Map processing device and map processing method

Abstract

To achieve both of capacity reduction of a storage which holds map data in a device and performance maintenance of the device in a map processing device used for travel support of a vehicle.SOLUTION: A map processing device according to the present invention includes a map data look-ahead part which can acquire multiple types of map data including lane connection data showing connection information between lane sections in the extension direction of a lane and lane group connection data showing connection information between lane group sections in the extension direction of the lane group consisting of one or more lanes, and acquires the type of map data according to the conditions of a prescribed point when acquiring the map data of the prescribed point in front of the own vehicle.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a map processing apparatus and a map processing method. [Background Art]

[0002] Conventionally, a technique for pre-reading map data in a map creation application used in electronic map display systems and the like has been disclosed (see, for example, Patent Document 1). Patent Document 1 discloses a technique of extracting map data by selecting map data tiles for an area including a first route and an area including a secondary route (such as a return route) selected based on the first route from all available map data. In the map data pre-reading technique disclosed in Patent Document 1, map data for a secondary route is pre-read based on the first route, and the amount of accessed map data is adjusted based on the priority of the secondary route. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese National Publication of International Patent Application No. 2015-501956 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] As described above, techniques for pre-reading map data in a map processing apparatus have been conventionally proposed. In this technical field, there is a demand for reducing the capacity of storage that holds map data in the apparatus to lower costs. To solve this problem, it is necessary to reduce the volume of map data stored in the map processing apparatus, but if the volume of stored map data is excessively reduced, the performance of the map processing apparatus may be degraded. Therefore, in the technical field of map processing apparatuses, there is a demand for developing a technology that can achieve both reduction in the capacity of storage for holding map data in the apparatus and maintenance of the performance of the apparatus.

[0005] In particular, map processing devices that enable driving assistance at the lane level (hereinafter simply referred to as "lane"), which is necessary for autonomous driving of cars that has been under development in recent years, utilize map data with higher detail than conventional car navigation systems that can be used for driving assistance at the road level. Therefore, map processing devices that handle such high-detail map data also have a large capacity for map data to be stored in the device, and thus the above-mentioned demands are also large. For example, Patent Document 1 discloses a technology that predicts alternative routes (secondary routes) that can be expected from the vehicle's position and route, but on expressways, secondary routes tend to be long. Therefore, even if the technology disclosed in Patent Document 1 is applied to a map processing device that handles high-detail map data, it is difficult to predict all the map data for the secondary routes necessary for driving assistance.

[0006] Therefore, the present invention has been made to meet the above requirements. The objective of the present invention is to provide a technology that enables a reduction in the storage capacity required to hold map data within a map processing device used for vehicle driving assistance, while simultaneously maintaining the performance of the device. [Means for solving the problem]

[0007] To solve the above problems, the map processing device of the present invention includes a map data pre-reading unit capable of acquiring multiple types of map data. The multiple types of map data include lane connection data that shows connection information between lane sections in the direction of lane extension, and lane group connection data that shows connection information between lane group sections in the direction of lane group consisting of one or more lanes. When the map data pre-reading unit acquires map data for a predetermined point in front of the vehicle, it acquires map data of a type corresponding to the conditions of the predetermined point. The condition for a predetermined location is whether or not the predetermined location is on the vehicle's planned route. The map data pre-reading unit acquires lane connection data if the predetermined location is on the vehicle's planned route, and acquires lane group connection data if the predetermined location is on a route branching off from the vehicle's planned route.

[0008] Furthermore, in order to solve the above problems, the map processing method of the present invention includes the acquisition of map data of a type corresponding to the conditions of a predetermined location when the map data pre-reading unit of the map processing device of the present invention acquires map data of a type corresponding to the conditions of a predetermined location in front of the vehicle. The condition for a predetermined location is whether or not the predetermined location is on the vehicle's planned route. The map data pre-reading unit acquires lane connection data if the predetermined location is on the vehicle's planned route, and acquires lane group connection data if the predetermined location is on a route branching off from the vehicle's planned route. [Effects of the Invention]

[0009] According to the present invention with the above configuration, in a map processing device used for assisting vehicle driving, it is possible to achieve both a reduction in the storage capacity required to hold map data within the device and the maintenance of the device's performance. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an in-vehicle system including a map processing device according to one embodiment of the present invention. [Figure 2] This is a functional block diagram of a map processing device according to one embodiment of the present invention. [Figure 3] This diagram shows the relationship between various map data stored in the storage unit of a map processing device according to one embodiment of the present invention, and various applications that use the various map data. [Figure 4] This is a hardware configuration diagram of a map processing device according to one embodiment of the present invention. [Figure 5] This is a schematic diagram showing the relationship between various map data to be read in advance in a map processing device according to one embodiment of the present invention, and the distance from the vehicle's position to the point to be read in advance. [Figure 6] This flowchart shows the procedure for pre-fetching various map data using a map processing device according to one embodiment of the present invention. [Figure 7] This flowchart shows the procedure for pre-fetching various map data using a map processing device according to one embodiment of the present invention. [Figure 8] This figure illustrates an overview of a first route change operation performed when a route deviation occurs, as described in a map processing device according to one embodiment of the present invention. [Figure 9]This figure shows the operation flow of a first example of route change operation when a route deviation occurs, using a map processing device according to one embodiment of the present invention. [Figure 10] This figure illustrates an overview of a second route change operation performed when a route deviation occurs, as described in a map processing device according to one embodiment of the present invention. [Figure 11] This figure shows the operation flow of a second route change operation when a route deviation occurs, according to one embodiment of the present invention of a map processing device. [Modes for carrying out the invention]

[0011] The following describes in detail, with reference to the drawings, a map processing device and a map processing method (map data pre-reading method) according to one embodiment of the present invention. The present invention is applicable, for example, to a vehicle control computing device (e.g., an MPU (Map Positioning Unit)) that can communicate with an in-vehicle ECU (Electronic Control Unit) for an Advanced Driver Assistance System (ADAS) or Autonomous Driving (AD).

[0012] [In-vehicle system configuration] Figure 1 is a schematic diagram of an in-vehicle system including a map processing device according to one embodiment of the present invention. Note that Figure 1 shows only the components related to the various processes performed by the map processing device.

[0013] As shown in Figure 1, the in-vehicle system 1 of the vehicle equipped with an autonomous driving function comprises a map processing unit 2, a car navigation system 3 (hereinafter referred to as "car navigation 3"), and an autonomous driving control unit 4, and each component is connected to the others within the in-vehicle system 1. In addition, the map processing unit 2 is connected to an external map distribution server 5, such as a cloud, via a communication network 6.

[0014] The map distribution server 5 stores various map data with high detail at the lane level required for driving support of the autonomous driving of the own vehicle (for example, lane connection data, lane attribute data, lane boundary data, etc., described below; hereinafter referred to as "high-precision map data"). The map processing device 2 acquires various high-precision map data around the own vehicle from the map distribution server 5 on demand during operation. Although not shown in the drawings, the car navigation 3 is connected via a communication network to a car navigation map distribution server provided externally such as a cloud, and acquires various road-level map data around the own vehicle from the car navigation map distribution server on demand.

[0015] The map processing device 2 has a function of pre-acquiring (hereinafter referred to as "prefetching") various high-precision map data of a recommended route to a destination required for autonomous driving support of the own vehicle (hereinafter also referred to as "scheduled travel route") and surrounding routes thereof from the map distribution server 5. As used herein, "routes surrounding the scheduled travel route" means routes that can branch from the scheduled travel route. The map processing device 2 searches for a scheduled travel route using the prefetched various high-precision map data, and outputs information related to the scheduled travel route determined by the search process to the automatic driving control device 4. Furthermore, in the present embodiment, as will be described later, when the own vehicle deviates from the scheduled travel route, the map processing device 2 also performs search and determination processing for a new scheduled travel route using the prefetched various high-precision map data. The internal configuration and processing content of the map processing device 2 will be described later with reference to the drawings.

