JP2007155462A - Navigation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation device for setting an appropriate route for avoiding traffic obstacles by performing route search based on map data on a lower level than surrounding areas, as to an area including a position where a traffic obstacle occurs at a predetermined passage time when one's own vehicle travels there. <P>SOLUTION: Time slice calculation is used for detecting a traffic jam zone where a traffic jam, one of traffic obstacles, occurs at predetermined passage time when the own vehicle travels there (S4). An area including the jam zone is searched for (S11) based on map data on a lower level having a larger amount of information on a road network than surrounding areas in a second route search process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a navigation device that searches for a guidance route to a destination based on map data stored in a hierarchy of a plurality of levels, and in particular, a traffic obstacle occurs at a scheduled passage time when the host vehicle travels. The present invention relates to a navigation device that can set an appropriate route that avoids a traffic obstacle by searching for a route including an area based on map data at a lower level than surrounding areas.

  2. Description of the Related Art In recent years, a navigation device is often mounted on a vehicle that provides vehicle travel guidance so that a driver can easily arrive at a desired destination. Here, the navigation device detects the current position of the vehicle by a GPS receiver or the like, acquires map data corresponding to the current position through a recording medium such as a DVD-ROM or HDD or a network, and displays it on a liquid crystal monitor. It is a device that can do. Furthermore, such a navigation device has a route search function for searching for the optimum route from the vehicle position to the destination when a desired destination is input, and displays the guidance route on the display screen and approaches the intersection. In such a case, the driver is surely guided to a desired destination by providing voice guidance.

  Further, in the conventional navigation device, when searching for the above route, for example, a road type such as a highway, a toll road, a national road, a main local road, a prefectural road, a narrow street, a right / left turn prohibition, a one-way traffic, etc. Various costs are set between the links or between the links (nodes) depending on whether there is a restriction, the length of the link, that is, the length of the link, the width of the road, the number of lanes, and the like. When searching for the optimum route from the vehicle position to the destination, the route is searched from the departure side and the destination side along the link stored in the map data, and the search from the departure side is performed. In the overlapping part of the search from the destination side, a value obtained by adding the cost accumulated from the departure side and the cost accumulated from the destination side, that is, a cost addition value is calculated. As a result, a route that minimizes the calculated cost addition value is set as the guidance route.

The map data used for the route search has a hierarchical structure that is hierarchized into a plurality of levels based on the difference in the information amount of the road network. FIG. 10 is a schematic diagram showing hierarchical map data of a conventional navigation device.
The map data shown in FIG. 10 has a hierarchical structure that is hierarchized into, for example, three layers of level 1, level 2, and level 3. Level 3 is map data including national highways, exclusive roads, urban highways, and toll roads. Level 2 is map data including national and prefectural roads. Level 1 is narrow streets. This is detailed map data including other general roads, and becomes coarser map data with less information on the road network as the level increases.
And in conducting route search, in order to reduce the amount of computation related to route search, in the area near the starting point and destination, it is calculated in detail using the map data of the lower level hierarchy In the middle region of the route, a method is employed in which the calculation is roughly performed using the map data of the upper level hierarchy, and both results are integrated and output as a guide route.
Furthermore, in Japanese Patent Laid-Open No. 2002-243476, by performing a search using detailed map data of a lower level hierarchy even in an intermediate area of a route, when there is a traffic disorder such as a traffic jam, A route search and guidance device is described that can present a guidance route including a detour route based on map data to a user.
JP-A-2002-243476 (page 9, FIGS. 21 to 22)

However, in the navigation device described in Patent Document 1 described above, when a traffic fault such as a local traffic jam is found at an intermediate point based on traffic information from the traffic information center, a map of a lower level hierarchy It is supposed to search for a detour route that selects a road in the data, but if the route from the departure point to the destination is long, the vehicle will travel to the point where it is detected that a traffic obstacle has occurred In the meantime, the traffic obstacles that occurred were being resolved. Furthermore, a new traffic fault may occur while the vehicle is traveling at a point where no traffic fault has occurred during the route search. Therefore, there are many cases where it is not possible to set an optimum route for the user.
On the other hand, it is possible to restart the route search every time it is detected that the traffic obstacle has been solved or newly occurred. However, in such a search method, the processing load of the navigation device related to the route search is reduced. Was very big. In addition, when the guidance route is changed a plurality of times over time, there is a possibility that the user may be confused.

