Map provision server and map provision method

Abstract

The system estimates the emergency braking area based on the vehicle's location information. [Solution] A map providing server characterized by estimating potential locations for sudden braking by acquiring vehicle information including the temporal progression of location information measured at predetermined time intervals from positioning sensors mounted on multiple vehicles traveling on a road or portable terminals used by users riding in each vehicle, and vehicle speed information at the same time, and calculating sudden braking areas by clustering the potential locations for sudden braking and plotting them on a road map.

Description

Technical Field

[0001] The present invention relates to a map providing server and a map providing method that estimate a hard braking location based on vehicle position data measured at a predetermined time interval of at least 10 seconds or more and plot it on a road map.

Background Art

[0002] For the purpose of preventing traffic accidents, technologies have been developed to share so-called "near misses" information and alert users. For example, in Patent Document 1, as a map providing server, driving information including the occurrence and location of hard braking is acquired from a plurality of vehicles, and locations where hard braking frequently occurs are arranged on a map and associated with the arranged dangerous locations, and it is disclosed that a user's contribution can be received.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technology described in the patent document, in order to identify locations where hard braking frequently occurs, it is necessary to acquire information regarding the occurrence of hard braking from vehicles. For this purpose, for example, it is necessary to equip vehicles with sensors such as acceleration sensors and mount smartphones, etc. However, equipping vehicles with sensors is not practical because it leads to an increase in the selling price, for example, in the case of inexpensive motorcycles. Also, even when mounting a smartphone, consent on the application by the user is required for data acquisition, and it is difficult to obtain consent because the data is not directly beneficial to the user, and there is also a need for the application provider to reduce the data to be acquired as much as possible due to management problems. Therefore, it is desirable to identify locations where sudden braking frequently occurs using location data, without acquiring data from acceleration sensors.

[0005] The present invention aims to provide a map provision server and a map provision method that enable the estimation and plotting of locations where sudden braking frequently occurs by acquiring vehicle information, including the temporal progression of vehicle location information, which is measured at predetermined time intervals of at least 10 seconds from positioning sensors (for example, positioning sensor 24 described later) mounted on multiple vehicles traveling on a road or on mobile terminals paired with vehicles. This makes it possible to estimate locations on roads where sudden braking frequently occurs with a simple configuration that utilizes measurement information from positioning sensors equipped on many vehicles. [Means for solving the problem]

[0006] (1) The map provision server of the present invention (for example, the map provision server 30 described later) includes a vehicle information receiving unit (for example, the vehicle information receiving unit 311 described later) that receives vehicle information including the temporal progression of location information from positioning sensors (for example, the positioning sensor 24 described later) mounted on a plurality of vehicles (for example, the vehicle 50 described later) traveling on a road at predetermined time intervals of at least 10 seconds, a map unit (for example, the map information storage unit 322 described later) that has road map information, a location selection unit (for example, the location selection unit 312 described later) that selects from the vehicle information, for a specific second location information, a first location information recorded before a predetermined time before the second location information and a third location information which is the position after a predetermined time of the second location information, and speed information at the time of acquisition of the first location information, The system includes an estimation unit (for example, an emergency braking candidate location estimation unit 313 described later) that calculates the average speed of the vehicle from either the speed information at the time of acquisition of the second location information, or a combination of the speed information at the time of acquisition of the second location information and the speed information at the time of acquisition of the third location information, calculates the estimated position after a predetermined time from the average speed and the second location information as estimated location information, and estimates the location of the second location information where the deviation rate between the third location information and the estimated location information is greater than or equal to a predetermined value as an emergency braking candidate location, and a clustering processing unit (for example, a clustering processing unit 314 described later) that calculates an emergency braking area by clustering the emergency braking candidate locations estimated for each of the multiple vehicles and plots it on the road map.

[0007] According to (1) above, a simple configuration that acquires measurement information (location data) from positioning sensors equipped in many vehicles at predetermined time intervals of at least 10 seconds makes it possible to estimate locations on roads where sudden braking frequently occurs. For this reason, it can be applied to multiple vehicles, especially inexpensive motorcycles, and by reducing the amount of data transmitted, it can solve management problems and reduce communication costs related to such transmission.

[0008] (2) In the map provision server described in (1) above (for example, the map provision server 30 described later), the clustering processing unit (for example, the clustering processing unit 314 described later) may use the DBSCAN method, which determines clustering based on data density, as the method for the clustering process, and the sudden braking area may be the area formed by the clustering process.

