Map providing server and map providing method

Abstract

The emergency braking area is estimated from the vehicle's position information. [Solution] A map providing server that estimates potential locations for sudden braking by acquiring vehicle information including the time progression of position information measured at predetermined time intervals from positioning sensors mounted on each of multiple vehicles traveling on a road or on portable terminals used by users in each vehicle, as well as vehicle speed information at the same time, and then calculates sudden braking areas by performing clustering processing on the potential locations for sudden braking and plots them on a road map.

Description

[Technical Field]

[0001] The present invention relates to a map providing server and a map providing method that estimates locations where sudden braking occurs based on vehicle position data measured at predetermined time intervals of at least 10 seconds and plots the locations on a road map. [Background technology]

[0002] For the purpose of preventing traffic accidents, technologies have been developed to share information on so-called "near misses" and alert users. For example, Patent Document 1 discloses a technology that acts as a map providing server that acquires driving information, including the occurrence and location of sudden braking, from multiple vehicles, plots locations where sudden braking frequently occurs on a map, and associates the locations with the dangerous locations that have been plotted, enabling users to post such information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5805128 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in the patent document, in order to identify locations where sudden braking frequently occurs, it is necessary to acquire information about the occurrence of sudden braking from the vehicle. To do this, for example, it is necessary to provide a sensor such as an acceleration sensor in the vehicle and mount a smartphone on it, but providing a sensor in the vehicle is not practical in the case of, for example, an inexpensive motorcycle, because it leads to an increase in the selling price. Even when a smartphone is installed, the user's consent is required within the application to acquire the data, and since it is not data from which the user can directly benefit, obtaining consent is difficult. Application providers also have a need to minimize the amount of data they acquire due to management issues. For this reason, it is desirable to identify locations where sudden braking frequently occurs using position data without acquiring data from an acceleration sensor.

[0005] The present invention aims to provide a map providing server and a map providing method that can estimate locations where sudden braking frequently occurs and plot the locations on a map by acquiring vehicle information including time transitions of vehicle position information measured at predetermined time intervals of at least 10 seconds from positioning sensors (for example, positioning sensor 24 described below) mounted on multiple vehicles traveling on a road or mobile devices paired with the vehicles. This makes it possible to estimate locations on a road where sudden braking frequently occurs with a simple configuration that utilizes measurement information from positioning sensors mounted on many vehicles. [Means for solving the problem]

[0006] (1) A map providing server of the present invention (for example, a map providing server 30 described later) includes a vehicle information receiving unit (for example, a vehicle information receiving unit 311 described later) that receives vehicle information including a time transition of position information at a predetermined time interval of at least 10 seconds from a positioning sensor (for example, a positioning sensor 24 described later) mounted on a plurality of vehicles (for example, a vehicle 50 described later) traveling on a road; a map unit (for example, a map information storage unit 322 described later) that stores road map information; a location selecting unit (for example, a location selecting unit 312 described later) that selects, from the vehicle information, for specific second position information among the position information, first position information that was recorded a predetermined time before the second position information and third position information that is a position after the predetermined time of the second position information; speed information at the time of acquisition of the first position information; The system is equipped with an estimation unit (e.g., a candidate sudden braking location estimation unit 313 described later) that calculates an average speed of the vehicle from speed information at the time the second position information was acquired, or a combination of speed information at the time the second position information was acquired and speed information at the time the third position information was acquired, calculates an estimated location after the predetermined time from the average speed and the second position information as estimated location information, and estimates a point of the second position information where the deviation rate between the third position information and the estimated location information is equal to or greater than a predetermined value as a candidate sudden braking location, and a clustering processing unit (e.g., a clustering processing unit 314 described later) that calculates a sudden braking area by clustering the candidate sudden braking locations estimated for each of the plurality of vehicles and plots the area on the road map.

[0007] According to (1) above, it is possible to estimate road locations where sudden braking frequently occurs with a simple configuration that acquires measurement information (position data) from positioning sensors equipped on many vehicles at predetermined time intervals of at least 10 seconds. Therefore, it is applicable to, for example, a plurality of vehicles, particularly inexpensive motorcycles, and by reducing the amount of data transmitted, it is possible to solve management problems and reduce communication costs related to the transmission.

[0008] (2) In the map providing server (e.g., the map providing server 30 described later) described in (1) above, the clustering processing unit (e.g., the clustering processing unit 314 described later) may use the DBSCAN method as a clustering processing method, which performs clustering based on data density, and the sudden braking area may be an area formed by the clustering processing.