  The present invention has been made to solve the problems in the prior art, and provides a navigation device capable of setting in advance an appropriate route that avoids traffic obstacles when searching for a route. Objective.

In order to achieve the above object, the navigation device (1) according to claim 1 of the present application stores map data (23 to 25) in a hierarchy of a plurality of levels based on the information amount of the road network. ), A destination setting means (13) for setting a destination, a route searching means (13) for searching for a route to the destination set by the destination setting means based on the map data, The navigation apparatus includes a traffic obstacle detection means (13) for detecting a traffic obstacle point (66) where a traffic obstacle occurs at a scheduled passage time when the host vehicle travels, and the route search means includes the traffic obstacle Searching an area including a traffic obstacle point detected by a detection means based on lower-level map data having a larger amount of road network information than surrounding areas
Here, “traffic obstacle” refers to an event that hinders vehicle travel, such as traffic jams, speed restrictions, and closed roads.

  Further, the navigation device (1) according to claim 2 is the navigation device according to claim 1, further comprising: a traffic jam judging means (13) for judging whether or not the traffic obstacle is a traffic jam less than a predetermined distance. The route search means (13) includes a traffic fault point (66) detected by the traffic fault detection means (13) when the traffic jam judgment means judges that the traffic is less than a predetermined distance. The area is searched based on map data at a lower level than the surrounding area.

  Further, the navigation device (1) according to claim 3 includes a map data storage means (22) for storing the map data (23 to 25) in a plurality of levels based on the information amount of the road network, and a destination. A navigation apparatus comprising destination setting means (13) for setting and first route searching means (13) for searching for a route to the destination set by the destination setting means based on the map data The vehicle includes a traffic fault detection means (13) for detecting a traffic fault point where a traffic fault occurs at a scheduled passage time when the host vehicle travels, and a traffic fault point (66) detected by the traffic fault detection means. Second route search means (13) for searching again for areas based on lower-level map data having a larger amount of road network information than when the first route search means was searched. The features.

  A navigation device (1) according to claim 4 is the navigation device according to claim 3, wherein the traffic fault detection means (13) is a route searched by the first route search means (13). A point at which a traffic fault occurs at a scheduled passage time when the host vehicle travels is detected as the traffic fault point (66).

Further, the navigation device (1) according to claim 5 is the navigation device according to claim 3 or claim 4, wherein the second route search means (13) A first branch point (67, 69) located on the vehicle position side with a predetermined number of branches along the route searched by the first route search means (13) to a second branch point located on the destination side with a predetermined number of branches ( 68, 70), the area including the route up to 68, 70) is searched again based on lower-level map data than when the first route search means searches.
Here, the “branch point” corresponds to a node to which three or more links are connected, such as an interchange or an intersection.

  Further, a navigation device (1) according to claim 6 is the navigation device according to any one of claims 3 to 5, wherein a road that detects a road type of a road including the traffic obstacle point (66) is provided. The second route searching means (13) has a type detecting means (13), and the second route searching means (13) is based on the road type detected by the road type detecting means and the first branch point (67, 69) and the second branch. The number of branch points of the point (68, 70) to the traffic obstacle point is changed.

  Further, the navigation device (1) according to claim 7 is the navigation device according to any one of claims 3 to 6, wherein it is determined whether or not the traffic obstacle is a traffic jam less than a predetermined distance. A traffic judgment unit (13), and the second route search unit (13) determines that the traffic jam is less than a predetermined distance by the traffic judgment unit (13); The area including the traffic obstacle point detected by the above is searched again based on lower-level map data having a larger amount of information of the road network than when the first route search means (13) searches.