[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 frequently occurs.

[0010] (3) In the map provision server described in (1) or (2) above (for example, the map provision server 30 described later), the estimation unit (for example, the emergency braking candidate location estimation unit 313 described later) may use a deviation rate defined by a division value obtained by dividing the difference between the distance between the second location information and the estimated location information and the distance between the second location information and the third location 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 at predetermined time intervals in chronological order, it becomes possible to accurately estimate locations where sudden braking frequently occurs.

[0012] (4) In the map provision server described in (1) or (2) above (for example, the map provision server 30 described later), the estimation unit (for example, the emergency braking candidate location estimation unit 313 described later) may use a deviation rate defined by a division value obtained by dividing the difference between the distance between the second location information and the estimated location information and the distance between the second location information and the third location information by the distance between the second location information and the estimated location 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 at predetermined time intervals in chronological order, it becomes possible to accurately estimate candidate locations where sudden braking frequently occurs.

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

[0015] According to the method described in (5) above, the same effect as the map provision server described in (1) above is achieved. [Effects of the Invention]

[0016] According to the present invention, it is possible to estimate a location where sudden braking frequently occurs on a road with a simple configuration that acquires measurement information (position data) of a positioning sensor provided in many vehicles at a predetermined time interval of at least 10 seconds or more. For this reason, for example, when applied to a plurality of vehicles, particularly inexpensive motorcycles, by reducing the data to be transmitted, it is possible to solve management problems and reduce communication costs related to the transmission, and by plotting on a map, it is possible to alert many users. Therefore, it contributes to the improvement of the environment and life of "realizing an inclusive, safe, resilient, and sustainable city and human settlement", and is suitable for the realization of the development goal (SDGs11) of enabling safe and sustainable means of transportation.

Brief Explanation of Drawings

[0017] [Figure 1] It is a block diagram showing the basic configuration of the entire map providing system which is an embodiment of the present invention. [Figure 2] It is a functional block diagram showing the functional configuration of a mobile terminal in an embodiment of the present invention. [Figure 3] It is a functional block diagram showing the functional configuration of a map providing server in an embodiment of the present invention. [Figure 4] It is a table showing an example of a vehicle position information table in an embodiment of the present invention. [Figure 5] It is a diagram showing an example of the traveling distance at the time of sudden braking and the traveling distance when sudden braking does not occur in an embodiment of the present invention. [Figure 6] It is a diagram showing an example of three types of data points handled by DBSCAN used in an embodiment of the present invention. [Figure 7] It is a diagram showing an example of a cluster and noise not assigned to the cluster in an embodiment of the present invention. [Figure 8] It is a flowchart showing the basic operation of a map providing server in an embodiment of the present invention. [Figure 9] It is an image diagram in which a plurality of clusters are plotted on a map in an embodiment of the present invention.

Best Mode for Carrying Out the Invention

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

[0019] <Overall Configuration of Map Providing System 1> A map providing system 1 according to a preferred embodiment of the present invention will be described. FIG. 1 shows the overall configuration of the map providing system 1.

[0020] As shown in FIG. 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 and the vehicle 50 are assumed to be a motorcycle, but the in-vehicle device 10 can be applied instead of the mobile terminal 20, and a normal four-wheeled vehicle can be applied instead of the motorcycle. The map providing server 30 and the mobile terminal 20 used by a user riding in the vehicle 50 are communicably connected to each other via a communication network 60. In the figure, the information transmitted and received between the map providing server 30 and each mobile terminal 20 is also illustrated, but these are merely examples. In this embodiment, information other than that illustrated may be transmitted and received. In this embodiment, a case where the vehicle information is transmitted from the mobile terminal 20 to the map providing server 30 will be described, but the mobile terminal 20 may be replaced with the in-vehicle device 10.