[0009] According to (2) above, by clustering position data acquired from many vehicles at predetermined time intervals using DBSCAN, noise can be removed, making it possible to accurately estimate candidate locations where sudden braking occurs frequently.

[0010] (3) In the map providing server (e.g., the map providing server 30 described later) described in (1) or (2) above, the estimation unit (e.g., the candidate sudden braking location estimation unit 313 described later) may use a deviation rate defined by a value obtained by dividing the difference between the distance between the second position information and the estimated position information and the distance between the second position information and the third position information by the average speed.

[0011] According to (3) above, by calculating the deviation rate between two points based on position data and speed information acquired from many vehicles in chronological order at predetermined time intervals, it is possible to accurately estimate points where sudden braking occurs frequently.

[0012] (4) In the map providing server (e.g., the map providing server 30 described later) described in (1) or (2) above, the estimation unit (e.g., the candidate sudden braking location estimation unit 313 described later) may use a deviation rate defined by a value obtained by dividing the difference between the distance between the second position information and the estimated position information and the distance between the second position information and the third position information by the distance between the second position information and the estimated position information.

[0013] According to (4) above, by calculating the deviation rate between two points based on position data and speed information acquired from many vehicles in chronological order at predetermined time intervals, it is possible to accurately estimate candidate points where sudden braking occurs frequently.

[0014] (5) The map providing method of the present invention comprises: A map providing method executed by one or more computers equipped with road map information, the method comprising: a vehicle information receiving step of receiving vehicle information including a time transition of position information at a predetermined time interval of at least 10 seconds from positioning sensors mounted on a plurality of vehicles traveling on a road; a position selecting step of selecting, from the vehicle information, for specific second position information among the position information, first position information recorded before the predetermined time of the second position information and third position information which is a position after the predetermined time of the second position information; and a step of selecting speed information at the time of acquiring the first position information, speed information at the time of acquiring the second position information, or third position information. The method includes an estimation step of calculating an average speed of the vehicle from a combination of either the speed information at the time the second position information is acquired or the speed information at the time the third position information is acquired, calculating an estimated position after the predetermined time from the average speed and the second position information as estimated position information, and estimating a point of the second position information where the deviation rate between the third position information and the estimated position information is equal to or greater than a predetermined value as a candidate sudden braking location, and a clustering processing step of calculating a sudden braking area by clustering the candidate sudden braking locations estimated for each of the plurality of vehicles and plotting the area on the road map.

[0015] According to the method (5) above, the same effect as the map providing server of (1) above can be achieved. [Effects of the Invention]

[0016] According to the present invention, it is possible to estimate road locations where sudden braking frequently occurs with a simple configuration that acquires measurement information (position data) from positioning sensors equipped on many vehicles at predetermined time intervals of at least 10 seconds. Therefore, it can be applied to, for example, multiple vehicles, particularly inexpensive motorcycles, and by reducing the amount of data transmitted, it is possible to solve management problems and reduce communication costs related to the transmission, and by plotting the data on a map, it is possible to alert many users. Therefore, it contributes to improving the environment and living standards, "making cities and human settlements inclusive, safe, resilient and sustainable," and is well suited to achieving the SDG 11, which aims to ensure safe and sustainable transportation. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing a basic configuration of an entire map providing system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a functional block diagram showing the functional configuration of a mobile terminal according to an embodiment of the present invention. [Figure 3] FIG. 2 is a functional block diagram showing the functional configuration of a map providing server according to the embodiment of the present invention. [Figure 4] 3 is a table illustrating an example of a vehicle position information table according to an embodiment of the present invention. [Figure 5] FIG. 4 is a diagram showing an example of a travel distance when sudden braking occurs and a travel distance when sudden braking does not occur in the embodiment of the present invention. [Figure 6] FIG. 1 is a diagram illustrating an example of three types of data points handled by DBSCAN used in an embodiment of the present invention. [Figure 7] 10A and 10B are diagrams illustrating an example of clusters and noise not assigned to clusters according to an embodiment of the present invention. [Figure 8] 4 is a flowchart showing a basic operation of the map providing server according to the embodiment of the present invention. [Figure 9] FIG. 1 is an image diagram in which a plurality of clusters are plotted on a map according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] A preferred embodiment of the map providing system 1 of the present invention will be described in detail below with reference to the drawings.

[0019] <Overall configuration of map provision system 1> A map providing system 1 according to a preferred embodiment of the present invention will be described below. FIG.