In the navigation device according to claim 1 having the above-described configuration, an area including a traffic obstacle point where a traffic obstacle occurs at a scheduled passage time when the host vehicle travels is set to a lower level where the information amount of the road network is larger than the surrounding area. Since the search is performed based on the map data, it is possible to set in advance an appropriate route that avoids traffic obstacles.
Further, since it is possible to search for a route in consideration of a traffic obstacle that occurs at the scheduled passing time of the host vehicle, it is possible to set in advance an optimum route for the user. Therefore, convenience for the user is improved, and a comfortable driving environment can be provided.

  Further, in the navigation device according to claim 2, when it is determined that the traffic obstacle is a traffic jam of less than a predetermined distance, the area including the traffic obstacle point is searched based on map data at a lower level than the surrounding area. Thus, it is possible to prevent in advance a situation in which the amount of calculation related to the route search increases due to the extremely wide search range of the lower-level map data. Therefore, it is possible to set in advance an appropriate route that avoids traffic obstacles while suppressing the amount of calculation related to the route search.

In the navigation device according to claim 3, the area including the traffic obstacle point where the traffic obstacle occurs at the scheduled passage time when the host vehicle travels on the route once searched for the information on the road network from the first search time. Since a search is performed based on a large amount of lower-level map data, it is possible to set in advance an appropriate route that avoids traffic obstacles.
Further, since it is possible to search for a route in consideration of a traffic obstacle that occurs at the scheduled passing time of the host vehicle, it is possible to set in advance an optimum route for the user. Therefore, convenience for the user is improved, and a comfortable driving environment can be provided.

  In the navigation device according to claim 4, a point where a traffic obstacle occurs at a scheduled passage time when the host vehicle travels the route once searched is detected as a traffic obstacle point. The scheduled time can be calculated more accurately. Therefore, it is possible to search for a route in consideration of a traffic obstacle that occurs at the scheduled passage time of the host vehicle.

  In the navigation device according to claim 5, the route from the first branch point located on the vehicle position side with a predetermined number of branches along the route from the traffic obstacle point to the second branch point located on the destination side with the predetermined number of branches It is possible to search by changing only the area that appropriately includes the point where the traffic fault occurred to the lower level map data because the area including the traffic is searched again based on the lower level map data from the first search. Become. Therefore, it is possible to set in advance an appropriate route that avoids traffic obstacles while suppressing the amount of calculation related to the route search.

  Further, in the navigation device according to claim 6, since the number of branch points to the traffic obstacle point at the first branch point and the second branch point is changed based on the road type, the point where the traffic obstacle occurs is appropriately included. Only the area can be specified in a range corresponding to the type of road, and an appropriate route that avoids a traffic obstacle can be set in advance while suppressing the amount of calculation related to the route search.

  Further, in the navigation device according to claim 7, when it is determined that the traffic obstacle is a traffic jam of less than a predetermined distance, an area including the traffic obstacle point is searched based on lower-level map data than at the first search time. Therefore, it can be prevented in advance that a situation in which the amount of calculation related to the route search increases due to a very wide search range using lower-level map data. Therefore, it is possible to set in advance an appropriate route that avoids traffic obstacles while suppressing the amount of calculation related to the route search.

  DETAILED DESCRIPTION Hereinafter, a navigation device according to the present invention will be described in detail with reference to the drawings based on a specific embodiment. First, a schematic configuration of the navigation device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a navigation device 1 according to this embodiment.

  As shown in FIG. 1, the navigation apparatus 1 according to the present embodiment includes a current location detection processing unit 11 that detects the current position of the vehicle, a data recording unit (map data storage unit) 12 in which various data are recorded, A navigation control unit (a destination setting unit, a route search unit, a traffic fault detection unit, a first route search unit, a second route search unit, a road type detection unit, a traffic jam, which performs various arithmetic processes based on the input information Determination means) 13, an operation unit 14 that receives an operation from the operator, a liquid crystal display 15 that displays information such as a map to the operator, a speaker 16 that outputs voice guidance about route guidance, and a traffic information center And a communication device 17 that communicates with the information center. The navigation control unit 13 is connected to a vehicle speed sensor 21 that detects the traveling speed of the vehicle.