[0021] The mobile terminal 20 is a portable terminal used by a user riding 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 periodically transmits location information, which it has measured at predetermined time intervals of at least 10 seconds, to the map provision server 30, linking it to a mobile ID, which is identification information for identifying the mobile terminal 20. Here, since the mobile terminal 20 and the vehicle 50 are used as a one-to-one pair, the transmitted location information can be considered as essentially the location information of the vehicle 50. In addition, 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 provision server 30. As a mobile ID, for example, the telephone number assigned to the SIM (Subscriber Identity Module) inserted into the communication unit 13 in order for the communication unit 13 to connect to the communication network 60, which is a network such as a mobile phone network, can be used as the mobile ID. In addition, other numbers such as the VIN (Vehicle Identification Number) or license plate number uniquely assigned to the vehicle 50 can also be used. In this way, the map provision server 30 can obtain vehicle information for each mobile entity ID, including time information (timestamp) of the vehicle's position measured at predetermined time intervals, vehicle location information, and vehicle speed information at that time. In the following explanation, the vehicle 50 and the mobile terminal 20 will also be referred to as "mobile entities" as appropriate. Such a mobile device 20 can be realized by a smartphone, mobile phone, tablet, laptop computer, or other portable electronic device.

[0023] The map provision server 30 is a device that estimates locations where sudden braking frequently occurs and plots them on a map by acquiring vehicle information, including the temporal changes in location information measured at predetermined time intervals from positioning sensors 24 mounted on portable terminals carried by each vehicle traveling on the road or by users riding in each vehicle, as well as vehicle speed information at the same time.

[0024] Vehicle 50 is a mobile vehicle in which the user of the mobile terminal 20 rides. In this embodiment, vehicle 50 is realized by a motorcycle or the like.

[0025] The communication network 60 is realized by networks such as the Internet and mobile phone networks, or networks that combine these. Before explaining the map provision server 30, let me briefly explain the mobile terminal 20.

[0026] <Regarding mobile device 20> As shown in Figure 2, the mobile terminal 20 is composed of 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 consists of an arithmetic processing unit such as a microprocessor and controls each part that makes up the mobile terminal 20.

[0028] The memory unit 22 is composed of semiconductor memory and stores various programs such as firmware and an operating system for control, a program for transmitting vehicle information including the temporal changes in the location information and speed information of the vehicle 50, which are measured at predetermined time intervals, to the map provision server 30, and other information such as map information.

[0029] The figure illustrates vehicle information 221, which includes location information measured at predetermined time intervals for the vehicle 50, time information for the measurement, and speed information of the vehicle 50 at that time, as information stored in the memory unit 22. The predetermined time interval is at least 10 seconds, and may be, for example, 30 seconds. As mentioned above, the mobile ID is information used to identify vehicle 50. The location information is the location information (latitude and longitude information) of the mobile terminal 20 (vehicle 50) determined by the positioning sensor 24, and the location information 121 includes not only information indicating the determined location but also the time the positioning was performed. The speed information is, for example, the speed information of vehicle 50 at the time of positioning, obtained from the ECU of vehicle 50.

[0030] The communication unit 23 has a DSP (Digital Signal Processor), etc., and enables wireless communication with the map provision 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, which is stored in the storage unit 22 and acquired at predetermined time intervals of at least 10 seconds, to the map provision server 30. In this way, since the communication unit 23 transmits vehicle information at predetermined time intervals, communication costs can be significantly reduced. In addition, the amount of data that requires user consent can be reduced.

[0031] The positioning sensor 24 is composed of, for example, a GPS (Global Positioning System) sensor. The positioning sensor 24 functions as a position detection means for detecting location information, and receives GPS satellite signals using the GPS sensor to determine the location information (latitude and longitude) of the mobile terminal 20. Positioning by the positioning sensor 24 is performed at predetermined time intervals (for example, every 30 seconds) as described above. The determined location information is stored in the storage unit 22 as vehicle information 221. The display unit 25 is composed of a display device such as a liquid crystal display or an organic electroluminescent panel. The display unit 25 displays an image in response to instructions from the control unit 21. The input unit 26 consists of input devices such as physical switches called a numeric keypad and a touch panel (not shown) mounted on top of 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 the part that performs contactless short-range communication compliant with 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, vehicle 50, although not shown, is equipped with a short-range communication unit for communicating with the short-range communication unit 27. For example, the ECU (Electronic Control Unit) of vehicle 50 is equipped with a short-range communication unit. Furthermore, the case in which the mobile terminal 20 can communicate with the ECU via short-range communication is, for example, when the mobile terminal 20 is located inside the vehicle 50. In the case of a motorcycle, for example, this would be when the mobile terminal 20 is mounted in the cockpit of the motorcycle or carried by the driver. The position information determined 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 be configured to activate the vehicle information transmission unit 211 as long as it can communicate with the vehicle's ECU via, for example, the short-range communication unit 27. The activated vehicle information transmission unit 211 then transmits the location information of the vehicle 50, which has been positioned by the positioning sensor 24, to the map provision server 30 as vehicle information 221, along with the mobile ID, time information (timestamp), and the vehicle's speed information at that time obtained from the vehicle's ECU, at predetermined time intervals.

