireless positioning system 110 according to a second embodiment.

[0069] As in Fig. 10, the wireless positioning system 101 of the present embodiment includes a plurality of reference stations 102 (in Fig. 10, two reference stations 102a and 102b are shown) and several vehicle-mounted devices 103 (in Fig. Figure 10 shows three vehicle-mounted devices 103a, 103b, and 103c. Reference stations 102 are scattered in an area without GPS coverage to perform direct wireless communication. Vehicle-mounted devices 3 are each installed in a motor vehicle to perform direct wireless communication.

[0070] The reference station 102 periodically transmits a radio beacon including identification information of the reference station 102 to the motor vehicles around it using a direct wireless communication function.

[0071] As in Fig. As shown in Figure 11, each reference station 102 includes a direct wireless communication device 111 and a control unit 112. Of these components, the direct wireless communication device 111 performs direct wireless communication via the in-vehicle device 103. The control unit 112 includes a CPU 121, a ROM 122, and a RAM 123. The control unit 112 controls the direct wireless communication device 111 by allowing the CPU 121 to execute processing based on a program stored in the ROM 122. In the RAM 123 of the control unit 112, reference trajectory information regarding the reference station 102 that has this control unit 112 installed is classified and stored based on the vehicle type and the traveling direction of the vehicles.

[0072] As in Fig. As shown in FIG. 12, the in-vehicle device 103 includes a vehicle speed sensor 131, a position detector 132, a direct wireless communication device 133, and a control unit 134. Of these components, the vehicle sensor 131, the position detector 132, and the direct wireless communication device 133 are respectively the same as the vehicle speed sensor 11, the position detector 12, and the direct wireless communication device 13 of the first embodiment. Therefore, the description of these components will be omitted. The control unit 134 includes a CPU 141, a ROM 142, and a RAM 143, and controls the direct wireless communication device 133 by allowing the CPU 141 to execute a program stored in the ROM 142.In the wireless positioning system 101 configured as described above, the in-vehicle device 103 performs position estimation processing, which will be described later. The reference station 102 performs trajectory update processing, which will be explained later.

[0073] First, according to Fig. 13, steps of position estimation processing executed by the CPU 141 of the in-vehicle device 103 are explained below. The position estimation processing is repeatedly executed while the CPU 141 is activated.

[0074] When executing position estimation processing, the CPU 141 first determines whether or not a beacon has been detected at step S310. If no beacon has been detected (NO at step S310), control proceeds to step S410. On the other hand, if a beacon has been detected (YES at step S310), control proceeds to step S320.

[0075] At step S320, it is determined whether or not the reference station 102 specified by identification information included in the beacon is the one whose reference trajectory has not yet been acquired by the vehicle-mounted device 103. If the reference station 102 is the one whose reference trajectory has already been acquired (NO at step S320), control proceeds to step S340.

[0076] On the other hand, if the reference station 102 is the one whose reference trajectory has not been acquired (YES at step S320), control proceeds to step S330. At step S330, the CPU 141 transmits a request to transmit reference trajectory information (hereinafter referred to as a reference trajectory request command) to the reference station 102 corresponding to the detected beacon.

[0077] When transmitting the reference trajectory request command, information about the type of vehicle that the in-vehicle device 103 is installed (hereinafter referred to as "the subject vehicle") and information about the traveling direction of the subject vehicle are also transmitted. Then, control proceeds to step S340. In step S340, a test quantity (in the present embodiment, received signal strength RSSI) of the detected radio beacon is acquired.

[0078] At the same time, in step S350, the CPU 141 calculates a travel distance (test travel distance) of the host vehicle from the time at which the radio beacon was initially detected. Then, in step S360, a test travel path (see Fig. 6) which indicates a relationship between test quantity and test driving distance between the time at which the beacon was initially detected and the current time.

[0079] Then, at step S370, if the reference trajectory information corresponding to the detected beacon has already been acquired, the test trajectory generated at step S360 is assigned to the reference trajectory determined by the reference trajectory information (see Fig. 6) to determine whether or not a conformity section exists with a conformity level equal to or greater than a predetermined track conformity threshold.

[0080] If there is no matching section having a matching degree equal to or greater than the trajectory matching threshold value (NO in step S370), control proceeds to step S410. On the other hand, if there is a matching section having a matching degree equal to or greater than the trajectory matching threshold value (YES in step S370), the CPU 141 calculates a travel distance TD (see Fig. 6) from any characteristic point CP on the reference trajectory to the present time.

[0081] Then, at step S390, the CPU 141 calculates the current location of the host vehicle on the road on which the host vehicle is traveling based on the travel distance TD between the characteristic point and the current point. Further, at step S400, the CPU 141 transmits test trajectory information indicating the one untransmitted test trajectory to the reference station 102 corresponding to the detected beacon, along with information indicating the vehicle type of the host vehicle, the traveling direction of the host vehicle, and the current time. Then, control proceeds to step S410.

[0082] At step S410, it is determined whether or not the reference trajectory information has been received from the reference station 102 corresponding to the detected beacon. If reference trajectory information has not been received (NO at step S410), the position estimation processing is terminated once. On the other hand, if the reference trajectory information has been received (YES at step S410), control proceeds to step S420. At step S420, the received reference trajectory information is stored in the RAM 143, and the position estimation processing is terminated once.

[0083] According to Fig. 14, steps of the trajectory update processing executed by the CPU 121 of the reference station 102 are described below. The trajectory update processing is repeatedly executed while the CPU 121 is activated.

[0084] When executing the trajectory update processing, the CPU 121 first determines whether or not a reference trajectory request command has been received from the in-vehicle device 103 at step S510. If the reference trajectory request command has not been received (NO at step S510), the processing proceeds to step S530. On the other hand, if the reference trajectory request command has been received (YES at step S510), the processing proceeds to step S520.

[0085] At step S520, the CPU 121 transmits reference trajectory information to the in-vehicle device 103. The reference trajectory information includes a reference trajectory including the vehicle type and traveling direction specified by the vehicle type information and the traveling direction information received along with the reference trajectory request command, respectively. Then, control proceeds to step S530.

[0086] At step S530, the CPU 121 determines whether or not the test run information has been received from the in-vehicle device 103. If test run information has not been received (NO at step S530), the run update processing is terminated once. On the other hand, if test run information has been received (YES at step S530), control proceeds to step S540.

[0087] At step S540, the CPU 121 determines whether or not the received test path information is continuation information of a past test session generated at step S550, which will be described later. If the received test path information is not the continuation information (NO at step S540), control proceeds to step S550, where a new test session is generated.

[0088] The test session corresponds to a storage area provided for storing test trajectory information transmitted from a specific in-vehicle device 103 to the reference station 102 from when the in-vehicle device 103 approaches the reference station 102 until it moves away from it. The test session is provided with the vehicle type information and the travel direction information corresponding to the test trajectory information received at step S530.

[0089] Then, at step S560, a session timer is activated, and control continues with step S580. For example, the session timer count is incremented every 100 ms. Upon activation, the count is incremented starting from zero.

[0090] On the other hand, if the received test run information is continuation information (YES at step S540), control proceeds to step S570, where the session timer is reactivated. Then, control proceeds to step S580.

[0091] In step S580, the received test track information is stored in the test session. Then, in step S590, the CPU 121 determines whether the session timer count is equal to or greater than a predetermined elapsed time limit. In other words, the CPU 121 determines whether the elapsed time since the previous reception of the test track information has exceeded the time corresponding to the elapsed time limit.

[0092] If the session timer count is less than the expiration threshold (NO at step S590), the career update processing is terminated once. On the other hand, if the expiration timer count is equal to or greater than the expiration threshold (YES at step S590), control proceeds to step S600.

[0093] At step S600, the test trajectory information stored in the test session is classified and stored in the RAM 123 based on the vehicle type of a vehicle having the in-vehicle device 103 installed and a traveling direction of the vehicle (traveling direction in the entry lane or traveling direction in the exit lane) according to the vehicle type information and the traveling direction information set in the test session.