  The components constituting the navigation device 1 will be described below. The current location detection processing unit 11 includes a GPS 31, a geomagnetic sensor 32, a distance sensor 33, a steering sensor 34, a gyro sensor 35 as an orientation detection unit, and an altimeter (not shown). And the like, and it is possible to detect the current position, direction, distance to a target (for example, an intersection), and the like.

  Specifically, the GPS 31 detects the current location and current time of the vehicle on the earth by receiving radio waves generated by artificial satellites, and the geomagnetic sensor 32 measures the direction of the vehicle by measuring the geomagnetism. The distance sensor 33 detects a distance between predetermined positions on the road. Here, as the distance sensor 33, for example, the rotational speed of a wheel (not shown) of the vehicle is measured, a sensor that detects the distance based on the measured rotational speed, the acceleration is measured, and the measured acceleration is 2 A sensor that integrates the times and detects the distance can be used.

  The steering sensor 34 detects the rudder angle of the host vehicle. Here, as the steering sensor 34, for example, an optical rotation sensor attached to a rotating portion of a steering wheel (not shown), a rotation resistance sensor, an angle sensor attached to a wheel, or the like is used.

  And the gyro sensor 35 detects the turning angle of the own vehicle. Here, as the gyro sensor 35, for example, a gas rate gyro, a vibration gyro, or the like is used. Further, by integrating the turning angle detected by the gyro sensor 35, the vehicle direction can be detected.

  Further, the data recording unit 12 reads out an external storage device and a hard disk (not shown) as a recording medium, a map information DB 22 recorded on the hard disk, a congestion degree setting table 26, a predetermined program, etc. And a recording head (not shown) which is a driver for writing data. In the present embodiment, a hard disk is used as the external storage device and storage medium of the data recording unit 12. However, in addition to the hard disk, a magnetic disk such as a flexible disk can be used as the external storage device. Also, a memory card, magnetic tape, magnetic drum, CD, MD, DVD, optical disk, MO, IC card, optical card, etc. can be used as an external storage device. Details of the map information DB 22 and the congestion level setting table 26 will be described later.

  Furthermore, the navigation control unit 13 is used as a working memory for the CPU 41 as an arithmetic device and a control device for controlling the entire navigation device 1, and when the CPU 41 performs various arithmetic processes, and when a route is searched for. In addition to the RAM 42 that stores the route data of the vehicle, a control program, the route from the current position of the vehicle to the input destination is searched in consideration of traffic obstacles occurring on the route, and set as a guide route ROM 43 in which a path setting processing program (see FIG. 5) is recorded, and an internal storage device such as a flash memory 44 in which a program read from ROM 43 is recorded. As the RAM 42, ROM 43, flash memory 44, etc., a semiconductor memory, a magnetic core or the like is used. As the arithmetic device and the control device, an MPU or the like can be used instead of the CPU 41.

  In the present embodiment, various programs are recorded in the ROM 43 and various data are recorded in the data recording unit 12. However, the programs, data, and the like are stored in the same external storage device, memory card, and the like. It is also possible to read out a program, data, etc. from the flash memory 44 and so on. Further, the program, data, etc. can be updated by exchanging a memory card or the like.

  Furthermore, the navigation control unit 13 is electrically connected to peripheral devices (actuators) of the operation unit 14, the liquid crystal display 15, the speaker 16, and the communication device 17.

  The operation unit 14 is operated when correcting the current location at the start of travel and inputting a departure point as a guidance start point and a destination point as a guidance end point. The operation unit 14 includes a plurality of operation switches (such as various keys and buttons). (Not shown). The navigation control unit 13 performs control to execute various corresponding operations based on switch signals output by pressing the switches. As the operation unit 14, a keyboard, a mouse, a barcode reader, a remote control device for remote operation, a joystick, a light pen, a stylus pen, or the like can be used. Furthermore, it can also be configured by a touch panel provided on the front surface of the liquid crystal display 15.