[0020] 1, the map providing system 1 includes a map providing server 30, a vehicle 50, and an in-vehicle device 10 or a mobile terminal 20. In this embodiment, the mobile terminal 20 is assumed to be a motorcycle, and the vehicle 50 is assumed to be a motorcycle, but the in-vehicle device 10 can be used in place of the mobile terminal 20, and the motorcycle can be used in place of a regular four-wheeled vehicle. The map providing server 30 and the mobile terminal 20 used by the user in the vehicle 50 are connected to each other via a communication network 60 so that they can communicate with each other. Although the diagram also illustrates information exchanged between the map providing server 30 and each mobile terminal 20, this information is merely an example. In this embodiment, information other than that illustrated may be exchanged. In this embodiment, a case will be described in which vehicle information is transmitted from the mobile terminal 20 to the map providing server 30, but the mobile terminal 20 may be read as the in-vehicle device 10.

[0021] The mobile terminal 20 is a mobile terminal used by a user who is in the vehicle 50. The mobile terminal 20 has a function of measuring the position information of the mobile terminal 20 (that is, the position information of the vehicle 50).

[0022] The mobile terminal 20 appropriately transmits to the map providing server 30, location information measured at predetermined time intervals of at least 10 seconds or more, linked to a mobile object ID, which is identification information for identifying the mobile terminal 20. Here, the mobile terminal 20 and the vehicle 50 are used as a one-to-one pair, so the transmitted location information can be essentially regarded as location information of the vehicle 50. Furthermore, the mobile terminal 20 measures location information at predetermined time intervals, and also acquires speed information of the vehicle 50 at that time and transmits it to the map providing server 30. As the mobile ID, for example, a telephone number assigned to a SIM (Subscriber Identity Module) inserted into the communication unit 13 can be used so that the communication unit 13 can connect to the communication network 60, which is a network such as a mobile phone network. In addition, a VIN (Vehicle Identification Number) or a license plate number assigned uniquely to the vehicle 50 can also be used. In this way, the map providing server 30 can acquire, for each mobile object ID, vehicle information including time information (time stamps) at which the position of the vehicle 50 is measured at predetermined time intervals, vehicle position information, and speed information of the vehicle at that time. In the following description, the vehicle 50 and the mobile terminal 20 are also referred to as "mobile objects" as appropriate. Such a mobile terminal 20 can be realized by a smartphone, a mobile phone, a tablet terminal, a notebook computer, or other portable electronic device.

[0023] The map providing server 30 is a device that acquires vehicle information including the time progression of position information measured at predetermined time intervals from a positioning sensor 24 mounted on each vehicle traveling on the road or on a portable terminal carried by a user in each vehicle, and vehicle speed information at the same time, to estimate locations where sudden braking frequently occurs and plot the locations on a map.

[0024] The vehicle 50 is a moving body that is ridden by a user of the mobile terminal 20. In this embodiment, the vehicle 50 is realized by a motorcycle or the like.

[0025] The communication network 60 is realized by a network such as the Internet or a mobile phone network, or a network that combines these. Before describing the map providing server 30, a brief description of the mobile terminal 20 will be given.

[0026] <Regarding the mobile terminal 20> As shown in FIG. 2, the mobile terminal 20 includes a control unit 21, a storage unit 22, a communication unit 23, a positioning sensor 24, a display unit 25, an input unit 26, and a short-range communication unit 27.

[0027] The control unit 21 is configured with a processing unit such as a microprocessor, and controls each unit that configures the mobile terminal 20.

[0028] The memory unit 22 is composed of semiconductor memory or the like, and stores various programs such as control programs called firmware and operating systems, a program for transmitting vehicle information including the position information of the vehicle 50 measured at predetermined time intervals and the time-varying changes in the vehicle's speed information to the map providing server 30, and other various information such as map information.

[0029] The figure illustrates vehicle information 221, which includes position information of the vehicle 50 measured at predetermined time intervals, time information when the positioning was performed, and speed information of the vehicle 50 at that time, as information stored in the storage unit 22. The predetermined time interval may be at least 10 seconds or more, for example, 30 seconds. As described above, the moving body ID is information for identifying the vehicle 50. The position information is the position information (latitude and longitude information) of the mobile terminal 20 (vehicle 50) measured by the positioning sensor 24, and the position information 121 includes not only information indicating the measured position but also the time when the positioning was performed. The speed information is, for example, information about the speed of the vehicle 50 at the time when the positioning is performed, which is acquired from the ECU of the vehicle 50.