[0094] Then, at step S610, similar to step S230 of the first embodiment, the reference trajectory having a vehicle type and vehicle direction that are the same as those of the test trajectory information added at step S600 is updated using the test trajectory added at step S600. Further, at step S620, the incrementing of the session timer count is stopped, and the trajectory update processing is terminated once.

[0095] According to Fig. 15, a specific example of position estimation performed in the wireless positioning system 101 as described above will be explained below.

[0096] As in Fig. As shown in Figure 15, reference stations 102a and 102b are set up along a road R2. Reference stations 102a and 102b are arranged at an interval that a vehicle's autonomous sensor can interpolate with sufficient accuracy.

[0097] A vehicle having the in-vehicle device 103a installed (hereinafter referred to as the first vehicle) travels on the road R2 toward the reference station 102a. A vehicle having the in-vehicle device 103b installed (hereinafter referred to as the second vehicle) travels on the road R2 away from the reference station 102a toward the reference station 102b.

[0098] When the first vehicle approaches the reference station 102a such that a radio beacon can be detected by the reference station 102a, the first vehicle obtains reference trajectory information from the reference station 102a regarding the vehicle type and direction of travel, which is the same as that of the first vehicle (see arrow AL11). Likewise, the first vehicle transmits untransmitted test trajectory information to the reference station 102a (see arrow AL12).

[0099] The second vehicle traveling near the reference station 102a generates a test trajectory relative to the second reference station 102a and calculates the current location of the second vehicle based on the matching results between the generated test trajectory and the reference trajectory of the reference station 102a. At the same time, the second vehicle transmits untransmitted test trajectory information to the reference station 102a (see arrow AL13).

[0100] In the vehicle-mounted device 103 configured as described above, reference trajectory information transmitted from the reference station 102 is acquired using the direct wireless communication device 133 (steps S320, S330, S410, and S420). Thus, the reference trajectory information is acquired without using a communication device that performs wireless communication via the wireless wide area communication network NW.

[0101] Further, test track information generated using the direct wireless communication device 133 is transmitted to the reference station 102 (step S400). Thus, the reference station 102, in which reference track information is stored, updates the reference track information using the newly acquired test track information.

[0102] In the above-described embodiment, the vehicle-mounted device 103 is the wireless communication device of the present invention. Similarly, the reference station 102 is the radio transmitter; the direct wireless communication device 133 is the radio communication means or unit; step S340 is the detection means or unit; the RAM 143 is the reference information storage means or unit; step S350 is the distance measuring means or unit; step S360 is the first generation means or unit; step S370 is the relation determination means or unit; and steps S380 and S390 are the position determination means or unit.

[0103] Steps S320, S330, S410, and S420 represent the first reference information acquisition means or unit. Similarly, step S400 represents the first measurement information transmission means or unit. (Third embodiment)

[0104] Next, a third embodiment of the present invention will be described with reference to Fig. 16 to Fig. 18 explained.

[0105] In the third embodiment, only differences from the second embodiment are explained. Likewise, in the third embodiment, components that are identical or similar to those of the second embodiment are provided with the same reference numerals for simplicity.

[0106] As in Fig. As shown in Figure 16, the wireless positioning system 101 of the third embodiment differs from the second embodiment in that the reference stations 102a and 102b are set along a road R3 having two lanes in each direction, and the position estimation processing and trajectory update processing are changed. The remaining configuration is similar to that of the second embodiment.

[0107] In the RAM 123 of the control unit 112, pieces of reference trajectory information regarding the reference station 102 that the control unit 112 has installed are classified and stored based on the vehicle type and the traveling direction of vehicles. Each piece of reference trajectory information includes a reference trajectory of each of the first lane and the second lane that configure the two lanes of each direction (compare the reference trajectories TR1 and TR2 in Fig. 16).

[0108] As in Fig. As shown in Fig. 17, in the position estimation processing according to the third embodiment, steps S360 and S380 to S400 are omitted, and steps S710 to S750 are added. The remaining steps are similar to those of the second embodiment.

[0109] After completing step S350, control proceeds to step S710. In step S710, the CPU of the vehicle-mounted device 103 generates a test track (see Fig. 6), which indicates a relationship between the test quantity and the test travel distance between the time a radio beacon was initially detected and the current time. The test quantity also includes the speed and steering angle of the host vehicle at the time the test quantity was detected. When step S710 is completed, control proceeds to step S370.

[0110] At step S370, if there is a matching section having a matching degree equal to or greater than the trajectory matching threshold value (YES at step S370), control proceeds to step S720.

[0111] At step S720, the lane corresponding to the reference trajectory including the over-matching section with a matching degree equal to or greater than the trajectory matching threshold value is set as a lane on which the subject vehicle is currently traveling.

[0112] Then, at step S730, the CPU 141 calculates a travel distance TD between an arbitrary characteristic point CP and the current time on the reference trajectory corresponding to the set track.

[0113] Then, at step S740, the CPU 141 calculates the current location of the host vehicle on the road on which the host vehicle is traveling, based on the traveling distance TD between the characteristic time point CP and the current time point.

[0114] Then, at step S750, the CPU 141 transmits test trajectory information indicating a non-transmitted test trajectory to the reference station 102 corresponding to the detected beacon, along with information indicating the vehicle type and traveling direction of the host vehicle, and the current time. Then, control proceeds to step S410.

[0115] As in Fig. As shown in Fig. 18, in the career update processing of the third embodiment, step S610 is omitted and step S810 is added. The remaining steps are similar to those of the second embodiment.

[0116] Specifically, when step S600 is completed, control proceeds to step S810. At step S810, similar to step S230 of the first embodiment, the CPU 121 of the reference station 102 updates the reference trajectory having the same vehicle type and traveling direction as those of the test trajectory information added at step S600 using the test trajectory added at step S600. However, the reference trajectory having the same vehicle type and traveling direction includes the reference trajectory of the first lane and the reference trajectory of the second lane.

[0117] Accordingly, at step S810, the CPU 121 determines whether the reference trajectory corresponds to the test trajectory of the first lane or the test trajectory of the second lane based on the speed information and steering angle information added to the test quantity of the test trajectory, thereby updating the reference trajectory. When step S810 is completed, control proceeds to step S620.

[0118] In the in-vehicle device 103 configured as described above, reference trajectory information is provided for each lane of the road R3. Thus, by comparing the reference trajectory information provided for each lane of the road R3 with the test trajectory information, the lane on which the vehicle that has the in-vehicle device 103 installed (the subject vehicle) is traveling can be specified. (Fourth embodiment)

[0119] Next, a fourth embodiment of the present invention will be described with reference to Fig. 19 and Fig. 20 explained.

[0120] The fourth embodiment will be explained with a focus on the differences from the first embodiment. Likewise, in the fourth embodiment, components that are identical or similar to those in the first embodiment are denoted by the same reference numerals to omit unnecessary explanation.

[0121] The wireless positioning system 1 of the fourth embodiment is similar to that of the first embodiment except that the position estimation processing and the trajectory update processing are changed.

[0122] First, as in Fig. As shown in Fig. 19, in the position estimation processing according to the fourth embodiment, step S20 is omitted, but step S900 is added instead. The remaining steps are similar to those of the first embodiment.

[0123] Specifically, when step S10 is completed, control proceeds to step S900. At step S900, if there is any test trajectory that has not yet been transmitted to the management server 4, the CPU 21 of the in-vehicle device 3 transmits test trajectory information indicating a non-transmitted test trajectory to the management server 4 along with identification information of the reference station 2, information indicating the vehicle type and traveling direction of the host vehicle, and the current time.

[0124] Further, the CPU 21 transmits driving trajectory information to the management server 4. The driving trajectory information indicates a driving trajectory the vehicle traveled during a period including the period corresponding to the non-transmitted test trajectory and the periods before and after the non-transmitted test trajectory. When step S900 is completed, control proceeds to step S30.

[0125] In the career update processing of the fourth embodiment, steps S210 to S230 are omitted, but steps S910 to S960 are added instead. The remaining steps are similar to those of the first embodiment.