  The liquid crystal display 15 also has operation guidance, operation menus, key guidance, guidance route from the current location to the destination, guidance information along the guidance route, traffic information, news, weather forecast, time, mail, TV program, etc. Is displayed. Instead of the liquid crystal display 15, it is also possible to use a CRT display, a plasma display, or the like, or a hologram device that projects a hologram onto the windshield of a vehicle.

  In addition, the speaker 16 outputs voice guidance for guiding traveling along the guidance route based on an instruction from the navigation control unit 13. Here, examples of the voice guidance to be guided include “Please turn right at the intersection 200 meters ahead” and “The next national highway No. XX is congested”. In addition to the synthesized voice, the voice output from the speaker 16 can output various sound effects and various guidance information recorded in advance on a tape, a memory, or the like.

  The communication device 17 is a traffic consisting of information such as traffic jam information, regulation information, parking lot information, and traffic accident information transmitted from a traffic information center such as a VICS (registered trademark: Vehicle Information and Communication System) center. It is a beacon receiver that receives information as a radio beacon, an optical beacon, or the like via a radio beacon device, an optical beacon device, or the like disposed along a road. The communication device 17 is a network that enables communication in a communication system such as a LAN, WAN, intranet, cellular phone line network, telephone line network, public communication line network, dedicated communication line network, and communication line network such as the Internet. It may be a device. In addition to the information from the information center, the communication device 17 includes an FM receiver that receives FM multiplex information including information such as news and weather forecast as FM multiplex broadcast via an FM broadcast station. The beacon receiver and the FM receiver are unitized and arranged as a VICS receiver, but can be arranged separately.

  Next, the map information DB 22 stored in the data recording unit 12 will be described. Here, map data necessary for route guidance and map display is recorded in the map information DB 22, and the map data includes, for example, map display data for displaying a map, intersection data regarding each intersection, road (link). Link data, node data related to node points, search data for searching routes, facility data related to facilities, search data for searching points, and the like.

In the present embodiment, the map data is hierarchized into three layers according to the amount of information of the road network as shown in FIG. FIG. 2 is a schematic diagram showing map data hierarchized into three layers stored in the map information DB. In this case, for example, the level 1 hierarchy is map data divided into a plurality of 10 km square meshes, the level 2 hierarchy is a map data divided into a plurality of 20 km square meshes, and the level 3 hierarchy is This is map data divided into a plurality of 40 km square meshes.
Further, the map data of the lower level hierarchy includes a larger amount of information of the road network than the map data of the upper level hierarchy. For example, the map data of the level 3 includes the expressway national highway, the automobile exclusive road, the urban expressway, Stores information about toll roads. In addition to the road network included in level 3, the map data of level 2 stores information related to major general roads such as national roads and prefectural roads. In addition to the road network included in level 2, the level 1 map data stores detailed road network information related to all other general roads such as narrow streets.

  Furthermore, the map data mesh in the lower level hierarchy has a narrow coverage instead of having detailed data, and the map data mesh in the upper level hierarchy has a wide coverage instead of having only coarse data. ing. For example, the mesh in the lowest level (level 1) hierarchy has road data for all roads including narrow streets, but only covers the municipality range, and the mesh in the highest level (level 3) hierarchy is a highway. Only covers road data such as roads and toll roads, but covers the whole of Japan.

  It should be noted that the size of the mesh in each level of the hierarchy, that is, the level 3 hierarchy that is the uppermost layer, the level 2 hierarchy that is the intermediate layer, and the level 1 hierarchy that is the lowermost layer, that is, the range of the mesh coverage Can be determined as appropriate. Further, the number of levels constituting the map data, that is, the number of hierarchies does not necessarily have to be three layers, and may be, for example, five layers or ten layers.

  As shown in FIG. 3, the map data 23 to 25 of each level hierarchy is constituted by the map display data, intersection data, link data, node data, search data, facility data, search data, and the like described above. FIG. 3 is a diagram showing a storage area of the map information DB 22 of the navigation device 1 according to the present embodiment.