[0035] For example, when a user boards a vehicle 50 with a mobile terminal 20 and turns on the vehicle 50's ignition switch or other starting switch, the vehicle 50 and the mobile terminal 20 are connected (paired). Subsequently, the mobile terminal 20, paired with the vehicle 50, will transmit vehicle information 221, which includes vehicle speed information acquired from the vehicle 50 at predetermined time intervals and the latitude and longitude location information of the mobile terminal 20 (which is also the location information of the vehicle 50), to the map provision server 30 each time, linking it to a mobile ID. Furthermore, when the ignition switch or other starting switch of the vehicle 50 is turned off, the pairing between the vehicle 50 and the mobile terminal 20 is canceled, and the acquisition of vehicle information 221 and its transmission to the map provision server 30 are terminated. The mobile terminal 20 may also be configured to collect multiple pieces of vehicle information obtained at predetermined time intervals and send them to the map provision server 30 in batches, for example, within a predetermined time range.

[0036] Furthermore, if the vehicle 50 is equipped with an in-vehicle device 10 that has a function for determining location information, the in-vehicle device 10, which has a configuration equivalent to that of the mobile terminal 20, may perform the same processing as the aforementioned mobile terminal 20.

[0037] <About Map Provisioning Server 30> Next, the functional blocks provided by the map provisioning server 30 will be explained with reference to the block diagram in Figure 3.

[0038] As shown in Figure 3, the map provision server 30 is configured to include a control unit 31, a storage unit 32, and a communication unit 33.

[0039] The control unit 31 consists of a processing unit such as a microprocessor and controls each part that makes up the map provision server 30. Details of the control unit 31 will be described later.

[0040] The memory unit 32 is composed of semiconductor memory and stores various programs such as firmware and operating systems (control programs), programs for calculating emergency braking areas, and map information. Furthermore, the storage unit 32 stores vehicle location information transmitted from the mobile terminal 20 as a vehicle location information table 321. Figure 4 shows an example of the vehicle location information table 321 in an embodiment of the present invention.

[0041] As shown in Figure 4, the vehicle location information table 321 stores temporal transition information for each vehicle 50, including at least the "mobile ID", "positioning time information" for each predetermined time interval, "vehicle location information at the positioning time (e.g., latitude and longitude information)", and "vehicle speed information at the positioning time". The "temporal progression" in the vehicle location information table 321 refers to the location information measured at predetermined time intervals received from the moving object from the start of transmission of location information, speed information, etc., until the end of transmission. The storage unit 32 may also include a map information storage unit 322 that contains, for example, information about roads, display map data for displaying a background such as a road map, location information and type information of nodes (e.g., road intersections, bends, endpoints, etc.), location information and type information of links which are routes connecting each node, and link cost data related to the cost information of all links (e.g., distance, travel time, etc.).

[0042] The communication unit 33 has a DSP and other components, and enables wireless and wired communication with other devices (e.g., mobile terminal 20) 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 33 is used to receive vehicle information, including mobile 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 details of the control unit 31 will be explained. The control unit 31 is composed of a microprocessor having a CPU, RAM, ROM, and I / O. The CPU executes each program read from the ROM or storage unit 32, and during execution, it 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 through the cooperation of hardware and software (programs).

[0044] The control unit 31 includes, as functional blocks, a vehicle information receiving unit 311, a position selection unit 312, a sudden braking candidate location estimation 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, which has been determined by positioning sensors 24 mounted on multiple mobile bodies traveling on the road, along with the vehicle's mobile body ID, time information (timestamp), and speed information of the vehicle 50 at that time, as vehicle information from each mobile body. The vehicle information receiving unit 311 creates a vehicle location information table 321, shown in Figure 4, based on vehicle information received from a moving object and measured or acquired at predetermined time intervals, which represents the temporal progression data for each vehicle. The vehicle information receiving unit 311 may also be configured to create a vehicle location information table 321 for a predetermined area and a predetermined period. This allows, for example, the display of near-miss information within that area.