[0126] Specifically, when the trajectory update processing is executed, the CPU 41 of the management server first determines at step S910 whether or not test trajectory information and driving trajectory information have been received from the vehicle-mounted device 3.

[0127] If the test trajectory information and the running trajectory information have not been received (NO at step S910), the trajectory update processing is terminated once. On the other hand, if the test trajectory information and the running trajectory information have been received (YES at step S910), the processing proceeds to step S920.

[0128] At step S920, the CPU 41 determines whether or not the received test run information regarding the reference station has already been registered. Specifically, when the identification information of the reference station 2 is added to the test run information, the CPU determines that the test run information regarding the reference station has already been registered.

[0129] When the identification information of the reference station 2 is not added to the test trajectory information, the CPU 41 makes a determination by comparing the reference trajectory information stored in the management server 4 with the received test trajectory information and running trajectory information.

[0130] If the received test trajectory information regarding the reference station has already been registered (YES in step S920), control proceeds to step S930. In step S930, the received test trajectory information is classified and stored based on the identification information of the reference station, the vehicle type of the vehicle that has the in-vehicle device installed, and the traveling direction of the vehicle.

[0131] Then, at step S940, the CPU 41 updates the reference trajectory with the same reference station, vehicle type, and traveling direction as the added trajectory information using the test trajectory added at step S930. Then, the trajectory update processing is terminated once.

[0132] On the other hand, if the received test trajectory information is not about the reference station as already registered (NO at step S920), control proceeds to step S950. At step S950, identification information of the reference station is newly assigned to the received test trajectory information and travel trajectory information, followed by classifying and storing the trajectory information and travel trajectory information based on the identification information of the reference station, the vehicle type of the vehicle that has the vehicle-mounted device 3 installed, and the traveling direction of the vehicle.

[0133] Then, at step S960, a reference trajectory is newly generated based on the received test trajectory information and travel trajectory information, followed by classifying and storing the reference trajectory based on the identification information of the reference station, the vehicle type of the vehicle, and the traveling direction of the vehicle. Then, the trajectory update processing is completed.

[0134] According to Fig. 21, a specific example in which a reference trajectory is newly entered into the wireless positioning system 1 configured as explained above will be explained below.

[0135] As in Fig. As shown in Figure 21, a vehicle having the on-vehicle device 3a installed (hereinafter referred to as the first vehicle) travels along a road R4 and turns left at an intersection CP of the road R4 (see the travel path VP41). An unregistered reference station 2d is established at a position along the road R4 just before the intersection CP.

[0136] The first vehicle, when traveling along the road R4 and close to the reference station 2d, can detect a radio beacon from the reference station 2d to thereby generate a test trajectory PT41 (compare Fig. 21).

[0137] The management server 4 determines the point of the left turn on the running path VP41 as the position of an intersection based on receiving the test running path information indicating the test running path TP41 and the running path indicating the running path VP41.

[0138] Then, using a position P41 of the intersection as a reference, the management server 4 can specify a position P42 (characteristic point CP42) on the road R4 at which the test quantity of the test trajectory PT41 is maximum.

[0139] Thus, the management server 4 can newly register a reference trajectory indicating a relationship between test quantity and position on the road R4 as a reference trajectory ST41 of the reference station 2d (cf. Fig. 21).

[0140] After the reference trajectory ST40 of the reference station 2d has been entered, a vehicle having the on-vehicle device 3b installed (hereinafter referred to as the second vehicle) travels on the road R4 and travels straight ahead at the intersection CS of the road R4 (compare the travel trajectory VP42).

[0141] In this case, the vehicle-mounted device 3b compares test path information containing a test path PT42 (compare Fig. 2) generated using a radio beacon from the reference station 2d, with the reference trajectory SC41 of the reference station 2d, to thereby specify the position P42 on the road R4 at which the test quantity is maximum. Thereafter, the vehicle-mounted device 3b obtains a travel distance VE41 from the position 42 using an autonomous sensor, to thereby determine a current location 43 (cf. Fig. 21) on the R4 road.

[0142] A WAN (wide area network) base station WS (compare Fig. 21) which is not power-controlled or current-controlled can also be entered as a reference station.

[0143] The vehicle-mounted device 3 configured as described above transmits driving trajectory information corresponding to the test trajectory information to the management server 4 (step S900). Thus, the management server can generate a reference trajectory indicating a relationship between the test trajectory and the position on the road R4 based on the received test trajectory information and driving trajectory information. Accordingly, the reference trajectory information of the reference station 2 not registered in the management server 4 can be newly registered.

[0144] In the above-described embodiment, step S900 is the trajectory transmission means or unit. Similarly, the trajectory information is the movement trajectory information. (Fifth embodiment)

[0145] Next, a fifth embodiment of the present invention will be described with reference to Fig. 22 to Fig. 29 explains.

[0146] As in Fig. 22, a wireless positioning system 201 of the present embodiment includes a plurality of reference stations 202 (two reference stations 202a and 202b are shown in Fig. 22), a vehicle-mounted device 203 (in Fig. 22 shows three vehicle-mounted devices 203a, 203b, and 203c and a management server 204. The plurality of reference stations 202 are scattered along a road. The vehicle-mounted device 3 is installed in a vehicle to perform direct wireless communication. The management server 204 manages data for measuring an inter-vehicle distance.

[0147] The reference station 202 periodically transmits a radio beacon including identification information of the reference station 202 to the surrounding vehicles using a direct wireless communication function. Likewise, the plurality of reference stations 202 are each configured to perform data communication with the management server 204 via a wireless wide area communication network NW (e.g., a mobile phone communication network).

[0148] As in Fig. 23, the vehicle-mounted device 203 includes a vehicle speed sensor 11, a position detector 12, a direct wireless communication device 213, a wide area wireless communication device 214, a radar device 215, and a control unit 216.

[0149] Of these components, the direct wireless communication device 213 performs direct wireless communication with the reference station 202 and the on-vehicle device 203 of another vehicle.

[0150] The wireless wide area communication device 214 performs data communication with the management server 204 via the wireless wide area communication network NW.

[0151] The radar device 215 transmits radar waves of a millimeter wave band in a forward direction of the vehicle that has the vehicle-mounted device 203 installed (hereinafter referred to as “own vehicle”) and receives reflected radar waves to detect a distance to a point where the radar waves were reflected.

[0152] The control unit 216 includes a CPU 221, a ROM 222, and a RAM 223. The control unit 216 allows the CPU 21 to execute a program stored in the ROM 222, thereby controlling the communication devices 213 and 214 and the radar device 215.

[0153] The control unit 216 performs control under which the information indicating the vehicle type and the speed of the vehicle is mutually transmitted / received between the in-vehicle device 203 of the own vehicle and the in-vehicle device 203 of another vehicle using direct wireless communication.

[0154] As in Fig. 24, the management server 204 includes a wide area wireless communication device 231 and a control unit 232. Of these components, the wide area wireless communication device 231 performs data communication with the reference station 202 and the vehicle-mounted device 203 via the wide area wireless communication network NW.

[0155] The control unit 232 includes a CPU 241, a ROM 242, and a RAM 243. The control unit 232 allows the CPU 241 to execute processing based on a program stored in the ROM 242, thereby controlling the wireless wide area communication device 231. Likewise, the RAM 243 of the control unit 232 stores reference trajectory information regarding an inter-vehicle distance (explained later).

[0156] Hereinafter, the reference trajectory information regarding inter-vehicle distance is referred to as inter-vehicle distance reference trajectory information. The inter-vehicle distance reference trajectory information is provided for each combination of the vehicle type of the own vehicle and the vehicle type of a preceding vehicle.

[0157] In the wireless positioning system 201 configured as described above, the in-vehicle device 203 performs inter-vehicle distance estimation processing, which will be explained later. The management server 204 performs trajectory update processing, which will be explained later.

[0158] First, according to Fig. 25, steps of inter-vehicle distance estimation performed by the CPU 221 of the in-vehicle device 203 are explained below. The inter-vehicle distance estimation processing is repeatedly executed while the CPU 221 is activated.