[0030] The communication unit 23 includes a DSP (Digital Signal Processor) and implements wireless communication with the map providing server 30 via the communication network 60 in accordance with standards such as LTE (Long Term Evolution), 4G (4th Generation), 5G (5th Generation), or Wi-Fi (registered trademark). The communication unit 23 is used to transmit vehicle information stored in the storage unit 22 and acquired at predetermined time intervals of at least 10 seconds to the map providing server 30. In this way, the communication unit 23 transmits vehicle information at predetermined time intervals, thereby significantly reducing communication costs. Furthermore, the amount of data requiring user consent can be reduced.

[0031] The positioning sensor 24 is configured by, for example, a GPS (Global Positioning System) sensor. The positioning sensor 24 has a function as a position detection means for detecting position information, and receives GPS satellite signals using the GPS sensor to measure the position information (latitude and longitude) of the mobile terminal 20. The positioning sensor 24 measures the position at predetermined time intervals (for example, every 30 seconds) as described above. The measured position information is stored in the storage unit 22 as vehicle information 221. The display unit 25 is configured by a display device such as a liquid crystal display or an organic electroluminescence panel, etc. The display unit 25 receives an instruction from the control unit 21 and displays an image. The input unit 26 is configured with an input device (not shown) such as a physical switch called a numeric keypad or a touch panel provided over the display surface of the display unit 25.

[0032] On the other hand, the mobile terminal 20 includes a short-range communication unit 27. Here, the short-range communication unit 27 is a unit for performing contactless short-range communication conforming to standards such as NFC (Near Field Communication) and Bluetooth (registered trademark), or wired short-range communication via a USB (Universal Serial Bus) cable or the like.

[0033] On the other hand, although not shown, the vehicle 50 includes a short-range communication unit for communicating with the short-range communication unit 27. For example, an ECU (Electronic Control Unit) of the vehicle 50 includes the short-range communication unit. The mobile terminal 20 can communicate with the ECU via short-range communication when, for example, the mobile terminal 20 is present inside the vehicle 50. In the case of a motorcycle, the mobile terminal 20 can be loaded in the cockpit of the motorcycle or carried by the driver. The position information measured by the positioning sensor 24 of the mobile terminal 20 corresponds to the position information of the vehicle 50.

[0034] Therefore, the mobile terminal 20 may activate the vehicle information transmission unit 211 while short-range communication with the vehicle's ECU is possible via, for example, the short-range communication unit 27. The activated vehicle information transmission unit 211 then transmits, to the map providing server 30, as vehicle information 221, the position information of the vehicle 50 measured by the positioning sensor 24 at predetermined time intervals, together with the moving object ID, time information (time stamp), and vehicle speed information at that time acquired from the vehicle's ECU.

[0035] For example, when a user gets into vehicle 50 carrying mobile terminal 20 and turns on the start switch of vehicle 50, such as an ignition switch, vehicle 50 and mobile terminal 20 are connected (paired), and thereafter, mobile terminal 20 paired with vehicle 50 links vehicle information 221, including vehicle speed information acquired from vehicle 50 at predetermined time intervals and latitude and longitude position information of mobile terminal 20 measured at predetermined time intervals (which is also position information of vehicle 50), to a mobile body ID and transmits the information to map providing server 30 each time. When the start switch of the vehicle 50, such as an ignition switch, is turned off, the pairing between the vehicle 50 and the mobile terminal 20 is released, and the acquisition of the vehicle information 221 and the transmission of the vehicle information 221 to the map providing server 30 are terminated. The mobile terminal 20 may collectively transmit a plurality of pieces of vehicle information obtained at predetermined time intervals to the map providing server 30, for example, within a predetermined time range.

[0036] In addition, if the vehicle 50 is equipped with an in-vehicle device 10 that has a function of measuring location information, the in-vehicle device 10 that has a configuration equivalent to that of the mobile terminal 20 may perform the same processing as the mobile terminal 20 described above.

[0037] <About the map providing server 30> Next, the functional blocks of the map providing server 30 will be described with reference to the block diagram of FIG.

[0038] As shown in FIG. 3, the map providing server 30 includes a control unit 31, a storage unit 32, and a communication unit 33.

[0039] The control unit 31 is configured with an arithmetic processing device such as a microprocessor, and controls each unit that configures the map providing server 30. Details of the control unit 31 will be described later.

[0040] The storage unit 32 is composed of a semiconductor memory or the like, and stores various programs such as control programs called firmware or operating systems, programs for performing emergency braking area calculation processing, map information, etc. Furthermore, the storage unit 32 stores the vehicle position information transmitted from the mobile terminal 20 as a vehicle position information table 321. Fig. 4 shows an example of the vehicle position information table 321 in the embodiment of the present invention.