  Here, map drawing information for performing map display according to the map data 23 to 25 of each level hierarchy is stored as the map display data constituting the map data.

  The link data includes the width of the road to which the link belongs, the gradient, the cant, the bank, the road surface condition, the number of lanes of the road for each link constituting the road in the map data 23 to 25 of each level hierarchy. The data indicating the number of lanes decreasing, the width narrowing, the railroad crossing, etc. for the corner, the curvature radius, the intersection, the T-junction, the corner entrance and exit, etc. In addition to roads such as national roads, prefectural roads, narrow streets, etc., data representing uphill roads represent toll roads such as highway national roads, automobile exclusive roads, urban highways, general toll roads, toll bridges, etc. Each data is recorded. Furthermore, regarding toll roads, data relating to entrance roads (rampways), toll gates (interchanges) and the like of toll roads are recorded.

  In addition, the node data is set for each predetermined distance according to the road junction (including intersections, T-junctions, etc.) and the radius of curvature in the map data 23 to 25 of each level hierarchy. Node point coordinates (node), node attribute indicating whether the node corresponds to the intersection, etc., connection link number list that is a list of link numbers of links connected to the node, nodes adjacent to the node via the link The adjacent node number list, which is a list of node numbers, data on the height (altitude) of each node point, and the like are recorded.

Moreover, as search data, it is recorded about the data used when searching and displaying the route to the destination set in the map data 23 to 25 of each level hierarchy, and the cost when passing through the node (Hereinafter referred to as node cost) and cost data used to calculate the search cost consisting of the cost of the link constituting the road (hereinafter referred to as link cost), travel time required to pass through the link, and route search It comprises route display data for displaying the selected route on the map of the liquid crystal display 15.
Here, the node cost is basically set for the node corresponding to the intersection, and in the navigation device 1 according to the present embodiment, the presence or absence of a signal and the travel route of the own vehicle when passing through the intersection (that is, going straight) The value is determined by the type of the right turn and the left turn).
The link cost includes traffic information such as a congestion degree detected by a congestion degree setting table 26 (see FIG. 4) to be described later, in addition to the road attribute, road type, road width, number of lanes, and link length constituting the link. It is calculated using the data regarding.

  In addition, as facility data, data related to buildings such as hotels, hospitals, gas stations, parking lots, tourist facilities, interchanges, restaurants, service areas, and the like in each region are recorded together with facility IDs that identify the buildings. The map information DB 22 also records audio output data for outputting predetermined information by the speaker 16 of the navigation device 1.

Then, in the case of a route search where the distance from the current location (departure location) to the destination is a short distance (for example, about 3 km), the navigation control unit 13 is a level 1 map that is map data of the lowest layer around the current location. Search for a route using only a mesh of data.
In addition, in the case of a route search where the distance from the current location to the destination is a medium distance (for example, about 50 km), a mesh of level 1 map data that is the lowest level map data is used for the current location and the vicinity of the destination. The area adjacent to the mesh of the level 1 map data is searched for a route using the mesh of the level 2 map data which is the map data of the intermediate layer.
Furthermore, in the case of a route search where the distance from the current location to the destination is a long distance (for example, about 300 km), a mesh of level 1 map data which is the map data of the lowest layer around the current location and the destination is used. The area adjacent to the mesh of level 1 map data uses a mesh of level 2 map data which is map data of the middle layer, and the area adjacent to the mesh of level 2 map data is map data of the top layer. A route is searched using a mesh of certain level 3 map data. As a result, the amount of calculation for searching for a route can be suppressed, and the time required for the route search can be shortened.

  When the navigation control unit 13 searches for a route, the road data in the search data in the map data is examined, and a search cost (node) for roads (links and nodes) included in the mesh used for the search. Cost and link cost) to calculate the route. Specifically, the route search is performed from the departure side and the destination side, and the search cost and purpose accumulated from the departure side are overlapped in the overlap between the search from the departure side and the search from the destination side. A value obtained by adding the search costs accumulated from the ground side, that is, a cost addition value is calculated. As a result, a plurality of routes (for example, five routes) are selected in ascending order of cost, and the route with the smallest cost addition value or the route selected by the user is set as the guidance route.