[0159] When the inter-vehicle distance estimation processing is executed, the CPU 221 first determines at step S1010 whether or not a connection is established with the management server 204 through the wide area wireless communication device 214 for enabling data communication.

[0160] If no connection to the management server 204 is established (NO at step S1010), control proceeds to step S1040. On the other hand, if the connection to the management server 204 is established (YES at step S1010), control proceeds to step S1020.

[0161] At step S1020, when there is a radar test trajectory (described later) that has not yet been transmitted to the management server 204, the CPU 221 transmits radar test trajectory information indicating a radar test trajectory that has not been transmitted to the management server 4, together with vehicle type information indicating the vehicle type of the own vehicle and preceding vehicle type information indicating the vehicle type of a preceding vehicle.

[0162] Then, at step S1030, the CPU 221 acquires unacquired or unupdated inter-vehicle distance reference trajectory information from the management server 204 and stores the information in the RAM 223.

[0163] Then, control proceeds to step S1040. A reference trajectory with respect to an inter-vehicle distance (hereinafter referred to as an inter-vehicle distance reference trajectory) indicates a relationship between an inter-vehicle distance to a preceding vehicle and a test quantity of a radio beacon received by the preceding vehicle (see Fig. 26). The inter-vehicle distance reference trajectory is provided for each combination of the vehicle type of the own vehicle and the vehicle type of a preceding vehicle.

[0164] At step S1040, the CPU 221 determines whether or not a beacon has been detected by the in-vehicle device 203 from another vehicle. If no beacon has been detected (NO at step S1040), control proceeds to step S1120. On the other hand, if a beacon has been detected (YES at step S1040), control proceeds to step S1050. At step S1050, the test quantity (received signal strength RSSI in the present embodiment) of the detected beacon is acquired.

[0165] At the same time, at step S1060, the CPU 221 calculates an inter-vehicle distance between the host vehicle and the preceding vehicle with respect to the time point at which the beacon was initially detected (hereinafter referred to as a test inter-vehicle distance).

[0166] Then, at step S1070, the CPU 221 generates a test track (see Fig. 27), which indicates a relationship between test quantity and test inter-vehicle distance (hereinafter referred to as inter-vehicle distance test trajectory).

[0167] The test inter-vehicle distance is calculated based on the information regarding the traveling speed of the own vehicle and the information regarding the traveling speed of the preceding vehicle obtained by direct wireless communication with the preceding vehicle.

[0168] For example, a radio beacon may be initially detected by the on-vehicle device 203 of another vehicle, and the inter-vehicle distance at that time is indicated by D0 (compare Fig. 27) (corresponds to a predetermined time).

[0169] Then, when the host vehicle decelerates or the preceding vehicle accelerates, the test inter-vehicle distance becomes longer than D0 depending on the amount of speed change. In contrast, when the host vehicle accelerates or the preceding vehicle decelerates, the inter-vehicle distance becomes shorter than D0 depending on the amount of speed change. However, since the value of D0 is unknown, the test quantity cannot be correlated with the actual inter-vehicle distance in the inter-vehicle distance test trajectory.

[0170] Then, at step S1080, the CPU 221 measures an inter-vehicle distance between the host vehicle and the preceding vehicle using the radar device 215 (hereinafter referred to as radar inter-vehicle distance). Then, at step S1090, the CPU 221 generates a test trajectory indicating a relationship between the test quantity and the radar inter-vehicle distance (hereinafter referred to as radar test trajectory).

[0171] Thereafter, at step S1100, the CPU 221 extracts the inter-vehicle distance reference trajectory information specified by the combination of the vehicle type of the own vehicle and the vehicle type of the preceding vehicle from a plurality of pieces of already acquired inter-vehicle distance reference trajectory information.

[0172] Then, the CPU 221 superimposes the inter-vehicle distance test trajectory generated at step S1070 on the inter-vehicle distance reference trajectory indicated by the extracted inter-vehicle distance reference trajectory information to determine whether or not there is a matching portion having a matching degree equal to or greater than a predetermined trajectory matching threshold.

[0173] If there is no matching section with a matching degree equal to or greater than the trajectory matching threshold (NO at step S1100), control proceeds to step S1120. On the other hand, if there is a matching section with a matching degree equal to or greater than the trajectory matching threshold (YES at step S1100), control proceeds to step S1110.

[0174] At step S1110, the CPU 221 sets the value of D0 based on the results of superimposing the inter-vehicle distance reference trajectory and the inter-vehicle distance test trajectory, correlating the test quantity with the actual inter-vehicle distance in the inter-vehicle distance test trajectory. Thus, the actual inter-vehicle distance is determined based on the current test quantity, and then control proceeds to step S1120.

[0175] At step S1120, the CPU 221 determines whether or not a radio beacon has been detected by the reference station 202. If no radio beacon has been detected by the reference station 202 (NO at step S1120), the inter-vehicle distance estimation processing is terminated once. On the other hand, if a radio beacon has been detected by the reference station 202 (YES at step S1120), control proceeds to step S1130.

[0176] At step S1130, the CPU 221 transmits information to the management server 204 via the reference station 202. The information includes the information regarding the test quantity of a radio beacon received from the in-vehicle device 203 of another vehicle (test quantity information), the information regarding the current location of the own vehicle, the information regarding the vehicle type of the own vehicle, the information regarding the vehicle type of the preceding vehicle, and the information regarding the current time. Then, the inter-vehicle distance estimation processing is terminated once.

[0177] According to Fig. 28, steps of the career update processing executed by the CPU 241 of the management server are explained below. The career update processing is repeatedly executed while the CPU 241 is activated.

[0178] When the trajectory update processing is executed, the CPU 241 first determines at step S1210 whether or not radar test trajectory information has been received from the on-vehicle device 203.

[0179] If no radar test trajectory information has been received (NO at step S1210), processing proceeds to step S1240. On the other hand, if radar test trajectory information has been received from the in-vehicle device 203 (YES at step S1210), the CPU 241 classifies the received radar test trajectory information based on the combination of the vehicle type of the host vehicle and the vehicle type of the preceding vehicle, and stores the classified data in the RAM 243.

[0180] Then, at step S1230, the CPU 241 updates the inter-vehicle distance reference trajectory in which the combination between the vehicle type of the own vehicle and the vehicle type of the preceding vehicle is the same as that of the radar test trajectory information added at step S1220, based on the radar trajectory information added at step S1220.

[0181] Then, control proceeds to step S1240. The update is performed by statistically processing data based on conditions such as the vehicle type of the host vehicle, the vehicle type of the preceding vehicle, the road curvature, and the lane.

[0182] At step S1240, the CPU 241 determines whether or not test quantity information has been received from the in-vehicle device 203. If no test quantity information has been received (NO at step S1240), the trajectory update processing is terminated once. On the other hand, if test quantity information has been received from the in-vehicle device 203 (YES at step S1240), control proceeds to step S1250.

[0183] At step S1250, the CPU 241 stores the received test quantity information together with the simultaneously received information regarding the current location of the vehicle, the vehicle type information of the own vehicle, the vehicle type information of the preceding vehicle, and the current time information.

[0184] Then, in step S1260, the inter-vehicle distance reference trajectory is updated based on the information stored in step S1250. Then, the trajectory update processing is completed. The update is performed by statistically processing data based on conditions such as the vehicle type of the host vehicle, the vehicle type of the preceding vehicle, the road curvature, and the lane.

[0185] According to Fig. 29, a specific example of the inter-vehicle distance estimation performed in the wireless positioning system 201 configured as described above will be explained below.

[0186] As in Fig. As shown in Fig. 29, a vehicle having the in-vehicle device 203a installed (hereinafter referred to as the first vehicle) and a vehicle having the in-vehicle device 203b installed (hereinafter referred to as the second vehicle) travel near the reference station 202a. The second vehicle travels in front of the first vehicle while wireless communication is being performed between them (refer to arrow AL51).

[0187] In this case, each of the vehicle-mounted devices 203a and 203b transmits test quantity information and the like to the management server 204 via the reference station 202a (see arrows AL52, AL53, and AL54).