[0016] The car navigation 3 searches for a recommended route to a destination using various road-level map data around the own vehicle acquired from the car navigation map distribution server, and sets the recommended route obtained by the search process as the scheduled travel route. The car navigation 3 also outputs various types of information such as the scheduled travel route, destination, and route search conditions set by the car navigation 3 to the map processing device 2, for example.

[0017] The automatic driving control device 4 uses information about the planned route to the destination set by the map processing device 2 or the car navigation system 3 to perform automatic driving control of the vehicle.

[0018] [Configuration of the map processing unit] Figure 2 is a diagram showing the configuration of the functional blocks of a map processing device 2 according to one embodiment of the present invention. Figure 2 shows various high-precision map processing functions of the map processing device 2. figure Only the components related to data pre-fetching and the search and determination of the planned route to the destination are shown.

[0019] As shown in Figure 2, the map processing device 2 comprises a control unit 10, a storage unit 11, a sensor unit 12, a first communication unit 13, a second communication unit 14, and a third communication unit 15. The control unit 10 is connected to the storage unit 11, the sensor unit 12, the first communication unit 13, and the second communication unit 14, while the storage unit 11 is connected to the third communication unit 15.

[0020] The control unit 10 uses various data (information) acquired from the storage unit 11, sensor unit 12, and first communication unit 13 to search for a lane-level recommended route to the destination, and outputs the information of the planned route obtained as a result of the search to the automatic driving control device 4 via the second communication unit 14. Furthermore, as will be described later, if the vehicle deviates from the planned route, the control unit 10 also performs the process of searching for and determining a new planned route. The internal configuration of the control unit 10 will be explained later.

[0021] The storage unit 11 is connected to an external map distribution server 5 via a third communication unit. The storage unit 11 stores various high-precision map data distributed from the map distribution server 5 that enables lane-level automated driving support. In this embodiment, the map distribution server 5 stores various high-precision map data that enables lane-level automated driving support not only for expressways but also for general roads.

[0022] Furthermore, the storage unit 11 includes a lane connection / attribute data storage unit 31, a lane boundary data storage unit 32, a lane shape data storage unit 33, and a lane group connection data storage unit 34.

[0023] The lane connection and attribute data storage unit 31 stores information regarding the connection relationships between lane sections that are connected to each other via branching points (e.g., intersections; hereinafter referred to as "nodes") where the physical structure changes on the driving lane (hereinafter referred to as "lane connection data"). The lane connection data includes not only connection information between lane sections (between nodes) in the direction of lane extension, but also various other information such as information regarding the position coordinates of nodes, lane identification information, driving direction, and information regarding whether lanes can be changed at nodes.

[0024] Furthermore, the lane connection / attribute data storage unit 31 stores information regarding the attributes (properties and characteristics) of each lane between nodes (hereinafter referred to as "lane attribute data"). The lane attribute data includes various information between nodes, such as lane type information, lane width, lane curvature, lane gradient type, and information indicating whether the lane is passable. The information indicating whether the lane is passable included in the lane attribute data includes real-time or time-limited traffic information, such as congestion information and construction information.

[0025] The lane boundary data storage unit 32 stores information regarding the boundaries between adjacent lanes in a direction perpendicular to the lane's extension direction (hereinafter referred to as "lane boundary data"). The lane boundary data includes information such as the type of boundary line between lanes (e.g., white line, orange line, etc.) and the type of boundary line pattern.

[0026] The lane shape data storage unit 33 stores information regarding the shape of each lane between nodes (hereinafter referred to as "lane shape data"). In this embodiment, the lane shape data includes shape data of the center line of each lane (hereinafter referred to as "lane center line shape data") and shape data of the boundary of each lane (hereinafter referred to as "lane boundary shape data"). Both the lane center line shape data and the lane boundary shape data consist of a sequence of coordinate points.

[0027] Furthermore, in the autonomous driving assistance provided by the map processing device 2, connection information of a group formed by aggregating multiple lanes existing between nodes (hereinafter referred to as "lane group") is used. In this embodiment, lane groups are also set for driving routes where the number of lanes between nodes is 1 (for example, the general roads in Figures 8 to 10 described later). That is, in this embodiment, a lane group consists of one or more lanes. The lane group connection data storage unit 34 stores information regarding the connections between lane groups that are connected to each other via nodes (hereinafter referred to as "lane group connection data"). The lane group connection data only needs to include the minimum connection information between lane groups, and in addition to the connection information between lane groups (between nodes) in the direction of lane group extension, it may include various other information such as lane group identification information.

[0028] The sensor unit 12 has various devices for recognizing structures and vehicles around the vehicle, the vehicle's position, and the vehicle's driving conditions. Specifically, the sensor unit 12 includes various devices such as a camera (camera) capable of capturing images of the surroundings of the vehicle, a GPS (Global Positioning System) module capable of measuring the vehicle's position at road level, and acceleration sensors and angular velocity sensors capable of measuring the vehicle's driving conditions. The various information acquired by the sensor unit 12 is input to the control unit 10, and the control unit 10 performs recognition processing of structures and vehicles around the vehicle and estimation processing of its own position based on this information.

[0029] The first communication unit 13 is connected to the car navigation system 3. Various information, such as the planned driving route, destination, and route search conditions set in the car navigation system 3, is transmitted to the control unit 10 via the first communication unit 13. The second communication unit 14 is connected to the automatic driving control device 4. Information on the planned driving route to the destination, determined by the control unit 10, is transmitted to the automatic driving control device 4 via the second communication unit 14. The third communication unit 15 is connected to an external map distribution server 5 via the communication network 6, receives various high-precision map data distributed from the map distribution server 5, and outputs the received high-precision map data to the storage unit 11. The operation of the first to third communication units 13 to 15 is controlled by the control unit 10.

[0030] [Configuration of the control unit] As shown in Figure 2, the control unit 10 functionally includes a surrounding recognition unit 20, a self-position estimation unit 21, a candidate path search unit 22 (path search unit), a path selection unit 23 (path determination unit), a lane data pre-reading unit 24 (map data pre-reading unit), and a map access unit 25.

[0031] The functional processing connections between each functional block are as follows: The surrounding recognition unit 20 is connected to the sensor unit 12, the self-position estimation unit 21, and the lane data pre-reading unit 24. The self-position estimation unit 21 is connected to the sensor unit 12, the candidate path search unit 22, and the lane data pre-reading unit 24. The candidate path search unit 22 is connected to the first communication unit 13, the path selection unit 23, and the lane data pre-reading unit 24. The path selection unit 23 is connected to the second communication unit 14 and the map access unit 25. The lane data pre-reading unit 24 is connected to the map access unit 25. The map access unit 25 is also connected to the lane connection / attribute data storage unit 31, the lane boundary data storage unit 32, the lane shape data storage unit 33, and the lane group connection data storage unit 34 within the storage unit 11.

[0032] The surrounding recognition unit 20 recognizes the presence and location of structures and vehicles in the area in front of the vehicle based on surrounding images of the area in front of the vehicle input from a camera (not shown) in the sensor unit 12, and various high-precision map data input from the lane data pre-reading unit 24. The surrounding recognition unit 20 then outputs the recognition results of structures and vehicles around the vehicle to the self-position estimation unit 21 and the lane data pre-reading unit 24.

[0033] The self-position estimation unit 21 estimates the vehicle's position at the lane level based on the recognition results of structures and vehicles around the vehicle input from the surrounding recognition unit 20, various sensor information input from the sensor unit 12, and various high-precision map data input from the lane data pre-reading unit 24.