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

[0047] Position information of vehicle 50, measured at predetermined time intervals and corresponding to the temporal progression. Let P(i)(1≦i≦N){where N is the total number of predetermined time intervals related to the vehicle}. The position selection unit 312 selects the position information of the vehicle in accordance with its temporal progression, For each i such that 1 ≤ i ≤ N-2, the following three adjacent positional information points are obtained. 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, Let P(i) be named the first position, P(i+1) the second position, and P(i+2) the third position.

[0049] If the speed information of the vehicle at the first position P(i), second position P(i+1), and third position P(i+2) selected by the position selection unit 312 is V(i), V(i+1), and V(i+2), respectively, then 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] <Estimation unit for potential sudden braking locations 313> The emergency 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) based on 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, the emergency braking candidate location estimation unit 313 can calculate the estimated position P'(i+2) as the estimated position P'(i+2) if it assumes that the vehicle traveled at an average speed V'(i) from the second position P(i+1) towards the third position P(i+2) over a predetermined period of time.

[0051] Figure 5 shows an example of the distance traveled when sudden braking occurs and when sudden braking does not occur, when traveling from the second position P(i+1) towards the third position P(i+2). 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, and then accelerate to reach the third position P(i+2) after a predetermined time, the difference between the distance traveled from the second position P(i+1) to the third position P(i+2) (Xact) and the estimated distance Xest from the second position P(i+1) to the estimated position P'(i+2), which is obtained assuming that no sudden braking incident occurred and the vehicle drove smoothly, is shown. Xest > Xact It is thought that this will occur. The emergency braking candidate location estimation unit 313 can calculate a deviation rate in order to make a relative judgment on the deviation. Deviation rate = (Xest - Xact) / Xest The emergency braking candidate location estimation unit 313 determines the second position P(i+1) as the emergency braking candidate location A(j) if the deviation rate exceeds or is equal to a preset threshold. In this way, the emergency braking candidate location estimation unit 313 can calculate the emergency braking candidate location A(j) for all vehicles. As mentioned above, the location information is latitude and longitude, and the distance between two locations is calculated, for example, as the straight-line distance between the two latitudes and longitudes. Similarly, the direction of the estimated location is calculated, for example, as the direction from the second location to the third location.

[0052] As described above, the emergency braking candidate location estimation unit 313 selects a 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 a deviation rate (i) based on the third position information P(i+2) and estimated position information P'(i+2). For example, the set of second positions P(i+1) calculated for each vehicle whose deviation rate exceeds or is equal to a threshold can be used as a subset of the emergency braking candidate location set. Then, by creating a union of the emergency braking candidate location subsets calculated for each vehicle, a set consisting of emergency braking candidate locations in a pre-defined area can be calculated.

[0053] Furthermore, the emergency braking determination by the emergency braking candidate location estimation unit 313 is expected to include noise such as the set of emergency braking candidate locations {A(j)}, because discrepancies between the actual travel distance Xact and the estimated distance Xest are expected to occur not only in cases of emergency braking but also in normal speed control, for example. This type of noise can be dealt with by noise reduction through clustering, as will be discussed later.

[0054] Furthermore, in the above embodiment, the average speed V'(i) when the vehicle travels from the second position P(i+1) to the third position P(i+2) was the average speed of the vehicle from the first position P(i) to the second position P(i+1), but this is not limited to this. If speed information is available at each position, 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 applied. V´´(i) = (V(i+1)+V(i+2)) / 2

[0055] Furthermore, in the above embodiment, 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, a different calculation method may be used, where 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 is divided 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 calculates the emergency braking area by clustering the set of emergency braking candidate locations {A(j)} calculated by the emergency braking candidate location estimation unit 313. Specifically, the clustering processing unit 314 uses the DBSCAN (Density-Based Spatial Clustering) method as a clustering technique, for example, by determining clustering based on data density. In this way, the sudden braking area can be calculated as the area formed by the clustering process.

[0057] DBSCAN is a clustering method in which two parameters (radius eps and the minimum number of points that make up a cluster, MinPts) are predetermined, and points that fall within a circle drawn with that radius are considered to belong to the same cluster and are divided accordingly. Figure 6 shows an example of the 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, the data points within the eps range are classified into Corepoints (which include data points greater than or equal to MinPts), Borderpoints (where the data points within the eps range are less than MinPts and include Corepoints), and Noisepoints (where the data points within the eps range are less than MinPts and do not include Corepoints). A Borderpoint is a data point from a Corepoint and is assigned to the same cluster as the Corepoint that is reachable from that Corepoint. Noisepoint is not assigned to a cluster as it is considered noise. For example, two parameters could be set as follows: eps = 50m and MinPoints = 3. Note that the two parameter values ​​(eps and MinPoints) may be changed as appropriate depending on the predetermined time interval for positioning, the final estimated result of the sudden braking area, etc.