[0188] Furthermore, a vehicle that has the in-vehicle device 203d installed (hereinafter referred to as the fourth vehicle) travels in front of a vehicle that has the in-vehicle device 203c installed (hereinafter referred to as the third vehicle). No reference station 202 is set up in the vicinity of the third vehicle and the fourth vehicle.

[0189] The third vehicle detects an inter-vehicle distance between the third and fourth vehicles using the radar device while conducting direct wireless communication with the fourth vehicle (see arrow AL55). In this case, the in-vehicle device 203c transmits test trajectory information and the like to the management server 204 (see arrow AL56).

[0190] Then, the management server 204 creates an inter-vehicle distance trajectory and updates the inter-vehicle distance trajectory using the test quantity information, the test trajectory information, and the like received from the vehicle-mounted device 203.

[0191] Furthermore, a vehicle that has the in-vehicle device 203f installed (hereinafter referred to as the sixth vehicle) travels in front of a vehicle that has the in-vehicle device 203e installed (hereinafter referred to as the fifth vehicle). No reference station 202 is set up in the vicinity of the fifth vehicle and the sixth vehicle.

[0192] Direct wireless communication is performed between the fifth vehicle and the sixth vehicle (see arrow AL57). In this case, the fifth vehicle compares the inter-vehicle distance test trajectory generated by direct wireless communication with the sixth vehicle with the inter-vehicle distance reference trajectory already obtained from the management server 204. Thus, the inter-vehicle distance between the fifth and sixth vehicles can be estimated without using the radar device.

[0193] In the in-vehicle device 203 configured as described above, the direct wireless communication device 213 performs direct wireless communication to receive data transmitted from the in-vehicle device 203 of another vehicle that transmits data by radio transmission. Then, the received signal strength RSSI of the direct wireless communication device 213 is detected (step S1050).

[0194] Furthermore, the RAM 223 stores inter-vehicle distance reference trajectory information. Two or more points are provided in this information to represent a relationship between the received signal strength RSSI and the relative distance between the own-vehicle device of another vehicle and the in-vehicle device 203 of the own vehicle. In this case, the received signal strength RSSI indicates the strength when data transmitted from the in-vehicle device 203 of another vehicle is received by the direct wireless communication device 213 through radio reception.

[0195] Further, an inter-vehicle distance (test inter-vehicle distance) between the host vehicle and the preceding vehicle is calculated with reference to the time at which a radio beacon was initially detected (step S1060). Then, inter-vehicle distance test trajectory information indicating a relationship between a plurality of received signal strengths (RSSI) of the direct wireless communication device 213 and a plurality of test inter-vehicle distances is generated (step S1070).

[0196] The inter-vehicle distance reference trajectory information is compared with the inter-vehicle distance test trajectory information to determine a relationship between relative distance and test inter-vehicle distance (step S1100).

[0197] Then, an inter-vehicle distance to the on-vehicle device 203 of another vehicle is determined based on the relationship between the inter-vehicle distance reference trajectory information and the inter-vehicle distance test trajectory information and the currently detected received signal strength RSSI (step S1110).

[0198] Thus, when the in-vehicle device 203 of the own vehicle moves into the vicinity of the in-vehicle device 203 of other vehicles, it can perform direct wireless communication with an in-vehicle device 203 corresponding to the inter-vehicle distance trajectory information (i.e., the in-vehicle device 203 installed in another vehicle). Thus, a relative distance between the in-vehicle device 203 of the own vehicle and another vehicle can be determined.

[0199] Inter-vehicle distance reference trajectory information is acquired from the management server 204 by performing wireless communication via the wireless wide area communication network NW with the management server 204 that manages the inter-vehicle distance reference trajectory information (step S1030).

[0200] Thus, a necessary piece of inter-vehicle distance reference trajectory information can be obtained by the management server 204 from multiple pieces of inter-vehicle distance reference trajectory information provided based on a combination of the vehicle type of the own vehicle and the vehicle type of a preceding vehicle. Accordingly, the data storage area of ​​the in-vehicle device 230 can be established.

[0201] The in-vehicle device 203 is installed in a vehicle (the host vehicle) traveling on a road. Thus, the host vehicle has the radar device 215 installed, which measures a relative distance to a vehicle (a leading vehicle) traveling in front of the host vehicle. The host vehicle's in-vehicle device 203 generates radar test trajectory information indicating a relationship between the detected received signal strength (RSSI) and the radar inter-vehicle distance measured by the radar device 215 (step S1090).

[0202] The in-vehicle device 203 of the own vehicle performs wireless communication via the wireless wide area communication network NW to transmit the generated radar test trajectory information to the management server 204 (step S1020). Thus, the management server 204, which manages the inter-vehicle distance reference trajectory information, uses the newly acquired radar test trajectory information to update the inter-vehicle distance reference trajectory information.

[0203] In the above-described embodiment, the in-vehicle device 203 is the wireless communication device of the present invention. Similarly, the in-vehicle device 203 of another vehicle is the radio transmitter; the direct wireless communication device 213 is the radio communication means or unit; step S1050 is the detection means or unit. The RAM 223 is the reference information storage means or unit; step S1060 is the distance measuring means or unit; step S1070 is the first generation means or unit; step S1100 is the relation determination means or unit; and step S1110 is the position determination means or unit.

[0204] Furthermore, the received signal strength (RSSI) is the radio reception state of the present invention. Similarly, the relative distance between the own-vehicle device 203 of another vehicle and the own-vehicle in-vehicle device 203 is the position-related information; the inter-vehicle distance reference trajectory information is the relational reference information; the test inter-vehicle distance is the relative distance information; and the inter-vehicle distance test trajectory information is the first relational information.

[0205] Furthermore, step S1030 is the third reference information acquisition means or unit. Similarly, step S1090 is the second generation means or unit; step S1020 is the third measurement information transmission means or unit; the radar device 215 is the relative distance measuring device; the radar test trajectory information is the second relation information (second relation measurement information); and the management server 204 is the second management device. (Sixth embodiment)

[0206] Next, a sixth embodiment of the present invention will be described with reference to Fig. 30 and Fig. 31. In the sixth embodiment, only differences from the first embodiment are explained. In the sixth embodiment, components identical or similar to those of the first embodiment are denoted by the same reference numerals to omit unnecessary explanation.

[0207] The wireless positioning system 1 of the sixth embodiment differs from that of the first embodiment in that there are changes in the processing steps performed by the reference station 2 and in the position estimation processing steps. The remaining steps are similar to those of the first embodiment.

[0208] Upon receiving the information indicating the current location of the vehicle (vehicle current location information) from the vehicle-mounted device 3, the reference station 2 performs a step of incorporating the received current location information into a radio beacon.

[0209] Except for this additional step, the remaining steps are similar to those of the first embodiment. In other words, station 2 periodically transmits the radio beacon containing the identification information of reference station 2 and the received current vehicle location information to the surrounding vehicles using the direct wireless communication function.

[0210] As in Fig. 30, the position estimation processing of the sixth embodiment is similar to that of the first embodiment except that steps S1310 and S1320 are added.

[0211] Specifically, when step S100 is completed, control proceeds to step S1210. At step S1310, the CPU of the in-vehicle device 3 refers to the current vehicle location information included in the beacon acquired at step S40 and the current location of the host vehicle calculated at step S100 to calculate an inter-vehicle distance between the vehicle corresponding to the current vehicle location information and the host vehicle.

[0212] Then, at step S1320, the CPU 21 transmits information indicating the current location of the own vehicle (own vehicle current location information) calculated at step S100 to the reference station 2, and then once terminates the position estimation processing.

[0213] According to Fig. 31, a specific example of the inter-vehicle distance estimation performed in the wireless positioning system 1 configured as explained above will be explained below.

[0214] As in Fig. 31, a vehicle having the on-vehicle device 3a installed (hereinafter referred to as a first vehicle) and a vehicle having the on-vehicle device 3b installed (hereinafter referred to as a second vehicle) travel on a road R6 in the vicinity of the reference station 2a.