[0034] In this embodiment, two types of applications are provided for estimating the vehicle's position by the self-position estimation unit 21. Specifically, one application estimates the vehicle's position using surrounding images in front of the vehicle and high-precision map data, and the other estimates the vehicle's position using high-precision map data. Hereinafter, the former application will be referred to as "high-precision locator (camera recognition)," and the latter application will be referred to as "high-precision locator (map matching)."

[0035] Furthermore, in this embodiment, the type of high-precision map data used in the vehicle position estimation process by the self-position estimation unit 21 also changes depending on the vehicle position estimation application used. Figure 3 is a diagram showing the relationship between the type of vehicle position estimation application and the type of high-precision map data used, with the high-precision map data used indicated by circles. Figure 3 also shows the high-precision map data used in the candidate route search process by the candidate route search unit 22, described later, and the planned driving route determination process by the route selection unit 23, described later (see the "Lane Level Search" column in the figure). In the figure, the high-precision map data used in the candidate route search process by the candidate route search unit 22, described later, is indicated by circles, and the high-precision map data used in the planned driving route determination process by the route selection unit 23, described later, is indicated by triangles.

[0036] The high-precision map data used in the high-precision locator (camera recognition) includes lane connection data, lane attribute data, lane boundary data, lane centerline shape data, lane boundary shape data, and lane group connection data, as shown in Figure 3. In other words, the high-precision locator (camera recognition) utilizes all types of high-precision map data stored in the memory unit 11. On the other hand, the high-precision map data used in the high-precision locator (map matching) includes lane connection data, lane attribute data, lane centerline shape data, and lane group connection data. In other words, the high-precision map data used in the high-precision locator (map matching) does not include high-precision map data related to lane boundaries.

[0037] The self-position estimation unit 21 then outputs information about the vehicle's position estimated by a high-precision locator (camera recognition) or a high-precision locator (map matching) to the candidate route search unit 22 and the lane data pre-reading unit 24.

[0038] The candidate route search unit 22 searches for candidate routes (hereinafter referred to as "candidate routes") that could be recommended routes to the set destination. In this process, the candidate route search unit 22 searches for multiple candidate routes based on the vehicle's position input from the self-position estimation unit 21, various high-precision map data input from the lane data pre-reading unit 24, and destination information (location information, etc.) input from the car navigation system 3. As will be described later, if the vehicle deviates from the pre-set planned route, the candidate route search unit 22 uses only lane group connection data as high-precision map data to perform the candidate route search process (see the circle in the "Lane Level Search" column in Figure 3). The candidate route search unit 22 then outputs information on the multiple candidate routes obtained through the search process to the route selection unit 23.

[0039] The route selection unit 23 selects (determines) a planned route from among multiple candidate routes input from the candidate route search unit 22, based on lane connection data and lane attribute data input via the map access unit 25 (see the triangle in the "Lane Level Search" column in Figure 3). In the route selection process by the route selection unit 23, candidate routes are picked up in a predetermined order from among multiple candidate routes, and a determination is made based on the lane attribute data of the picked candidate routes whether or not they are actually suitable for automated driving. If the picked candidate route is a route suitable for automated driving (a drivable route), the route selection unit 23 determines the picked candidate route as the planned route. Subsequently, the route selection unit 23 transmits information about the selected planned route ("Confirmed Route" in the figure) to the automated driving control device 4 via the second communication unit 14.

[0040] Furthermore, in the route selection process by the route selection unit 23, one order is pre-set by the driver or other personnel from among several candidate route selection orders (selection orders). (1) In order of least amount of high-precision map data loaded (2) Candidate routes in order of shortest distance (3) In order of shortest travel time to destination (4) The order in which the search conditions for the initial planned driving route set in the car navigation system 3 etc. are considered.

[0041] In the pickup order described in (1) above, since the capacity of the map data to be loaded is unknown in advance, candidate routes are picked in order of the smallest number of lane groups (nodes) to be loaded. In the pickup order described in (2) above, it is necessary to include information on the distance between lane groups (distance between nodes) in the lane group connection data. In the pickup order described in (3) above, it is necessary to include information on the average speed in the lane group connection data and to link the lane group connection data with traffic information. Furthermore, in the pickup order described in (4) above, the pickup order of candidate routes is set according to the search conditions in the car navigation system 3, such as highway usage and arrival time, which are obtained via the first communication unit 13, etc. However, in the route selection process of the planned route by the route selection unit 23, candidate routes where the distance to the next node (junction) of a lane group or lane is short and the loading of high-precision map data cannot be completed in time are excluded.

[0042] The lane data pre-reading unit 24 pre-reads (acquires) multiple types of high-precision map data of the planned driving route and / or surrounding routes ahead of the vehicle from the map distribution server 5, which is necessary for smoothly providing automated driving assistance for the vehicle. Specifically, the lane data pre-reading unit 24 selects a tile (hereinafter referred to as "map tile") from a map divided into tiles that includes the area of ​​the planned driving route and / or surrounding routes ahead of the vehicle, and pre-reads various high-precision map data of the roads included in that map tile. At this time, the type of high-precision map data to be pre-read changes according to the conditions of the pre-read target point (predetermined point) ahead of the vehicle. Specifically, for example, the type of high-precision map data to be pre-read changes according to conditions such as the distance on the driving route from the vehicle's position to the pre-read target point, whether or not the pre-read target point is on the planned driving route, and the likelihood of deviation from the planned driving route (likelihood of becoming a secondary route). The specific details of the pre-reading process by the lane data pre-reading unit 24 will be described in detail later with reference to the diagrams.

[0043] The map access unit 25 accesses the storage unit 11 to acquire various high-precision map data stored in the storage unit 11, and outputs the acquired high-precision map data to the lane data pre-reading unit 24 and the route selection unit 23. The map access unit 25 outputs high-precision map data of a type corresponding to the conditions of the pre-reading target points described above to the lane data pre-reading unit 24, and the map access unit 25 outputs lane connection data and lane attribute data of the candidate route to the route selection unit 23. As described above, in this embodiment, the route selection unit 23 determines the planned route based on the lane attribute data, so the high-precision map data input from the map access unit 25 to the route selection unit 23 may consist only of the lane attribute data of the candidate route.

[0044] [Hardware configuration of the map processing unit] The map processing device 2 of this embodiment can be composed of a computing device such as a computer device equipped with computing and communication functions. Figure 4 is a block diagram showing an example of the hardware configuration of a computing device 100 that can be applied as the map processing device 2.

[0045] The arithmetic processing unit 100 includes a CPU (Central Processing Unit) 101, ROM (Read Only Memory) 102, and RAM (Random Access Memory) 103 connected to the bus line 108. The arithmetic processing unit 100 also includes a network interface 104, an operation unit 105, a display unit 106, and non-volatile storage 107, all connected to the bus line 108. Although not shown in Figure 4, the arithmetic processing unit 100 also includes various interfaces used for inputting and outputting various data (various information) with external devices. Furthermore, although not shown in Figure 4, the arithmetic processing unit 100 also includes a component corresponding to the sensor unit 12 in Figure 2.

[0046] The CPU 101 reads the program code for the software that implements the various processing functions of the map processing device 2 from the ROM 102 into the RAM 103 and executes it. At this time, variables and parameters that arise during the calculation process are also temporarily written to the RAM 103. In other words, the control unit 10 of the map processing device 2 in Figure 2 is included in the CPU 101.

[0047] Network I / F104 is composed of, for example, a NIC (Network Interface Card) and transmits and receives various types of data between connected devices.

[0048] The operation unit 105 is composed of, for example, keys and buttons, and generates operation signals according to the operation content input by the operator and supplies these operation signals to the CPU 101. For example, the setting of the pickup order of candidate routes in the route selection process of the planned driving route by the route selection unit 23 described above can be done by operating the operation unit 105. However, such operations may also be performed via an operation unit (not shown) provided by the car navigation system 3, in which case the map processing device 2 will not have an operation unit 105.