[0058] For example, at locations where sudden braking frequently occurs (near misses), it is estimated that points (Corepoints and Borderpoints) estimated as potential sudden braking locations by the sudden braking location estimation unit 313 are clustered together. Therefore, as shown in Figure 7, by removing points (Noisepoints) that are far from the locations where near misses estimated by DBSCAN are concentrated, it is expected that the accuracy of the area considered to be a near miss location will improve. Thus, according to the present invention, it is possible to estimate the location of sudden braking using only position data obtained by positioning at predetermined time intervals (for example, 30 seconds). The configuration of each functional unit of the map provisioning server 30, which was illustrated as an example of this embodiment, has been described above.

[0059] The embodiments of each functional unit of the map provision system 1 of the present invention have been described above based on the configuration of the mobile terminal 20 mounted on the vehicle 50 and the map provision server 30. The embodiments of each functional unit of the map provision server 30 of the present invention can be deployed to run on a single computer, or on a large number of computers located in one or several locations and interconnected by a communication network. Furthermore, they can also be configured using multiple virtual computers on the cloud.

[0060] <Operation of this embodiment> Next, with reference to the flowchart in Figure 8, the estimation and clustering operations of the map provisioning server 30 in this embodiment for potential sudden braking locations will be described. Furthermore, when estimating the location of sudden braking, the area including the road where the sudden braking location is to be estimated and the period of vehicle travel are set in advance, and the vehicle location information table 321 for that period and area is created in advance.

[0061] In step S1, the emergency braking candidate location estimation unit 313 calculates a set of location information {A(j)} for emergency braking candidate locations from the vehicle location information table 321 for each vehicle (for each mobile ID) based on location information that follows the temporal progression measured at predetermined time intervals, calculates the union of this set (for all vehicles 50) and uses it as the location set relating to emergency braking candidate locations.

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

[0063] In step S3, the clustering processing unit 314 removes the Noisepoint and calculates the cluster area including the Corepoint and Borderpoint.

[0064] In step S4, the clustering processing unit 314 displays the cluster area, including the Corepoint and Borderpoint that constitute the cluster, on a map representing the area, and creates a near-miss map. Figure 9 shows an image of the cluster regions calculated in this way plotted on a map.

[0065] Furthermore, the administrator may evaluate the accuracy of the near-miss map created in step S4 and, depending on the evaluation results, modify one or both of the two parameters to allow operation from step S2.

[0066] As described above, according to the operation of this embodiment, the map provision server 30 can create a near-miss map with a simple configuration that acquires location information and vehicle speed information obtained by positioning sensors 24, which are equipped in many mobile terminals 20, at predetermined time intervals. Furthermore, by providing this information to end users and raising awareness, it becomes possible to avoid risks such as accidents at locations where sudden stops are required. This embodiment has been described above.

[0067] <Variation> While the embodiments described above are preferred embodiments of the present invention, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the invention can be implemented in modified forms such as those described below.

[0068] For example, the functional configurations shown in Figures 1, 2, and 3 are merely illustrative and do not limit the functional configuration of this embodiment. In other words, it is sufficient that each device is equipped with a function that can execute a series of processes related to the map provisioning system of the present invention as a whole, and the type of functional block used to realize this function is not particularly limited to the examples in Figures 1, 2, and 3.

[0069] Another variation is that the mobile terminal 20 may be replaced with, for example, an in-vehicle device 10. Furthermore, as another variation, although the above embodiment described the map provision server 30 as being implemented by a single server device, it may also be implemented as a distributed processing system in which each function of the map provision server is distributed among multiple server devices as appropriate. Alternatively, each function of the map provision server may be implemented using virtual server functions on the cloud. Furthermore, as another variation, the location information 121 may include altitude information in addition to latitude and longitude information as the measured position. By using the altitude changes obtained from the altitude information, uphill and downhill slopes can be taken into account, making it possible to estimate with higher accuracy the locations on the road where sudden braking frequently occurs.