[0215] The first vehicle is traveling in front of the second vehicle. Furthermore, the first vehicle is traveling on a curve on road R6, while the second vehicle is traveling immediately before the curve. There is an obstacle on a line connecting the first and second vehicles (see dashed line DL61). In this case, if the second vehicle has a radar device installed, it is difficult for the second vehicle to accurately estimate the distance between the first vehicle and the second vehicle (inter-vehicle distance).

[0216] In this situation, however, the first vehicle can transmit its information about the current location of its own vehicle to the reference station 2a (see arrow AL61), and the reference station 2a can transmit the information about the current location of the first vehicle's own vehicle to the second vehicle (see arrow AL62). Thus, the second vehicle can accurately estimate the distance between the first vehicle and the second vehicle.

[0217] Furthermore, the second vehicle can transmit its information about a current location of its own vehicle to the reference station 2a (see arrow AL63), and the reference station 2a can transmit the information about a current location of the second vehicle's own vehicle to the first vehicle (see arrow AL64). Thus, the first vehicle can accurately estimate the distance between the first vehicle and the second vehicle.

[0218] The in-vehicle device 3 configured as described above transmits the current location information of a self-vehicle to the reference station 2 using the direct wireless communication device 13. The reference station 2 has a function of receiving the current location information of a self-vehicle through direct wireless communication and a function of transmitting the current location information of a self-vehicle through direct wireless communication (step S1320). Thus, the in-vehicle device can transmit / receive current location information of a self-vehicle to the reference station through direct wireless communication.

[0219] Accordingly, the vehicle-mounted device can determine an inter-vehicle distance to another vehicle-mounted device positioned in the vicinity of the same reference station 2.

[0220] In the embodiment described above, step S1320 is the position information transmission means or unit. Similarly, the current location information of a subject vehicle is the current location information of a device. (Seventh embodiment)

[0221] Next, a seventh embodiment of the present invention will be described with reference to Fig. 33, focusing on the differences from the third embodiment. In the seventh embodiment, components identical or similar to those of the third embodiment are denoted by the same reference numerals to omit unnecessary explanation.

[0222] As in Fig. As shown in Fig. 32, the wireless positioning system 101 of the seventh embodiment differs from the third embodiment in that the reference station 102 is set along an eight-lane road (four lanes in each direction) R7, an obstacle 150 is provided between the reference station 102 and the road R7, and the position estimation processing is changed. The remaining configuration is the same as that of the third embodiment.

[0223] Due to the presence of the obstacle 150 between the reference station 102 and the road R7, a direct wave arrival region A1, a diffraction wave arrival region A2 and a blocked region A3 are formed above the road R7.

[0224] The direct wave arrival region A1 (hereinafter also referred to as region A1) is a region for the arrival of direct waves not blocked by the obstacle 150 among the radio beacons transmitted from the reference station 102. The reference station 102 transmits the radio beacons using radio waves.

[0225] The diffracted wave arrival region A2 (hereinafter also referred to as region A2) is a region for the arrival of diffracted waves diffracted by the obstacle 150 among the radio beacons transmitted from the reference station 102.

[0226] The blocked region A3 (hereinafter also referred to as region A3) is a region where neither the direct waves nor the diffracted waves arrive.

[0227] The diffraction wave arrival region A2 is formed on both sides of the blocked region A3 along the travel direction of the road R7. With respect to the region A2 formed on either side of the blocked region A3, the direct wave arrival region A1 is formed on the other side of the region A2, which is opposite to the side where the blocked region A3 is formed.

[0228] The RAM 123 of the control unit 112 (compare Fig. 11) stores reference trajectory information regarding the reference station 102 that the control unit 112 has installed, which is classified based on the vehicle type and the direction of travel of the vehicles. Each piece of reference trajectory information includes reference trajectories regarding first to fourth lanes that configure the four lanes in one direction (compare reference trajectories TR1, TR2, TR3, and TR4 in Fig. 32).

[0229] The reference trajectory TR1 (TR2, TR3 or TR4) indicates that the test quantity gradually increases as the vehicle traveling on the first (second, third or fourth) lane of the road R7 approaches the reference station 2. Then, at the boundary between the region A1 and the region A2 on the first (second, third or fourth) lane, the reference trajectory TR1 bends in a direction of decreasing test quantity as the vehicle approaches the reference station 2 (compare the bending point Pa1 (Pa2, Pa3 or Pa4) in Fig. 32).

[0230] Furthermore, the reference trajectory TR1 (TR2, TR3, or TR4) indicates that as the vehicle moves away from the boundary region between regions A1 and A2 in the direction of the reference station, the test quantity gradually decreases. Furthermore, the reference trajectory TR1 bends at the boundary between regions A2 and A3 on the first (second, third, or fourth) lane (bending point Pb1 (Pb2, Pb3, or Pb4) in Fig. 32) and then states that the test quantity in region A3 is fixed.

[0231] The position estimation processing of the seventh embodiment is the same as that of the third embodiment except that step S370 has been changed.

[0232] In particular, step S370 differs from that of the third embodiment in that the CPU of the in-vehicle device 103 determines whether or not a test trajectory agrees with a reference trajectory.

[0233] In particular, the CPU 141 sets preferred and normal ranges for adjustment in each of the reference tracks TR1, TR2, TR3 and TR4 ( Fig. 32 shows preferred and normal adjustment ranges in the reference trajectory TR1. The preferred range is set to be specific to each of the reference trajectories TR1, TR2, TR3, and TR4. In this case, the preferred adjustment range for each of the reference trajectories TR1, TR2, TR3, and TR4 is set to include all of the regions A2 and A3. The normal adjustment range is also set to be specific to each of the reference trajectories TR1, TR2, TR3, and TR4. In each of the reference trajectories TR1, TR2, TR3, and TR4, the normal adjustment range corresponds to the range other than the preferred adjustment range.

[0234] Then, the test trajectory is superimposed on the reference trajectory, followed by calculating a difference between the test quantity of the reference trajectory and that of the test trajectory at several points on the reference trajectory (hereinafter, the difference is referred to as the test quantity difference). Further, the CPU 141 calculates an inverse value for each of the calculated test quantity differences, followed by multiplying the inverse value by a predetermined weighting coefficient.

[0235] Then, the CPU 141 calculates an average of the multiplied values ​​at the multiple points on the reference trajectory to use the average as a matching degree. Regarding the weighting coefficient in the preferential matching range, it is ensured to be larger than that of the normal matching range.

[0236] The wireless positioning system 101 configured as described above includes the obstacle 150 between the reference station 102 and the road R7 that surrounds the reference station 102. In this case, the obstacle 150 blocks the radio waves propagating from the reference station for transmitting the radio beacons.

[0237] Accordingly, the reference trajectory TR1 (TR2, TR3 and TR4) indicates that the test quantity gradually increases as the vehicle traveling on the first (second, third or fourth) lane of the road R7 approaches the reference station 2. Then, at the boundary between the region A1 and the region A2 on the first (second, third or fourth) lane, the reference trajectory TR1 bends in a direction of decreasing test quantity as the vehicle approaches the reference station 2 (compare bending point Pa1 (Pa2, Pa3 or Pa4) in Fig. 32). The bending point Pa1, Pa2, Pa3 or Pa4 is created at the boundary between regions A1 and A2.

[0238] The positions on road R7 corresponding to the bending points Pa1, Pa2, Pa3, and Pa4 of the correspondingly assigned reference trajectories TR1, TR2, TR3, and TR4 are unlikely to be affected by environmental reflection (i.e., reflection of radio waves from the buildings surrounding reference station 102) and are thus stable. Specifically, the bending point Pa1, Pa2, Pa3, or Pa4 will exhibit only a small variation in position in the vehicle's direction of travel on road R7 and the direction perpendicular to the direction of travel (i.e., in the direction from the first lane to the fourth lane). Likewise, the bending point Pa1, Pa2, Pa3, or Pa4 will exhibit only a small variation due to the different vehicle types.