[0049] The display unit 106 is composed of, for example, a liquid crystal panel, and displays characters, images, etc. on the screen. Alternatively, the display unit 106 may be composed of a touch panel, in which case the display unit 106 and the operation unit 105 are integrated. The output information from the map processing device 2 may be displayed on a display unit (not shown) provided for displaying various information output from, for example, a car navigation system 3, in which case the map processing device 2 does not have a display unit 106.

[0050] The non-volatile storage 107 can be composed of, for example, an HDD (Hard disk drive), an SSD (Solid State Drive), a flexible disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, magnetic tape, or non-volatile memory. The non-volatile storage 107 stores the OS (Operating System), various parameters, and a program for causing the arithmetic processing unit 100 to function as the map processing unit 2. In this embodiment, the various high-precision map data described above are stored in the non-volatile storage 107, and the storage unit 11 of the map processing unit 2 in Figure 2 is included in the non-volatile storage 107. Note that information (data) such as programs, tables, and files that realize each function of the map processing unit 2 may be stored in a recording medium other than the ROM 102 and non-volatile storage 107, for example, an IC card, an SD card, or a DVD.

[0051] [Overview of the high-precision map data pre-reading function] In this embodiment, a high-precision map data pre-reading function is provided by the lane data pre-reading unit 24, as shown in (A) to (C) below. (A) If the point to be read ahead is a point on the planned driving route, the lane data read ahead unit 24 changes the type of high-precision map data to read ahead (acquire) according to the distance on the driving route from the vehicle's position to the point to be read ahead. (B) If the point to be read ahead is a point on a surrounding route that can branch off from the planned route, the lane data read ahead unit 24 reads ahead only the lane group connection data. (C) On a route where it is possible to deviate from the planned route, the lane data pre-reading unit 24 pre-reads not only lane group connection data but also various high-precision map data necessary for automated driving support, such as lane connection data, for points within a predetermined distance from the point of deviation. In this case, the high-precision map data to be pre-read may be, for example, all types of high-precision map data as shown in Figure 3, or it may be high-precision map data other than high-precision map data relating to lane boundaries.

[0052] In this embodiment, the map processing device 2 is described as having all of the above-mentioned pre-reading functions (A) to (C), but the present invention is not limited thereto. For example, the pre-reading function (C) above (hereinafter referred to as the "deviation prediction function") may not be provided depending on the processing performance, memory capacity, etc. of the map processing device 2. Alternatively, for example, the system may be configured to have only one of the above-mentioned pre-reading functions (A) or (B). When only the pre-reading function (A) is provided, the type of high-precision map data that is pre-read at pre-reading target points on the surrounding route also changes depending on the distance on the driving route from the vehicle's position to the pre-reading target point. On the other hand, when only the pre-reading function (B) is provided, at pre-reading target points on the planned driving route, not only lane group connection data but also various high-precision map data necessary for automated driving support, such as lane connection data, are pre-read, regardless of the distance from the vehicle's position.

[0053] Here, we will explain in detail the content of the look-ahead function described in (A) above. Figure 5 is a schematic diagram showing the relationship between the type of high-precision map data read by the lane data look-ahead unit 24 and the distance on the driving route from the vehicle's position to the look-ahead point, in the look-ahead function described in (A) above (when the look-ahead target point is a point on the planned driving route). In Figure 5, a road with two lanes in each direction is used as an example. Therefore, in the example shown in Figure 5, four lanes are combined to form one lane group.

[0054] In the example shown in Figure 5, one lane group area 40, that is, one lane group section, is represented by a roughly rectangular block. Lane group connection data 41 is represented by white circular nodes (branching points) and is provided at the entry and exit points of each lane group area 40. Lane connection data 42 is represented by black circular nodes (branching points) and is provided at the entry and exit points of the corresponding lanes within each lane group area 40. Lane attribute and shape data 43 (lane attribute data and lane centerline shape data) is represented by solid lines (links) connecting the nodes of the lane connection data 42. In addition, map data 44 regarding lane boundaries (lane boundary data and lane boundary shape data) is represented by a pattern (white line pattern) in which white rectangles are placed at predetermined intervals along the direction of road extension. In addition to the white line pattern shown, the map data 44 regarding lane boundaries also includes, for example, lines indicating the boundary with the side wall and data for the side wall itself.

[0055] If the target location for pre-reading is a location 51 located at a short distance from the vehicle's position (for example, a few kilometers ahead), the lane data pre-reading unit 24 acquires various high-precision map data used in the vehicle position estimation process by the high-precision locator (camera recognition), as shown in Figure 5. Specifically, for pre-reading to a nearby location 51, the lane data pre-reading unit 24 pre-reads (acquires) lane group connection data 41, lane connection data 42, lane attribute and shape data 43, and map data 44 related to lane boundaries. In other words, for pre-reading to a nearby location 51, the lane data pre-reading unit 24 acquires all types of high-precision map data shown in Figure 3. In addition, for pre-reading to a nearby location 51, the lane data pre-reading unit 24 also acquires surrounding images in front of the vehicle taken by the camera in the sensor unit 12, thereby acquiring information about physical structures 45 and vehicles present in the area in front of the vehicle.

[0056] Figure 5 shows an example in which, when looking up a nearby point 51, the lane data lookup unit 24 looks up (acquires) not only high-precision map data for two lanes in the direction of travel of the vehicle, but also high-precision map data for two lanes in the opposite direction of travel. However, the present invention is not limited to this. When looking up a nearby point 51, for example, if there is a physical structure 45 around the area in front of the vehicle, the lane data lookup unit 24 may look up high-precision map data only for the area visible from the vehicle (for example, the area shown in the surrounding image). For example, if a median strip is provided as a physical structure 45 between the two lanes in the direction of travel of the vehicle and the opposite lane, and the opposite lane is not visible from the vehicle, the lane data lookup unit 24 may look up only high-precision map data for two lanes in the direction of travel of the vehicle. In this case, there is no need to read the high-precision map data for the opposite lane, so the amount of high-precision map data to be acquired can be further reduced.

[0057] If the target location for pre-reading is location 52, which is at a medium distance from the vehicle's current position, the lane data pre-reading unit 24 acquires various high-precision map data used in the vehicle's position estimation process by a high-precision locator (map matching). Specifically, for pre-reading to location 52 at a medium distance, the lane data pre-reading unit 24 pre-reads (acquires) lane group connection data 41, lane connection data 42, and lane attribute / shape data 43. Note that for pre-reading to location 52 at a medium distance, the lane data pre-reading unit 24 acquires only high-precision map data for two lanes in the vehicle's direction of travel.

[0058] Furthermore, if the target location for pre-reading is location 53, which is far from the vehicle's position, the lane data pre-reading unit 24 will only pre-read (acquire) the lane group connection data 41. If the target location for pre-reading is location 54, which is even farther away than location 53, the lane data pre-reading unit 24 will not pre-read (acquire) the high-precision map data. The boundary values ​​for "short distance," "medium distance," and "long distance" as described above, as well as the boundary values ​​for distances at which high-precision map data is not pre-read (the first predetermined distance D1 to the third predetermined distance D3 in Figure 7 described later), can be set appropriately according to, for example, the type of driving route (general road, expressway, etc.), the processing performance of the map processing device 2, the memory capacity, etc.

[0059] [Pre-fetching of high-precision map data by a map processing unit] Next, we will explain the processing flow of the high-precision map data pre-reading process performed by the lane data pre-reading unit 24 of the map processing device 2. The pre-reading process by the lane data pre-reading unit 24, described below, is controlled by the CPU 101 in Figure 4.