[0041] As shown in FIG. 4, the vehicle position information table 321 stores, for each vehicle 50, time transition information including at least a "mobile body ID," "positioning time information" at predetermined time intervals, "vehicle position information at the positioning time (e.g., latitude and longitude information)," and "vehicle speed information at the positioning time." The "temporal transition" in the vehicle position information table 321 is the position information measured at predetermined time intervals received from the moving body from the start of transmission of position information, speed information, etc. until the end of transmission. The memory unit 32 may also include a map information memory unit 322 that includes, for example, information about roads, display map data for displaying the background of road maps, etc., position information and type information of nodes (e.g., road intersections, bends, end points, etc.), position information and type information of links that are routes connecting each node, and link cost data related to cost information of all links (e.g., distance, required time, etc.).

[0042] The communication unit 33 has a DSP and the like, and conforms to standards such as LTE (Long Term Evolution), 4G (4th Generation), 5G (5th Generation), or Wi-Fi (registered trademark), to realize wireless communication or wired communication with other devices (such as the mobile terminal 20) via the communication network 60. The communication unit 33 is used to receive vehicle information including a mobile object ID, time information, location information, speed information, etc., transmitted from the mobile terminal 20 or the in-vehicle device 10 at predetermined time intervals.

[0043] Next, the control unit 31 will be described in detail. The control unit 31 is configured by a microprocessor having a CPU, RAM, ROM, I / O, etc. The CPU executes each program read from the ROM or storage unit 32, and during execution, reads information from the RAM, ROM, and storage unit 32, writes information to the RAM and storage unit 32, and exchanges signals with the communication unit 33. In this way, the processing in this embodiment is realized by the cooperation of hardware and software (programs).

[0044] The control unit 31 includes, as functional blocks, a vehicle information receiving unit 311, a position selecting unit 312, a sudden braking candidate location estimating unit 313, and a clustering processing unit 314.

[0045] <Vehicle information receiving unit 311> The vehicle information receiving unit 311 receives, via the communication unit 33, the location information of the vehicle 50 measured by the positioning sensors 24 mounted on multiple moving bodies traveling on the road, as vehicle information from each moving body, along with the moving body ID of the vehicle 50, time information (time stamp), and speed information of the vehicle 50 at that time. The vehicle information receiving unit 311 creates a vehicle position information table 321 shown in Fig. 4, which is time transition data for each vehicle, based on the vehicle information received from the moving body and measured or acquired at predetermined time intervals. The vehicle information receiving unit 311 may also create the vehicle position information table 321 for a predetermined area and a predetermined period. This makes it possible to display, for example, near-miss information for that area.

[0046] <Position selection unit 312> For each vehicle, the location selection unit 312 selects, from the time progression information of the vehicle information of the vehicle, for specific second location information among the location information, first location information recorded a predetermined time before the second location information and third location information which is the location a predetermined time after the second location information. Specifically, the location selection unit 312 selects (creates) a set of first location information, second location information, and third location information as follows.

[0047] The position information of the vehicle 50 measured at predetermined time intervals along with the time transition Let P(i)(1≦i≦N) {where N is the total number of predetermined time intervals related to the vehicle}. The location selection unit 312 selects, from the location information of the vehicle over time, For each i where 1≦i≦N-2, the three adjacent position information are as follows: Select {P(i), P(i+1), P(i+2)}.

[0048] In the three adjacent position information {P(i), P(i+1), P(i+2)} selected by the position selection unit 312, P(i) is named the first position, P(i+1) is named the second position, and P(i+2) is named the third position.

[0049] If the speed information of the vehicle at the first position P(i), the second position P(i+1), and the third position P(i+2) selected by the position selection unit 312 are V(i), V(i+1), and V(i+2), respectively, the position selection unit 312 can select two adjacent speed information {V(i), V(i+1)} corresponding to two adjacent position information {P(i), P(i+1)}.

[0050] <Sudden braking candidate location estimation unit 313> The sudden braking candidate location estimation unit 313 calculates the average speed V'(i) of the vehicle from the first position P(i) to the second position P(i+1) from the speed information V(i) at the first position P(i) and the speed information V(i+1) at the second position P(i+1). V´(i) = (V(i)+V(i+1)) / 2 Next, assuming that the vehicle travels from the second position P(i+1) toward the third position P(i+2) at an average speed V'(i) over a predetermined time, the sudden braking candidate location estimation unit 313 can calculate the estimated position after the predetermined time from the second position P(i+1) as the estimated position P'(i+2).