[0239] This is because the test quantity of the direct waves becomes larger than the ambient reflection due to the fact that the reference station 102 is set up near the road R7 and because the bending points originate from the direct waves having such a large test quantity.

[0240] Thus, when bending points are generated in a generated test trajectory, the in-vehicle device 103 superimposes the bending points on the test trajectory on those generated on the reference trajectory TR1, TR2, TR3, or TR4 to accurately estimate the current location in the in-vehicle device 103 and the lane of the road R7 on which the vehicle having the in-vehicle device 103 installed (own vehicle) is traveling.

[0241] For example, the test track that is Fig. 32, coincides with the reference trajectory TR1 at the bending point Pa1. Accordingly, it is estimated that the vehicle having the on-vehicle device 103 installed is traveling on the first lane.

[0242] In the comparison between the reference trajectory information and the test trajectory information, the vehicle-mounted device 103 determines a relationship between the reference travel distance and the test travel distance by using the results of the comparison performed when the position on the road R7 in the reference trajectory information is included in the preferential area for matching, preferentially to the results of the comparison performed when the position is not included in the preferential area for matching (step S370).

[0243] As a result, the estimation of the current location of the in-vehicle device 103 and the lane is hardly affected by the comparison results performed in the normal matching range, which has lower estimation accuracy for these data than the preferential range. Thus, the estimation accuracy of the current location of the in-vehicle device 103 and the lane is maintained.

[0244] Furthermore, since the reference station 102 transmits the beacon using radio waves, the vehicle-mounted device is unlikely to be affected by weather when detecting the test quantity of the beacon.

[0245] Likewise, the vehicle-mounted device 103 calculates inverse values ​​of the test quantity differences at a plurality of points of the reference trajectory TR1, TR2, TR3, or TR4 as parameters indicating a degree of agreement between the test quantities of the reference trajectory TR1, TR2, TR3, or TR4 and the test quantities of the test trajectory.

[0246] At the same time, the vehicle-mounted device 103 multiplies each of the inverses of the test quantity differences calculated at the plurality of points on the reference trajectory TR1, TR2, TR3, or TR4 by a weighting coefficient predetermined based on the corresponding point on the reference trajectory.

[0247] Then, the vehicle-mounted device 103 determines the relationship between the reference travel distance and the test travel distance using the plurality of multiplied values.

[0248] Furthermore, it is ensured that the weighting coefficient in the case where the points of the reference career TR1, TR2, TR3 or TR4 are included in the preferential range for adjustment is greater than the weighting coefficients in the case where the points are not included in the preferential range for adjustment.

[0249] Thus, with a simple method in which the weighting coefficient between the preferential area for matching and areas other than the preferential area for matching is changed, the comparison results in the case where the points are included in the preferential area for matching can be used preferentially over the comparison results in the case where the points are not included in the preferential area for matching.

[0250] In the embodiment described above, the diffracted wave arrival region A2 and the blocked region A3 are the direct wave non-arrival region of the present invention. Similarly, the preferred range for matching is the preferred range; the inverse of a test quantity difference is the parameter indicating the degree of matching.

[0251] Various embodiments of the present invention have been explained. However, the present invention is not limited to these embodiments, but can be modified in various ways as long as the modifications remain within the technical scope of the present invention.

[0252] For example, in the above embodiments, the received signal strength (RSSI) is used as a test quantity. Alternatively, TOF (time of flight) or an angle of arrival of a radio wave can be used as a test quantity.

[0253] In the above embodiments, reference trajectory information is provided for each vehicle type. Alternatively, reference trajectory information may be provided for each type of direct wireless communication device installed in the vehicle-mounted device.

[0254] In the above embodiments, a reference trajectory is updated by determining whether the test trajectory is from the first lane or the second lane based on the speed information and the steering angle information. Alternatively, if the test trajectory statistics converge on multiple trajectories, the converged trajectories can be entered as the reference trajectories of the corresponding lanes.

[0255] In the above embodiments, a mean of test trajectories is calculated for the test trajectories of each classification, and the mean is used as a reference trajectory. Alternatively, a reference trajectory may be derived as a trajectory that maximizes the statistical indicator of a degree of similarity with respect to a group of test trajectories received in the past.

[0256] In the seventh embodiment, the obstacle 150 is provided between the reference station 102 and the road R7. However, as shown in Fig. 33, inside (for example, an indoor parking area) where a structure such as reinforced concrete or reinforced concrete with high marking properties is constructed, the reference station 102 can be provided so that the structure (the post 160 in Fig. 33) is located between the reference station 102 and a region in which positioning is carried out.

[0257] In the interiors, which cause many reflections, the received signal strength RSSI is strongly influenced by the surrounding vehicles, which causes large variation of a test trajectory (compare the arrow AR71 in Fig. 33). However, if a region for blocking direct waves is provided in a region where attenuation of the direct waves from the reference station 102 is small (a region close to the reference station 102), the characteristic points (compare bending points Pc1 and Pc2 in Fig. 33) with a higher contrast than the environmental factors are extracted.

[0258] In the seventh embodiment, the obstacle 150 is provided at a distance from the reference station 102. When either the reference station 102 or the obstacle 150 is used, the reference station 102 may be set up first, and then the obstacle 150 may be set up so that the obstacle 150 is located between the reference station 102 and the road. Alternatively, if the obstacle 150 is already set up near the road before the reference station 102 is set up, the reference station 102 may be set up so that the obstacle 150 is located between the reference station 102 and the road.

[0259] Furthermore, as in Fig. As shown in Figure 34, the obstacle 150 can be replaced by a blocking plate 170. The blocking plate 170 can be connected to the reference station 102 so that it is located between the reference station 102 and the road R7. Thus, the reference station 102 and the obstacle are integrated.

[0260] In this way, the positional relationship or spatial relationship between the reference station 102 and the obstacle is fixed, thereby suppressing variations in the positions of the bending points in the reference trajectory TR1, TR2, TR3, or TR4. Consequently, the accuracy of estimating the current location of the vehicle-mounted device 103 and the travel lane is improved.

[0261] In the seventh embodiment, beacons are transmitted using radio waves. Alternatively, beacons can be transmitted using optical waves. Since optical waves have a higher degree of directionality than radio waves, the influence of ambient reflections can be further reduced. However, optical waves are likely to be affected by weather. To minimize the influence of weather, beacons can be transmitted using sound waves.

[0262] In the seventh embodiment, the reference trajectories TR1, TR2, TR3, and TR4 are superimposed on a test trajectory to determine which of the reference trajectories TR1, TR2, TR3, and TR4 matches the test trajectory. Alternatively, a path traveled by the vehicle between lanes can be estimated based on the reference trajectories TR1, TR2, TR3, and TR4.

[0263] For example, as in Fig. 35, a vehicle having the vehicle-mounted device 103 installed can move from the fourth lane to the first lane (compare the arrow AR81 in Fig. 35). In this case, since the bending point on the test track coincides with the bending point Pa4 of the reference track TR4, the position on the fourth lane of the vehicle that has the vehicle-mounted device 103 installed can be estimated. Then, by comparing the test quantity of the test track with the test quantities of the reference tracks TR1, TR2, TR3, and TR4, the movement path from the fourth to the first lane can be estimated.

[0264] In the seventh embodiment, it is ensured that the weighting coefficient is larger when the points on the reference trajectory TR1, TR2, TR3, or TR4 are included in the alignment preferential area than the weighting coefficient when the points are not included in the alignment preferential area. Alternatively, the weighting coefficient may be determined according to the distance between the alignment preferential area and the current location of the vehicle. For example, it may be ensured that the weighting coefficient becomes smaller as this distance increases.

[0265] In the seventh embodiment, a test track is compared with a reference track using the inverses of the test quantity differences. Alternatively, a test track can be compared with a reference track using the distance between two bending points generated in the test track and the distance between two bending points generated in the reference track (compare arrow AR91 in Fig. 32. The arrow AR91 indicates the distance between the two bending points Pa1 on the reference track TR1).