[0060] Furthermore, the lookup processing by the lane data lookup unit 24 described below will explain the lookup processing when the lookup target point is on the planned driving route and when it is on a route surrounding the planned driving route, i.e., the lookup functions described in (A) and (B) above. In addition, the deviation prediction function described in (C) above, which takes into account the possibility of deviation from the planned driving route, will be explained in detail as appropriate in the explanation of the processing flow below.

[0061] <Overall processing flow for pre-fetching high-precision map data> First, with reference to Figure 6, the overall processing flow of the high-precision map data pre-reading process performed by the lane data pre-reading unit 24 will be explained. Figure 6 is a flowchart showing the overall processing procedure of the high-precision map data pre-reading process performed by the lane data pre-reading unit 24. Note that the overall processing of the high-precision map data pre-reading process shown in Figure 6 starts when the map processing device 2 is started (powered on).

[0062] First, the lane data pre-reading unit 24 determines whether there is available time to perform the pre-reading process (S1). In this process, the lane data pre-reading unit 24 determines whether there is time for the CPU 101 to perform the map data pre-reading process, that is, whether there is sufficient processing load on the CPU 101, based on the current processing load of the CPU 101. For example, if the vehicle deviates from the planned route and processing is performed to search for a new route to the destination (for example, the operations described in Figures 8 to 11 below), the processing load on the CPU 101 for the route search process becomes high, and there is no time to perform the pre-reading process. Therefore, in such a situation, there is no available time to perform the pre-reading process, the determination process in S1 is NO, and the processing from S3 onwards (pre-reading process) described below is not performed.

[0063] In S1, if the lane data pre-reading unit 24 determines that there is no available time to perform the pre-reading process (i.e., S1 is a NO determination), the lane data pre-reading unit 24 performs a waiting process for a certain period of time (S2). After the processing in S2, the lane data pre-reading unit 24 returns to the processing in S1 and repeats the processing from S1 onward.

[0064] On the other hand, in S1, if the lane data pre-reading unit 24 determines that there is available time to perform pre-reading processing (if S1 is a YES determination), the lane data pre-reading unit 24 determines whether or not to perform pre-reading processing on the planned route (S3). In this process, if there are still points on the planned route to the destination where pre-reading processing has not been performed at this point, the lane data pre-reading unit 24 determines to perform pre-reading processing on the planned route (YES determination). On the other hand, if there are no points on the planned route to the destination where pre-reading processing has not been performed at this point, the lane data pre-reading unit 24 determines not to perform pre-reading processing on the planned route (NO determination).

[0065] In S3, if the lane data pre-reading unit 24 determines that it should perform pre-reading processing on the planned route (if S3 is a YES determination), the lane data pre-reading unit 24 acquires map tiles that include locations on the planned route where high-precision map data has not yet been acquired (S4). In other words, in this process, the lane data pre-reading unit 24 acquires map tiles that include locations on the planned route where pre-reading processing has not yet been performed.

[0066] Next, the lane data pre-reading unit 24 performs a pre-reading execution process for high-precision map data (S5). In this process, the lane data pre-reading unit 24 pre-reads (acquires) high-precision map data for each pre-read target point on the planned driving route included in the map tiles acquired in the S4 process from the map distribution server 5. At this time, as explained in Figure 5, the type of high-precision map data that the lane data pre-reading unit 24 pre-reads differs depending on the distance on the driving route from the vehicle's position to the pre-read target point. Details of the map data pre-reading execution process in S5 will be explained later with reference to Figure 7.

[0067] On the other hand, in S3, if the lane data pre-reading unit 24 determines that it does not need to perform pre-reading on the planned route (S3 is a NO determination), the lane data pre-reading unit 24 acquires map tiles that include locations on the surrounding route of the planned route where high-precision map data has not yet been acquired (S6). In other words, in this process, the lane data pre-reading unit 24 acquires map tiles that include locations on the surrounding route of the planned route where pre-reading has not yet been performed. At this time, the lane data pre-reading unit 24 acquires the map tile closest to the vehicle's position.

[0068] Next, the lane data pre-reading unit 24 performs pre-reading processing of lane group connection data (S7). In this process, the lane data pre-reading unit 24 pre-reads (acquires) lane group connection data for each pre-read target point on the surrounding route included in the map tile acquired in the processing of S6 from the map distribution server 5. If a deviation prediction function is provided, in the processing of S7, not only lane group connection data but also various high-precision map data necessary for automated driving support, such as lane connection data, are pre-read (acquired) for points on the surrounding route within a predetermined distance from the deviation point.

[0069] After processing in S5 or S7, the lane data pre-reading unit 24 determines whether to continue the high-precision map data pre-reading process (S8). In this process, the lane data pre-reading unit 24 determines whether the power to the map processing unit 2 has been turned off. If the power to the map processing unit 2 has not been turned off, the high-precision map data pre-reading process will continue, and the determination in S8 will be YES. On the other hand, if the power to the map processing unit 2 has been turned off, the determination in S7 will be NO.

[0070] In S8, if the lane data pre-reading unit 24 determines to continue the high-precision map data pre-reading process (if S8 is a YES determination), the lane data pre-reading unit 24 returns to the process in S1 and repeats the processes from S1 onward. On the other hand, in S8, if the lane data pre-reading unit 24 determines not to continue the high-precision map data pre-reading process (if S8 is a NO determination: if the power is turned off), the lane data pre-reading unit 24 terminates the high-precision map data pre-reading process.

[0071] <Processing flow for pre-fetching high-precision map data (processing S5 above)> Next, referring to Figure 7, we will explain the processing flow of the pre-fetching execution process performed in S5 of the overall processing flow of the high-precision map data pre-fetching process shown in Figure 6. Figure 7 is a flowchart showing the procedure for the high-precision map data pre-fetching execution process performed in S5 above.

[0072] First, the lane data pre-reading unit 24 determines whether the distance d from the vehicle's position to a predetermined pre-read point on the planned route included in the acquired map tile is less than a first predetermined distance D1 (S11). Here, "distance d from the vehicle's position to a predetermined pre-read point" is the distance on the planned route from the vehicle's position to the predetermined pre-read point. Also, "first predetermined distance D1" here is a threshold for determining whether the distance d from the vehicle's position to the predetermined pre-read point is short.

[0073] In S11, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is less than the first predetermined distance D1 (if S11 is a YES determination), the lane data pre-reading unit 24 performs the processing described in S14 below. On the other hand, in S11, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is not less than the first predetermined distance D1 (if S11 is a NO determination), the lane data pre-reading unit 24 determines whether the distance d from the vehicle's position to a predetermined pre-reading target point is less than the second predetermined distance D2 (S12). The "second predetermined distance D2" here is a threshold for determining whether the distance d from the vehicle's position to a predetermined pre-reading target point is a medium distance.

[0074] In S12, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is less than the second predetermined distance D2 (if S12 is a YES determination), the lane data pre-reading unit 24 performs the processing described in S15 below. On the other hand, in S12, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is not less than the second predetermined distance D2 (if S12 is a NO determination), the lane data pre-reading unit 24 determines whether the distance d from the vehicle's position to a predetermined pre-reading target point is less than the third predetermined distance D3 (S13). The "third predetermined distance D3" here is a threshold for determining whether the distance d from the vehicle's position to a predetermined pre-reading target point is a long distance.

[0075] In S13, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is less than the third predetermined distance D3 (if S13 is a YES determination), the lane data pre-reading unit 24 performs the process described in S16 below. On the other hand, in S13, if the lane data pre-reading unit 24 determines that the distance d from the vehicle's position to a predetermined pre-reading target point is not less than the third predetermined distance D3 (if S13 is a NO determination), the lane data pre-reading unit 24 performs the process described in S17 below.