[0051] FIG. 5 is a diagram showing an example of the travel distance when sudden braking occurs when traveling from the second position P(i+1) toward the third position P(i+2) and the travel distance when sudden braking does not occur. As shown in Figure 5, if a sudden braking incident occurs between the second position P(i+1) and the third position P(i+2), causing the vehicle to stop or drive slowly, then accelerate and reach the third position P(i+2) after a predetermined time, the difference between the travel distance Xact from the second position P(i+1) to the third position P(i+2) and the estimated distance Xest from the second position P(i+1) to the estimated position P'(i+2) obtained assuming smooth driving without the sudden braking incident occurring is Xest > Xact It is thought that this will occur. The sudden braking potential location estimation unit 313 can calculate a deviation rate in order to determine the deviation relatively. Deviation rate = (Xest - Xact) / Xest The sudden braking candidate location estimation unit 313 determines the second position P(i+1) as the sudden braking candidate location A(j) when the deviation rate exceeds or is equal to or greater than a preset threshold. In this way, the sudden braking potential location estimation unit 313 can calculate the sudden braking potential locations A(j) for all vehicles. As described above, the location information is latitude and longitude information, and the distance between two pieces of location information is calculated as, for example, the straight-line distance between the two latitudes and longitudes. The direction of the estimated location is also calculated as, for example, the direction from the second location to the third location.

[0052] In this way, the sudden braking location candidate estimation unit 313 selects the second position P(i+1) {1≦i≦N−2} for each vehicle 50, calculates estimated position information P′(i+2) for each selected second position information P(i+1), and calculates the deviation rate (i) based on the third position information P(i+2) and the estimated position information P′(i+2). For example, by doing so, the set of second positions P(i+1) calculated for each vehicle for which the deviation rate exceeds or is equal to or greater than a threshold value can be treated as a subset of the set of sudden braking location candidate locations. Then, by creating a union of the subsets of sudden braking location candidate locations calculated for each vehicle, a set of sudden braking location candidate locations in a predetermined area can be calculated.

[0053] In addition, when the sudden braking candidate location estimation unit 313 makes a sudden braking judgment, it is expected that a discrepancy between the actual travel distance Xact and the estimated distance Xest will occur even in cases other than sudden braking, for example, even in normal speed control, and therefore it is expected that the sudden braking candidate location set {A(j)} will contain such noise. Such noise can be dealt with by noise removal using clustering, as will be described later.

[0054] In addition, in the above example, the average speed V'(i) of the vehicle when traveling from the second position P(i+1) to the third position P(i+2) was the average speed of the vehicle from traveling at the first position P(i) to the second position P(i+1), but this is not limited to this. If speed information at each position can be obtained, the average speed V''(i) of the vehicle traveling from the second position P(i+1) to the third position P(i+2) may be used. V´´(i) = (V(i+1)+V(i+2)) / 2

[0055] In addition, in the above example, the deviation rate was calculated by dividing the difference between the distance between the second position information and the estimated position information and the distance between the second position information and the third position information by the distance between the second position information and the estimated position information. However, it is also possible to apply a divided value by dividing the difference between the distance between the second position information and the estimated position information and the distance between the second position information and the third position information by either the average speed of the vehicle from the first position to the second position or the average speed of the vehicle from the second position to the third position.

[0056] <Clustering processing unit 314> The clustering processing unit 314 performs clustering processing on the sudden braking candidate location set {A(j)} calculated by the sudden braking candidate location estimation unit 313 to calculate a sudden braking area. Specifically, the clustering processor 314 uses, for example, the DBSCAN (Density-Based Spatial Clustering) method, which performs clustering based on data density, as a clustering method. In this way, the hard braking area can be calculated as an area formed by the clustering process.

[0057] DBSCAN is a type of clustering technique in which two parameters (radius eps and minimum number of points that make up a cluster MinPts) are determined in advance, and points that fall within a circle drawn with that radius are considered to be in the same cluster and divided. Figure 6 shows an example of three types of data points handled by DBSCAN. Here, eps is set to 50m and MinPoints is set to 3. As shown in Figure 6, points are divided into Corepoints, which are points in the eps range that include data points equal to or greater than MinPts; Borderpoints, which are points in the eps range that are less than MinPts and include Corepoints; and Noisepoints, which are points in the eps range that are less than MinPts and do not include Corepoints. Borderpoints are assigned to the same cluster as the corepoints that are reachable from the corepoints by data points. Noisepoints are not assigned to any clusters as they are considered noise. For example, the two parameters may be set as eps = 50 m and MinPoints = 3. The two parameter values ​​(eps and MinPoints) may be changed as appropriate depending on the predetermined time interval for positioning, the final estimation result of the emergency braking area, etc.