[0070] Furthermore, as another variation, a separate FCD (Floating Car Data) server (tentative name) may be provided in addition to the map provision server 30, and the FCD server may receive vehicle information 120 of each vehicle 50 at predetermined time intervals. In this way, the map provision server may acquire the vehicle information 120 of each vehicle 50 transmitted from the FCD server at predetermined time intervals. Furthermore, as another variation, the FCD server may construct a vehicle location information table 321 based on vehicle information 120 received from each vehicle 50, and update it as needed. In that case, the map provision server 30 may appropriately retrieve the information stored in the vehicle location information table 321 from the FCD server.

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

[0072] <Regarding hardware and software> Each of the devices included in the above navigation system can be implemented using hardware, software, or a combination thereof. Furthermore, the navigation method performed by the cooperation of each of the devices included in the above navigation system can also be implemented using hardware, software, or a combination thereof. Here, implementation by software means implementation by a computer loading and executing a program.

[0073] Programs 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 memory (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory)). Programs may also be supplied to a computer using various types of transient computer-readable media. Examples of transient computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable media can be supplied to a computer via wired communication channels such as electric wires and optical fibers, or via wireless communication channels. [Explanation of symbols]

[0074] 1. Map provision system 10 Onboard equipment 20 Mobile devices 21 Control Unit 211 Vehicle Information Transmission Unit 22 Memory section 221 Vehicle Information 23 Communications Department 24 positioning sensors 25 Display section 26 Input section 30 Map provision server 31 Control Unit 311 Vehicle Information Receiving Unit 312 Position Selection Section 313 Estimation unit for potential emergency braking locations 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 the temporal changes in location information, from positioning sensors mounted on multiple vehicles traveling on a road at predetermined time intervals of at least 10 seconds, A map section containing road map information, A position selection unit selects, from the vehicle information, a specific second position information from the position information, a first position information recorded before a predetermined time before the second position information, and a third position information which is the position after a predetermined time after the second position information. An estimation unit calculates the average speed of the vehicle from any one combination of the speed information at the time of acquisition of the first location information and the speed information at the time of acquisition of the second location information, or the speed information at the time of acquisition of the second location information and the speed information at the time of acquisition of the third location information, calculates the estimated position after a predetermined time from the average speed and the second location information as estimated position information, and estimates the location of the second location information where the deviation rate between the third location information and the estimated position information is greater than or equal to a predetermined value as a candidate location for sudden braking, A clustering processing unit calculates emergency braking areas by clustering the estimated emergency braking candidate locations for each of the multiple vehicles and plots them on the road map. A map-providing server characterized by having the following features.

2. The map providing server according to claim 1, characterized in that the clustering processing unit uses the DBSCAN method, which determines clustering based on data density, as the clustering processing method, and the sudden braking area is the area formed by the clustering processing.

3. The estimation unit, The distance between the second position information and the estimated position information, The difference between the distance between the second position information and the third position information is The division value obtained by dividing by the average speed mentioned above. A map provisioning server according to claim 1 or 2, characterized in that it uses the deviation rate defined by [the specified method].

4. The estimation unit, The distance between the second position information and the estimated position information, The difference between the distance between the second position information and the third position information is The division value obtained by dividing by the distance between the second position information and the estimated position information. A map provisioning server according to claim 1 or 2, characterized in that it uses the deviation rate defined by [the specified method].

5. A method for providing maps using one or more computers equipped with road map information, A vehicle information receiving step, which receives vehicle information including the temporal progression of location information from positioning sensors mounted on multiple vehicles traveling on a road at predetermined time intervals of at least 10 seconds, A position selection step in which, from the vehicle information, a specific second position information is selected, and a first position information recorded before a predetermined time before the second position information and a third position information which is the position after a predetermined time after the second position information. An estimation step in which the average speed of the vehicle is calculated from any one combination of the speed information at the time of acquisition of the first location information and the speed information at the time of acquisition of the second location information, or the speed information at the time of acquisition of the second location information and the speed information at the time of acquisition of the third location information, the estimated position after the predetermined time is calculated from the average speed and the second location information as estimated location information, and the location of the second location information where the deviation rate between the third location information and the estimated location information is greater than or equal to a predetermined value is estimated to be a candidate location for sudden braking, A clustering process step which calculates emergency braking areas by clustering the estimated emergency braking candidate locations for each of the multiple vehicles and plots them on the road map, A method for providing maps, characterized by comprising the following features.

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