[0076] Returning to the explanation of the process in S11, if S11 is determined to be YES, that is, if the distance d from the vehicle's position to the predetermined pre-read target point is short, the lane data pre-read unit 24 performs the pre-reading process for lane boundary and boundary shape data (S14). Specifically, the lane data pre-read unit 24 pre-reads (acquires) the lane boundary data and lane boundary shape data for the predetermined pre-read target point.

[0077] After processing in S14, or if S12 is determined to be YES (i.e., the distance d from the vehicle's position to the predetermined pre-read target point is a medium distance), the lane data pre-reading unit 24 performs pre-reading processing of lane connection, attribute, and centerline shape data (S15). Specifically, the lane data pre-reading unit 24 pre-reads (acquires) lane connection data, lane attribute data, and lane centerline shape data for the predetermined pre-read target point.

[0078] After processing in S15, or if S13 is determined to be YES (i.e., the distance d from the vehicle's position to the predetermined pre-read target point is long), the lane data pre-read unit 24 performs pre-reading processing of the lane group connection data for the predetermined pre-read target point (S16).

[0079] After processing in S16, or if S13 is determined to be NO, the lane data pre-reading unit 24 determines whether or not it has selected all pre-readable locations included in the acquired map tile (S17).

[0080] In S17, if the lane data prefetching unit 24 determines that all prefetch target points have not been selected (when a negative determination is made in S17), the lane data prefetching unit 24 returns the process to the processing of S11 and repeats the processing from S11 onwards. At this time, the lane data prefetching unit 24 newly selects a prefetch target point on which prefetch processing has not been performed as a predetermined prefetch target point, and repeats the processing from S11 onwards.

[0081] On the other hand, in S17, if the lane data prefetching unit 24 determines that all prefetch target points have been selected (when an affirmative determination is made in S17), the lane data prefetching unit 24 ends the prefetch execution process, and shifts the process to S8 in the prefetch processing (see FIG. 6).

[0082] As described above, in the prefetch execution process on the scheduled travel route performed by the lane data prefetching unit 24, if the distance d from the own vehicle position to the prefetch target point is a short distance (d<D1: a distance within a predetermined range), the prefetch processing of S14 to S16 is performed, and high-precision map data of all types is prefetched. In the prefetch execution process on the scheduled travel route, if the distance d from the own vehicle position to the prefetch target point is a medium distance (D1≦d<D2), the prefetch processing of S15 and S16 is performed, and high-precision map data other than data related to lane boundaries is prefetched. Further, in the prefetch execution process on the scheduled travel route, if the distance d from the own vehicle position to the prefetch target point is a long distance (D2≦d<D3: a distance within a specific range), the prefetch processing of S16 is performed, and only lane group connection data is prefetched. Note that in the prefetch execution process of the present embodiment described above, even on the scheduled travel route, if the distance d from the own vehicle position to the prefetch target point is equal to or greater than the third predetermined distance D3, the prefetch processing of S14 to S16 is not performed, and high-precision map data is not prefetched (obtained).

[0083] Route Change Operation When Route Deviation Occurs by Map Processing Device Next, we will describe the operation of changing the route to the destination (planned route) when the vehicle deviates from the planned route in the map processing device 2 of this embodiment. The operation of changing the route when the route deviates is performed by the candidate route search unit 22 and the route selection unit 23 in the map processing device 2, and this operation is controlled by the CPU 101 in Figure 4.

[0084] <Example of the first route change operation> Figure 8 shows the situation when a route deviation occurs when the vehicle enters an expressway from an ordinary road, and an overview of the first route change operation performed by the map processing device 2 when this situation occurs. The first example of route change operation considers the following route deviation situation.

[0085] First, let's assume that the planned route of the vehicle during autonomous driving, which has been set in advance by the car navigation system 3 (hereinafter referred to as "original route Ro"), is a route from the entry point INa from the general road to the expressway to the merging point A with the expressway (solid arrow in the figure). Let's also assume that before the vehicle during autonomous driving reaches the entry point INa, the driver looks at a display showing the congestion status of the expressway on the general road, or listens to the guidance voice of the car navigation system 3, and realizes that the section of the expressway from merging point A to the next merging point B is congested. Let's then consider a case where the driver decides that the original route Ro, which involves turning right at the entry point INa, is not a good idea, and takes the steering wheel abruptly (switches to manual driving) and goes straight instead of turning right at the entry point INa. If such a route deviation occurs, after the route deviation, the map processing device 2 searches for a new planned route to the destination (hereinafter referred to as "new route Rn") using the pre-read lane group connection data. In the example shown in Figure 8, after the route deviation, the return route to the expressway from entry point INb to merging point B (dashed arrow in the figure) is determined as the new route Rn.

[0086] Now, referring to Figure 9, we will explain in more detail the content of the first route change operation performed by the map processing device 2 when the route deviation situation shown in Figure 8 occurs, that is, the route return operation to the expressway. Figure 9 is a diagram showing the flow (situation) of the route change operation performed by the map processing device 2 when the route deviation situation shown in Figure 8 occurs, and the relationship between the pre-fetched high-precision map data and the acquired high-precision map data in each situation of the route change operation.

[0087] In Figure 9, as in Figure 5, a single lane group area is represented by a roughly rectangular block, lane group connection data is represented by white circular nodes (branching points), and lane connection data is represented by black circular nodes. In Figure 9, lane attribute data and lane centerline shape data are represented by links (solid lines) connecting the black circular nodes. Furthermore, in Figure 9, to simplify the explanation, the illustration of map data related to lane boundaries (lane boundary data and lane boundary shape data) is omitted. In addition, in Figure 9, to simplify the explanation, in lane group areas where lane connection data (black circular nodes) has been acquired (pre-read), the illustration of the acquired lane group connection data (white circular nodes) is omitted. Note that each lane group area shown in Figure 9 is assumed to exist within a medium distance from the vehicle (see Figure 5).

[0088] Situation (a1) in Figure 9 represents the situation before the vehicle deviates from its route. Therefore, in this situation, at least lane group connection data, lane connection data, lane attribute data, and lane centerline shape data are pre-read (acquired) in each lane group area located along the original route Ro pre-set by the car navigation system 3. In addition, in lane group areas located close to the vehicle, lane boundary data and lane boundary shape data, as well as surrounding images of the area in front of the vehicle captured by the camera in the sensor unit 12, are also acquired.

[0089] Furthermore, in situation (a1), in the lane group areas along the surrounding route of the original route Ro, mainly only lane group connection data is pre-read (acquired) (see the white circled nodes in the figure). However, at the entry point to the expressway INa, the route branches off to a different route from the original route Ro. Therefore, in situation (a1), considering the possibility of the vehicle deviating to this different route, lane connection data, lane attribute data, and lane centerline shape data are further pre-read in several lane group areas that exist along this different route from the lane group area including the entry point INa (see "Deviation Prediction" in Figure 9).

[0090] Situation (a1) is followed by Situation (b1) in Figure 9, which is the situation if the vehicle proceeds straight (deviations) instead of turning right at entry point INa, taking into account the traffic congestion on the expressway. In this case, the vehicle's map processing unit 2 (candidate route search unit 22) uses pre-read lane group connection data for each lane group area ahead of the route after the deviation to search for a new route Rn to the destination. In Situation (b1), this search process yields multiple routes as candidate routes for the new route Rn, including a return route (candidate route Rc) from entry point INb to merging point B on the expressway.