[0266] For example, in Fig. 32, the distance between the two bending points generated in the test track is equal to the distance between the two bending points Pa1 on the reference track TR1. Therefore, the vehicle having the on-vehicle device 103 installed can be estimated to be traveling on the first lane.

[0267] While the invention has been particularly shown and explained with reference to embodiments and modifications thereof, the invention is not limited to these embodiments and modifications. It will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the present invention as defined in the claims.

[0268] The invention can be summarized as follows. In a wireless communication device, data transmitted from at least one wireless transmitter is received by direct wireless communication, and its wireless reception state is detected. Relational reference information defining two or more relations between the wireless reception state for receiving transmitted data and location information is stored. Relative distance information of a relative distance between the transmitter and the device is measured. Relational information indicating a relationship between the wireless reception conditions and the relative distance information is generated. A relationship between the location information and the relative distance information is determined by comparing the relational reference information and the relational information.A current location of the device is determined based on the relationship between the location information and the relative distance information and a current wireless reception state.

Claims

[1] Wireless communication device (3, 103, 203), comprising: a wireless communication means (13, 133, 213) for receiving data transmitted by at least one wireless transmitter (2, 102, 203) through direct wireless communication, wherein the at least one wireless transmitter (2, 102, 203) transmits data in a wireless manner; a detecting means (21(S50), 22, 141(S340), 142, 221(S1050), 222) for detecting a wireless reception state in the wireless communication means; reference information storage means (23, 143, 223) for storing relational reference information specifying two or more relations between (i) the wireless reception state in the wireless communication means for receiving data transmitted from the wireless transmitter and (ii) location information regarding a location of the wireless transmitter; a distance measuring means (21(S60), 22, 141(S360), 142, 221(S1070), 222) for measuring relative distance information regarding a relative distance between the wireless transmitter and the wireless communication device; a first generating means (21(S70), 22, 141(S360), 142, 221(S1070), 222) for generating first relation information indicating a relationship between a plurality of the wireless reception states detected by the detecting means and a plurality of the relative distance information measured by the distance measuring means; a relation determining means (21(S80), 22, 141(S370), 142, 221(S1100), 222) for determining a relation between the location information and the relative distance information by comparing the relation reference information and the first relation information; and a position determining means (21(S90, S100), 22, 141(S380, S390), 142, 221(S1110), 222) for determining a current location of the wireless communication device based on (a) the relation between the location information and the relative distance information determined by the relation determining means, and (b) a current wireless reception state in the wireless communication means detected by the detecting means. [2] Wireless communication device according to claim 1, characterized by , that: the wireless transmitter (2, 102) is provided to be fixed to a predetermined installation position; the location information in the relational reference information is information indicating a position on a road surrounding the wireless transmitter; and the relative distance information in the first relational information is a travel distance of a vehicle equipped with the wireless communication device and traveling on the road surrounding the wireless transmitter. [3] Wireless communication device according to claim 2, characterized by , that: the relation reference information is set for each type of vehicle. [4] Wireless communication device according to claim 2 or 3, characterized by , that: the road has multiple lanes in each direction; and the relation reference information is set for each lane of the road. [5] Wireless communication device according to one of claims 1 to 4, further characterized by : a first reference information obtaining means (141(S320, S330, S410, S420), 142) for obtaining the relation reference information transmitted from the wireless transmitter by using the wireless communication means. [6] Wireless communication device according to claim 5, further characterized by : a first measurement information transmission means (141(S400), 142) for transmitting the first relation information generated in the first generation means to the wireless transmitter using the wireless communication means. [7] Wireless communication device according to one of claims 1 to 6, further characterized by : a second reference information acquiring means (21(S30), 22) for acquiring the relation reference information transmitted from a first management device (4) provided for each wireless transmitter to manage the relation reference information by performing wireless communication with the first management device via a wireless wide area communication network. [8] Wireless communication device according to claim 7, further characterized by : a second measurement information transmission means (21(S20), 22) for transmitting the first relation information generated in the first generation means to the first management device by performing wireless communication by means of the wireless wide area communication network. [9] Wireless communication device according to claim 8, further characterized by : a movement trajectory transmission means (21(S900), 22) for transmitting movement trajectory information indicating a movement trajectory of the wireless communication device to the first management device by performing wireless communication by means of the wireless wide area communication network. [10] Wireless communication device according to one of claims 1 to 9, characterized by , that: the wireless transmitter includes a receiving function for receiving current location information indicating a current location of the wireless communication device by direct wireless communication and a transmitting function for transmitting the received current location information by direct wireless communication; and the wireless communication device further comprises location information transmitting means (21(S1320), 22) for transmitting the current location information to the wireless transmitter. [11] Wireless communication device according to claim 1, characterized by , that: the wireless transmitter (203) is mounted in a first moving object moving on a road; the location information in the relational reference information is information indicating a relative distance between the first moving object and the wireless communication device; and the relative distance information around the first relational reference information is information indicating an increase and a decrease of a relative distance between the first moving object and the wireless communication device with respect to a relative reference distance, which is a relative distance between the first moving object and the wireless communication device at a predetermined time. [12] Wireless communication device according to claim 11, further characterized by : a third reference information obtaining means (221(S1030), 222) for obtaining the relation reference information transmitted from a second management device (204) that manages the relation reference information by performing wireless communication with the second management device via a wireless wide area communication network. [13] Wireless communication device according to claim 12, characterized by, that: the wireless communication device is mounted in a second moving object moving on a road; the second moving object is equipped with a relative distance measuring device that measures a relative distance to the first moving object traveling in front of the second moving object; and the wireless communication device further comprises: a second generating means (221(S1090), 222) for generating a relation between the wireless reception state detected by the detecting means and information indicating the relative distance measured by the relative distance measuring means; and a third measurement information transmission means (221(S1020), 222) for transmitting the second relation information generated in the second generation means to the second management device by performing wireless communication by means of the wireless wide area communication network. [14] Wireless communication device according to one of claims 2 to 4, characterized by , that: an obstacle (150, 170) is arranged between the wireless transmitter and a road surrounding the wireless transmitter, the obstacle blocking a portion of waves propagating from the wireless transmitter to transmit data; and the relation determination means (141(S370), 142) is configured to determine the relation using a first comparison result preferentially to a second comparison result in a comparison between the first relation reference information and the relation information, the first comparison result is a result of the comparison carried out in a case where the location information in the relational reference information is included in a preferential area that is set in advance to include a boundary between a direct wave arrival region and a direct wave non-arrival region, wherein the direct wave arrival region is a region on the road at which direct waves arrive and the direct wave non-arrival region is a region on the road at which the direct waves do not arrive and the direct waves are the waves that arrive at the road from the wireless transmitter without being blocked by the obstacle, and the second comparison result is a result of the comparison performed in a case where the location information in the relation reference information is not included in the preferential area. [15] Wireless communication device according to claim 14, characterized by , that: the obstacle (170) is intended to be attached to the wireless transmitter. [16] Wireless communication device according to claim 14 or 15, characterized by , that: the waves are radio waves. [17] Wireless communication device according to claim 14 or 15, characterized by , that: the waves are light waves. [18] Wireless communication device according to claim 14 or 15, characterized by , that: the waves are sound waves. [19] Wireless communication device according to one of claims 14 to 18, characterized by , that: the relation determination means is configured to: calculate a parameter indicating a degree of correspondence between the wireless reception state in the relational reference information and the wireless reception state in the first relational information at a plurality of calculation positions indicated by the location information in the relational reference information, calculate a multiplied value by multiplying the parameter calculated for each calculation position by a weighting coefficient predetermined based on the corresponding calculation position and set such that a first weighting coefficient is greater than a second weighting coefficient, wherein the first weighting coefficient is a weighting coefficient in a case where the calculation position is included in the preferential range for matching, and the second weighting coefficient is a weighting coefficient in a case where the calculation position is not included in the preferential range for matching; and to determine the relation using the calculated multiplied value. [20] Wireless positioning system (1, 101, 201), comprising: the at least one wireless transmitter (2, 102, 203) according to claim 1; and the wireless communication device (3, 103, 203) according to claim 1.

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