  The contents of the map information DB 22 are updated by transferring information from a recording medium such as a DVD or an externally connected memory card, or by downloading information from a specific information center or the like via the communication device 17. Is done.

  Next, the congestion level setting table 26 stored in the data recording unit 12 will be described with reference to FIG. FIG. 4 is a diagram showing an example of the congestion degree setting table 26 according to the present embodiment. Here, the congestion level setting table 26 is a table in which traffic jams that affect the traveling of the host vehicle, in particular, sections and times where traffic congestion occurs are specified.

As shown in FIG. 4, the congestion degree setting table 26 according to the present embodiment includes a link number for specifying a link, a day of the week and a time zone, and a traffic jam on each day of the week and each time zone of the link specified by the link number. It is composed of the degree of congestion that specifies the degree of traffic.
Here, the degree of traffic jam is set by any one of three types of values “1”, “2”, and “3”, which means that no traffic jam occurs in that time zone on a link with “1” set. . On the other hand, a link for which “2” is set means that a traffic jam occurs in that time zone, and it takes about twice as long as usual to travel on the link. Further, a link with “3” is congested during that time period, meaning that it takes about three times as long to travel on the link.
For example, in the congestion level setting table 26 shown in FIG. 4, the congestion level is set to “2” between 8:15 and 8:30 on Monday for the link with the link number XZ1, and 8:30 to 8:45. During the period, the degree of congestion is set to “3”, and between 8:45 and 9:00, the degree of congestion is set to “2”.

And the navigation control part 13 can detect the congestion degree in each day and each time slot | zone for every link contained in the map data of each level hierarchy memorize | stored in the said map information DB22 by the congestion degree setting table 26. FIG. It becomes. As a result, as will be described later, when a link where a traffic jam occurs at a scheduled time when the host vehicle passes (that is, a link with a traffic congestion level other than “1”) is necessary to pass the link. Adjust the travel time and link cost to the value multiplied by the degree of congestion. Then, based on the adjusted travel time and link cost, a route search by time slice is performed as described later (S4 and S11 in FIG. 5).
The congestion level setting table 26 is stored in advance in the data recording unit 12 at the time of shipment of the navigation device 1, but the congestion level setting table 26 is based on information received from the traffic information center via the communication device 17. The content may be updated. In addition, the content of the congestion level setting table 26 may be updated based on the travel history of the own vehicle.

  Next, a route setting processing program executed by the CPU 41 in the navigation device 1 having the above configuration will be described with reference to FIG. FIG. 5 is a flowchart of the route guidance processing program according to the present embodiment. Here, the route guidance processing program is executed when the ignition of the vehicle is turned on, searches for the route from the current position of the vehicle to the input destination in consideration of traffic obstacles occurring on the route, and guides It is a program to set to the route. The program shown in the flowchart of FIG. 5 below is stored in the RAM 42 or ROM 43 provided in the navigation apparatus 1 and is executed by the CPU 41.

  First, in step (hereinafter abbreviated as S) 1 in the route setting processing program, the CPU 41 sets the destination based on the operation of the operation unit 14 by the user. Next, in S2, the current position of the host vehicle is detected based on the detection result of the current location detection processing unit 11. The process of S1 corresponds to the process of the destination setting unit.

  Thereafter, a route search process from the departure point that is the current position of the vehicle to the destination set in S1 (hereinafter referred to as the first route search) without considering traffic obstacles such as traffic jams, traffic closures, and speed restrictions. Process) (S3).

  The route search procedure in the first route search process of S3 will be described below with reference to FIG. FIG. 6 is a schematic diagram showing on the map the route searched by the first route search process executed by the navigation device 1 according to the present embodiment in S3. FIG. 6 shows an example in which the distance from the departure point to the destination is a long distance (for example, about 300 km) and the intermediate point is searched using the map data of the uppermost level 3 as an example. To do.