[0091] After situation (b1), the vehicle's map processing unit 2 (route selection unit 23) selects candidate routes in order of the smallest amount of high-precision map data to be read (in order of the smallest number of newly read nodes) and determines whether the candidate route is suitable for the vehicle's autonomous driving. That is, the route selection unit 23 selects candidate routes in order of the fastest possible return to the highway and determines whether the candidate route is suitable for autonomous driving. Therefore, in the example shown in Figure 9, the map processing unit 2 (route selection unit 23) first acquires lane connection data and lane attribute data for each lane group area along the candidate route Rc. This situation is situation (c1) in Figure 9. Therefore, in situation (c1), the display of acquired data in each lane group area between the entry point INb and the merging point B is represented by black circular nodes and links between nodes.

[0092] In scenario (c1), the map processing unit 2 (route selection unit 23) refers to the lane attribute data of each lane group area along the candidate route Rc to determine whether the candidate route Rc is actually suitable for autonomous driving of the vehicle (whether it is drivable or not). In the example shown in Figure 9, the map processing unit 2 (route selection unit 23) determines that the candidate route Rc is suitable for autonomous driving and selects it as the new route Rn. Subsequently, the map processing unit 2 acquires other high-precision map data sequentially on the new route Rn, starting from the lookup target points closest to the vehicle.

[0093] When a route deviation occurs as shown in Figures 8 and 9, the map processing device 2 performs a route change operation as described above. In the first example of route change operation described above, high-precision map data for each lane group area that is used or unused as the vehicle progresses is deleted (discarded) as appropriate. Furthermore, although the first example of route change operation described a case where the original route Ro before the deviation was set by the car navigation system 3, the present invention is not limited to this. For example, even if the original route Ro before the deviation was set by the map processing device 2 (control unit 10), the new route Rn is determined in the same manner as in the first example of route change operation described above.

[0094] <Example of a second route change operation> Figure 10 shows the situation when a route deviation occurs when the vehicle enters an expressway from an ordinary road, and an overview of the second route change operation performed by the map processing device 2 when the situation occurs.

[0095] The route deviation situation shown in Figure 10 is the same as that explained in Figure 8, so the explanation will be omitted here. In the example shown in Figure 10, after a route deviation, the return route from entry point INc to the expressway merging point C is determined as the new route Rn. In the example shown in Figure 10, the return route from entry point INb, which is located between entry points INa and INc, to the expressway merging point B is also a candidate route Rc1, but this candidate route Rc1 is shown as being impassable.

[0096] Here, referring to Figure 11, we will explain in more detail the second route change operation performed by the map processing device 2 when the route deviation situation shown in Figure 10 occurs, that is, the operation to return to the expressway route. Figure 11 is a diagram showing the flow (situation) of the route change operation performed by the map processing device 2 when the route deviation situation shown in Figure 10 occurs, and the relationship between the pre-fetched high-precision map data and the acquired high-precision map data in each situation of the route change operation. Note that the display modes of the lane group areas and various high-precision map data shown in Figure 11 are the same as those described in Figure 9, and each lane group area shown in Figure 11 is assumed to exist within a medium distance from the vehicle (see Figure 5).

[0097] The situation in Figure 11 (a2) is the situation before the vehicle deviates from its route. Therefore, in this situation, at least lane group connection data, lane connection data, lane attribute data, and lane centerline shape data are pre-read (acquired) in each lane group area that exists along the original route Ro pre-set by the car navigation system 3. In addition, in lane group areas that are close to the vehicle, lane boundary data and lane boundary shape data, as well as surrounding images of the area in front of the vehicle captured by the camera in the sensor unit 12, are also acquired.

[0098] Furthermore, in situation (a2), in the lane group areas along the surrounding route of the original route Ro, mainly only lane group connection data is pre-read (acquired) (see the white circled nodes in the figure). However, at the entry point to the expressway INa, the route branches off to a different route from the original route Ro. Therefore, in situation (a2), considering the possibility of the vehicle deviating to this different route, lane connection data, lane attribute data, and lane centerline shape data are further pre-read in several lane group areas that exist along this different route from the lane group area including the entry point INa (see "Deviation Prediction" in Figure 11).

[0099] Situation (a2), after the traffic congestion on the expressway, if the vehicle proceeds straight (deviations) instead of turning right at entry point INa, the situation is shown in Figure 11, which is situation (b2). In this case, the vehicle's map processing unit 2 (candidate route search unit 22) uses pre-read lane group connection data for each lane group area ahead of the route after the deviation to search for a new route Rn to the destination. In situation (b2), this search process yields multiple routes as candidate routes for the new route Rn, including a return route to the expressway from entry point INb towards merging point B (candidate route Rc1), and a return route to the expressway from entry point INc towards merging point C (candidate route Rc2).

[0100] After situation (b2), the vehicle's map processing unit 2 (route selection unit 23) selects candidate routes in order of the smallest amount of high-precision map data to be read (in order of the smallest number of nodes to be newly read), and determines whether the candidate route is suitable for the vehicle's autonomous driving. In other words, the route selection unit 23 selects candidate routes in order of the fastest possible return to the highway, and determines whether the candidate route is suitable for autonomous driving. Therefore, in the example shown in Figure 11, the map processing unit 2 (route selection unit 23) first acquires lane connection data and lane attribute data for each lane group area along the candidate route Rc1. This situation is situation (c2) in Figure 11.

[0101] In situation (c2), the map processing unit 2 (route selection unit 23) refers to the lane attribute data of each lane group area along the candidate route Rc1 to determine whether the candidate route Rc1 is actually suitable for autonomous driving (whether it is drivable or not). In the example shown in Figure 11, consider a case where the candidate route Rc1 is not suitable for autonomous driving of the vehicle due to reasons such as construction, congestion, or the lane curvature exceeding a threshold, in the middle of the driving section from entry point INb to merging point B. In this case, in situation (c2), the map processing unit 2 (route selection unit 23) determines that the candidate route Rc1 is not drivable and cannot be determined as the new route Rn (see the white X mark in the figure).

[0102] After situation (c2), the vehicle's map processing unit 2 (route selection unit 23) acquires lane connection data and lane attribute data for each lane group area along the candidate route Rc2. This situation is shown as situation (d2) in Figure 11. In situation (d2), the map processing unit 2 (route selection unit 23) refers to the lane attribute data for each lane group area along the candidate route Rc2 to determine whether the candidate route Rc2 is actually suitable for autonomous driving of the vehicle. In the example shown in Figure 11, we consider the case where the candidate route Rc2 is actually suitable for autonomous driving. In this case, in situation (d2), the map processing unit 2 (route selection unit 23) determines the candidate route Rc2 as the new route Rn. Subsequently, the map processing unit 2 acquires other high-precision map data sequentially on the new route Rn, starting from the lookup target points closest to the vehicle.

[0103] When a route deviation occurs as shown in Figures 10 and 11, the map processing device 2 performs a route change operation as described above. In the second example of route change operation described above, as the vehicle progresses, high-precision map data for each lane group area that is used or unused is deleted (discarded) as appropriate. Furthermore, although the second example of route change operation described a case where the original route Ro before the deviation was set by the car navigation system 3, the present invention is not limited to this. For example, even if the original route Ro before the deviation was set by the map processing device 2 (control unit 10), the new route Rn is determined in the same manner as in the second example of route change operation described above.

[0104] [Various effects] As described above, in the map processing device 2 of this embodiment, when pre-fetching (acquiring) high-precision map data from the map distribution server 5, the type of high-precision map data to be pre-fetched (acquired) is changed on the planned driving route according to the distance from the vehicle's position to the pre-fetch target point. For example, as described above, if the distance on the driving route from the vehicle's position to the pre-fetch target point is short, all types of high-precision map data are pre-fetched, and if it is a long distance, only lane group connection data is pre-fetched. Therefore, in the map processing device 2 of this embodiment, the capacity of high-precision map data held within the device can be reduced, thereby reducing the storage capacity required to hold map data within the device and lowering costs. Furthermore, in this embodiment, at pre-fetch target points located close to the vehicle's position, all types of high-precision map data, i.e., various high-precision map data necessary for supporting autonomous driving, etc., are pre-fetched, so the performance of the map processing device 2 is maintained. From the above, it can be seen that the map processing device 2 of this embodiment can achieve both a reduction in the storage capacity required to hold map data within the device and the maintenance of the device's performance.