[0058] For example, it is estimated that points (Core points and Border points) estimated as candidate locations for sudden braking by the candidate sudden braking location estimation unit 313 are concentrated at locations where sudden braking frequently occurs (near misses). For this reason, as shown in Fig. 7, it is expected that the accuracy of the area determined to be a near miss location will improve by removing, as noise, points (Noise points) that are far from the locations where near misses estimated by DBSCAN are concentrated. In this way, according to the present invention, it is possible to estimate the location of sudden braking using only position data obtained by measuring positions at predetermined time intervals (for example, 30 seconds). The configuration of each functional unit of the map providing server 30 exemplified as this embodiment has been described above.

[0059] The above describes embodiments of the functional units of the map providing system 1 of the present invention based on the configuration of the mobile terminal 20 mounted on the vehicle 50 and the map providing server 30. Note that the embodiments of the functional units provided in the map providing server 30 of the present invention can be deployed so as to be executed by a single computer, or in a distributed manner on multiple computers located in one location or distributed across several locations and interconnected by a communication network. Furthermore, the system can also be configured using multiple virtual computers on the cloud.

[0060] <Operation of this embodiment> Next, the operation of estimating and clustering candidate hard braking locations performed by the map providing server 30 of this embodiment will be described with reference to the flowchart of FIG. When estimating the location of sudden braking, the area including the road where the sudden braking location is to be estimated and the period during which the vehicle will be traveling are set in advance, and the vehicle position information table 321 for that period and that area is created in advance.

[0061] In step S1, the sudden braking candidate location estimation unit 313 calculates a set {A(j)} of location information of sudden braking candidate locations based on location information measured over time at predetermined time intervals for each vehicle (each mobile ID) from the vehicle location information table 321, and calculates the union of these sets (for all vehicles 50) to obtain the location set for the sudden braking candidate locations.

[0062] In step S2, the clustering processing unit 314 calculates a Corepoint, a Borderpoint, and a Noisepoint from the sudden braking candidate location set {A(j)} calculated by the sudden braking candidate location estimation unit 313 based on two parameters (eps and MinPts).

[0063] In step S3, the clustering processing unit 314 removes the noise points and calculates cluster regions including the core points and the border points.

[0064] In step S4, the clustering processing unit 314 displays cluster areas including the core points and border points that make up the clusters on a map representing the area, thereby creating a near-miss map. Figure 9 shows an image of the cluster regions calculated in this way plotted on a map.

[0065] The manager may evaluate the accuracy of the near-miss map created in step S4, and based on the evaluation results, modify one or both of the two parameters, and then start operation from step S2.

[0066] According to the operation of this embodiment described above, the map providing server 30 can create a near-miss map with a simple configuration in which it acquires, at predetermined time intervals, position information and vehicle speed information measured by the positioning sensor 24 provided in many mobile terminals 20. Furthermore, by providing this information to end users and alerting them, it becomes possible to avoid the risk of accidents and the like at locations where sudden stops are required. This completes the description of this embodiment.

[0067] <Modification> Although the above-described embodiment is a preferred embodiment of the present invention, the scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, modifications such as those described below can be made.

[0068] For example, the functional configurations shown in Figures 1, 2, and 3 are merely examples and do not limit the functional configuration of this embodiment. In other words, it is sufficient for each device to have the function of being able to execute a series of processes related to the map providing system of the present invention as a whole, and the functional blocks used to realize these functions are not particularly limited to the examples shown in Figures 1, 2, and 3.

[0069] As another modification, the mobile terminal 20 may be replaced by the in-vehicle device 10, for example. Furthermore, as another modification, although the above embodiment has been described as realizing the map providing server 30 by a single server device or the like, the functions of the map providing server may be distributed among a plurality of server devices as appropriate, forming a distributed processing system. Also, the functions of the map providing server may be realized by using a virtual server function or the like on a cloud. Furthermore, as another modification, the location information 121 may include altitude information in addition to the latitude and longitude information of the measured position. By using the altitude transition obtained from the altitude information, it is possible to take into account uphill and downhill slopes, and it becomes possible to more accurately estimate locations on the road where sudden braking occurs frequently.

[0070] Furthermore, as another modified example, an FCD (Floating Car Data) server (tentative name) may be provided separately from the map providing server 30, and the FCD server may receive the vehicle information 120 of each vehicle 50 at predetermined time intervals from the vehicle 50. In this way, the map providing server may acquire the vehicle information 120 of each vehicle 50 transmitted at predetermined time intervals from the FCD server. Furthermore, as another modified example, the FCD server may construct and appropriately create and update the vehicle position information table 321 based on the vehicle information 120 etc. received from each vehicle 50. In this case, the map providing server 30 may appropriately acquire the information stored in the vehicle position information table 321 from the FCD server.