[0105] In this embodiment, when the map processing device 2 pre-fetches (acquires) map data from the map distribution server 5, if the pre-fetch target point is not on the planned driving route, only the lane group connection data for that pre-fetch target point is pre-fetched. Therefore, in this embodiment, the amount of high-precision map data held within the device can be further reduced.

[0106] In the map processing device 2 of this embodiment, for points located close to the vehicle, an image of the surrounding area in front of the vehicle is acquired, and high-precision map data is not acquired for lanes that are not visible in the surrounding image. Therefore, in this embodiment, the capacity of high-precision map data to be held within the device can be further reduced.

[0107] As described above, the map processing device 2 of this embodiment is equipped with a route deviation prediction function. Specifically, if there is a branching point on the planned route where deviation is possible, the device pre-reads not only lane group connection data but also various high-precision map data necessary to support autonomous driving, such as lane connection data, for points within a predetermined distance from the branching point on the potentially deviating route (a portion of the points after the branching point). Therefore, in this embodiment, even if the driving route deviates from the planned route, various high-precision map data such as lane connection data have been pre-read for a portion of the determined new route, allowing for a quicker return to autonomous driving on the new route.

[0108] In this embodiment, when the vehicle deviates from the planned route during autonomous driving, the map processing device 2 searches for a new planned route using the lane group connection data that has been pre-read for the route after the deviation. Therefore, in this embodiment, even if the vehicle deviates from the planned route during autonomous driving, a new planned route can be quickly determined, and an early return to autonomous driving on the new planned route is also possible.

[0109] Furthermore, in the map processing device 2 of this embodiment, when multiple candidate routes are found during the route deviation search process, each candidate route is picked up in a predetermined order and it is determined whether the picked-up candidate route is drivable. In this embodiment, several types of criteria are provided as criteria for the order in which candidate routes can be picked up. Specifically, as described above, criteria for the pick-up order are provided such as the order in which the amount of high-precision map data to be read is small, the order in which the candidate route is shortest, the order in which the time required to the destination is shortest, and the order in which the search conditions for the initial planned route set in the car navigation system 3 are taken into consideration. In this embodiment, the driver or other user can select a predetermined criterion from among these criteria. Therefore, by providing such a function, it is possible to perform new route determination processing according to the user's needs and priorities.

[0110] [Various variations] In the above embodiment, an example configuration in which a car navigation system 3 is provided separately from the map processing device 2 has been described, but the present invention is not limited thereto. The car navigation system 3 may also be equipped with the various functions of the map processing device 2 described above. In this case, the car navigation system 3 functions as the map processing device 2. Alternatively, the functions of the car navigation system 3 may be provided in the map processing device 2, in which case there is no need to provide a separate car navigation system 3. Similarly, the automatic driving control device 4 may also be equipped with the various functions of the map processing device 2 described above.

[0111] In the above embodiment, an example was described in which lane connection data, lane attribute data, lane boundary data, lane centerline shape data, lane boundary shape data, and lane group connection data are separately provided as high-precision map data to be processed, but the present invention is not limited thereto. Some of these high-precision map data may be combined into a single high-precision map data, or a single high-precision map data may be divided into multiple high-precision map data. Furthermore, as high-precision map data to be processed, for example, similar map data containing the same information as the various high-precision map data described above, or related data from which the various high-precision map data described above can be derived may be used.

[0112] In the above embodiment, an example was described in which the map processing device 2 is installed in a vehicle equipped with an autonomous driving function. However, the present invention is not limited thereto, and the map processing device 2 of the above embodiment can also be applied to vehicles that are not equipped with an autonomous driving function.

[0113] Furthermore, the above-described embodiments are intended to explain the configuration of the device in detail and specifically in order to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. In addition, the present invention can take various other applications and modifications as long as they do not depart from the gist of the present invention as described in the claims. [Explanation of Symbols]

[0114] 1...In-vehicle system, 2...Map processing unit, 3...Car navigation system, 4...Automated driving control unit, 5...Map distribution server, 10...Control unit, 11...Storage unit, 12...Sensor unit, 20...Surroundings recognition unit, 21...Self-position estimation unit, 22...Candidate route search unit, 23...Route selection unit, 24...Lane data pre-reading unit, 25...Map access unit, 31...Lane connection / attribute data storage unit, 32...Lane boundary data storage unit, 33...Lane shape data storage unit, 34...Lane group connection data storage unit, 40...Lane group area, 41...Lane group connection data, 42...Lane connection data, 43...Lane attribute data, lane centerline shape data, 44...Lane boundary data, lane boundary shape data, 45...Physical structure, 51, 52, 53, 54...Pre-read target points

Claims

1. The system is capable of acquiring multiple types of map data, including lane connection data that shows connection information between lane sections in the direction of lane extension, and lane group connection data that shows connection information between lane group sections in the direction of lane group consisting of one or more lanes. When acquiring the map data for a predetermined point in front of the vehicle, the system includes a map data pre-reading unit that acquires map data of a type corresponding to the conditions of the predetermined point. The condition for the aforementioned predetermined location is whether or not the aforementioned predetermined location is a point on the vehicle's planned route. The map data pre-reading unit acquires lane connection data if the predetermined point is on the vehicle's planned route, and acquires lane group connection data if the predetermined point is on a route branching off from the vehicle's planned route. Map processing device.

2. The condition for the predetermined point is the distance from the vehicle's position to the predetermined point. The map data pre-reading unit acquires the multiple types of map data if the distance from the vehicle's position to the predetermined point is within a predetermined range, and acquires only the lane group connection data if the distance from the vehicle's position to the predetermined point is within a specific range that is further than the predetermined range. The map processing device according to claim 1.

3. The system further includes a route search unit that, when the vehicle deviates from the aforementioned planned route, searches for candidate routes that could become the new planned route by referring to the lane group connection data already acquired at points on the route the vehicle can travel after the deviation. The map processing device according to claim 1.

4. The aforementioned multiple types of map data include lane attribute data that includes information about lane characteristics and driving conditions. The route determination unit further includes, when the route search unit obtains a plurality of candidate routes, a route determination unit that sequentially selects one candidate route from the plurality of candidate routes according to a predetermined selection order, obtains the lane attribute data of the selected candidate route, and determines whether the selected candidate route is suitable for the vehicle to travel on. The map processing apparatus according to claim 3.

5. The aforementioned map data pre-reading unit acquires lane connection data for points on the route that branches off from the vehicle's planned route, and for some points after the branching point. The map processing device according to claim 1.

6. It is further equipped with a camera that captures images of the surrounding area in front of the vehicle, The aforementioned map data pre-reading unit does not acquire the map data relating to lanes that are not visible in the surrounding image. The map processing device according to claim 1.

7. A map processing device comprising a map data pre-reading unit capable of acquiring multiple types of map data, including lane connection data indicating connection information between lane sections in the direction of lane extension, and lane group connection data indicating connection information between lane group sections in the direction of lane group consisting of one or more lanes, includes acquiring map data of a type corresponding to the conditions of a predetermined point in front of the vehicle when acquiring the map data of that predetermined point. The condition for the aforementioned predetermined location is whether or not the aforementioned predetermined location is a point on the vehicle's planned route. The map data pre-reading unit acquires lane connection data if the predetermined point is on the vehicle's planned route, and acquires lane group connection data if the predetermined point is on a route branching off from the vehicle's planned route. Map processing methods.

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