[0071] Furthermore, as another modified example, an input / output interface with the user may be realized via a user terminal (not shown) that is connected to the communication network 60 and is capable of communicating with the map providing server 30. Specifically, for example, after a user logs in to the map providing server 30 from a user terminal and the map providing server 30 determines that the user ID is valid, the map providing server 30 generates a user interface screen and provides the generated user interface screen to the user terminal, so that the user can inquire of the map providing server 30 about, for example, near-miss locations via the user terminal.

[0072] <About hardware and software> Each of the devices included in the above navigation system can be realized by hardware, software, or a combination of these. Furthermore, the navigation method performed by the cooperation of each of the devices included in the above navigation system can also be realized by hardware, software, or a combination of these. "Realized by software" here means that the method is realized by a computer reading and executing a program.

[0073] The program can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be supplied to a computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable media can supply the program to a computer via a wired communication path such as an electric wire or optical fiber, or via a wireless communication path. [Explanation of symbols]

[0074] 1. Map provision system 10 Onboard equipment 20 Mobile devices 21 Control section 211 Vehicle information transmission unit 22 Memory section 221 Vehicle Information 23 Communications Department 24 Positioning Sensor 25 Display section 26 Input section 30 Map provider server 31 Control Unit 311 Vehicle information receiving unit 312 Position selection section 313 Sudden braking candidate location estimation unit 314 Clustering Processing Unit 32 Storage section 321 Vehicle Location Information Table 322 Map information storage unit 33 Communications Department 50 vehicles 60 Communication Network

Claims

1. a vehicle information receiving unit that receives vehicle information including time transitions of position information at predetermined time intervals of at least 10 seconds from positioning sensors mounted on a plurality of vehicles traveling on a road; a map section having road map information; a location selection unit that selects, for specific second location information among the location information, first location information recorded a predetermined time before the second location information and third location information that is a location after the predetermined time from the second location information, from the vehicle information; an estimation unit that calculates an average speed of the vehicle from a combination of speed information at the time of acquisition of the first position information and speed information at the time of acquisition of the second position information, or speed information at the time of acquisition of the second position information and speed information at the time of acquisition of the third position information, calculates an estimated position after the predetermined time from the average speed and the second position information as estimated position information, and estimates a point of the second position information where a deviation rate between the third position information and the estimated position information is equal to or greater than a predetermined value as a sudden braking candidate location; a clustering processing unit that performs clustering processing on the sudden braking candidate locations estimated for each of the plurality of vehicles to calculate sudden braking areas and plot the areas on the road map; A map providing server comprising:

2. 2. The map providing server according to claim 1, wherein the clustering processing unit uses a DBSCAN method as a clustering processing method, which performs clustering based on data density, and the sudden braking area is an area formed by the clustering processing.

3. The estimation unit a distance between the second location information and the estimated location information; The difference in distance between the second position information and the third position information is The value obtained by dividing the average speed 3. The map providing server according to claim 1, wherein the deviation rate is determined by the following formula:

4. The estimation unit a distance between the second location information and the estimated location information; The difference in distance between the second position information and the third position information is a division value obtained by dividing the second position information by the distance between the second position information and the estimated position information; 3. The map providing server according to claim 1, wherein the deviation rate is determined by the following formula:

5. 1. A map providing method performed by one or more computers equipped with road map information, comprising: a vehicle information receiving step of receiving vehicle information including time transition of position information at a predetermined time interval of at least 10 seconds from positioning sensors mounted on a plurality of vehicles traveling on a road; a location selection step of selecting, from the vehicle information, for specific second location information among the location information, first location information recorded a predetermined time before the second location information and third location information that is a location after the predetermined time from the second location information; an estimation step of calculating an average speed of the vehicle from a combination of either speed information at the time of acquisition of the first position information and speed information at the time of acquisition of the second position information, or speed information at the time of acquisition of the second position information and speed information at the time of acquisition of the third position information, calculating an estimated position after the predetermined time from the average speed and the second position information as estimated position information, and estimating a point of the second position information where a deviation rate between the third position information and the estimated position information is equal to or greater than a predetermined value as a candidate location for sudden braking; a clustering processing step of calculating a sudden braking area by performing clustering processing on the sudden braking candidate locations estimated for each of the plurality of vehicles and plotting the sudden braking area on the road map; A map providing method comprising:

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