First, in the first route search process, when the navigation control unit 13 searches for a route, the road data in the search data in the map data is examined, and roads (links and nodes) included in the mesh used for the search. ) For the search cost (node cost and link cost). Then, in the overlapping part of the search from the departure side and the search from the destination side, a value obtained by adding the search cost accumulated from the departure side and the search cost accumulated from the destination side, that is, cost addition A value is calculated.
When calculating the search cost and the cost addition value, as shown in FIG. 6, meshes 51 and 65 of level 1 map data, which are the map data of the lowest layer, are respectively provided around the departure point and the destination. used. Further, the area adjacent to the level 1 map data meshes 51, 65 uses the level 2 map data meshes 52, 53, 62-64 which are the map data of the intermediate layer. In addition, the area adjacent to the level 2 map data meshes 52, 53, 62 to 64 and the area at the intermediate point thereof use the level 3 map data meshes 54 to 61 which are the highest level map data. . When the route to be searched shifts to a map of different levels of map data, the route is searched through nodes that are commonly included in different levels of map data.
As a result of the search, the route A and the route B are route candidates as shown in FIG. 6 as routes (for example, two routes in order from the smallest cost addition value) whose cost addition value satisfies a predetermined condition. Selected as. The process of S3 corresponds to the process of the first route search means.

Subsequently, in S4, a time slice calculation is performed in consideration of a traffic fault on the route searched in the first route search process of S3 (in this embodiment, only a traffic jam), and a traffic jam generating section that is a traffic fault point is generated. , Detect the degree of traffic jam.
In the following, a specific method of time slice calculation will be described. First, the CPU 41 detects the current time by the GPS 31, and further finds the route (route A and route B in FIG. 6) searched in the first route search process of S3. Based on the travel time of each link that constitutes, the estimated passing time when the vehicle travels on each link that constitutes the route is calculated. Thereafter, based on the calculated estimated passage time and the congestion level setting table 26 (see FIG. 4), whether or not a congestion occurs at the estimated passage time of each link constituting the route (specifically, the congestion level). Whether there is a link other than “1”. As a result, if it is determined that traffic congestion will occur at the scheduled passage time, the travel time of the link determined to occur is adjusted based on the traffic congestion level (specifically, the travel time multiplied by the traffic congestion level) ) Further, the estimated passage time for traveling through each link constituting the route is calculated again based on the adjusted travel time.
Thereafter, similarly, based on the estimated passage time calculated again and the congestion level setting table 26 (see FIG. 4), it is determined whether or not there is a link where a new congestion occurs at the estimated passage time of the link constituting the route. If it is determined that a traffic jam occurs, the travel time of the link determined to occur is adjusted based on the traffic jam level. The above operation is performed until a link where a new traffic jam occurs is not detected. Then, the degree of traffic congestion is detected using the traffic congestion degree setting table 26 for all links that are predicted to eventually generate traffic congestion. The process of S4 corresponds to the process of the traffic fault detection means.

  Next, in S5, whether there is a congested link on the route searched in the first route search process based on the detection result in S4, that is, the vehicle travels through each link constituting the route. At the scheduled time, it is determined whether or not there is a link for which the congestion level is set to other than “1” in the congestion level setting table 26.

As a result, when it is determined that there is a congested link on the route (S5: YES), the process proceeds to S6.
On the other hand, when it is determined that there is no traffic jam link on the route (S5: NO), it is not necessary to consider the traffic jam, so the route searched in the first route search process of S3 (route A in FIG. 6). And route B), the route with the smallest cost addition is selected as it is (S12). Thereafter, the selected route is set as a guidance route (S13), and the route guidance processing program is terminated. Then, the guidance route is displayed on the liquid crystal display 15 according to the set guidance route, and the route guidance is provided to the user by the display on the liquid crystal display 15 and the sound output from the speaker 16. In selecting the route searched in the first route search process, the route selected based on the operation of the operation unit 14 by the user may be set as the guidance route.

  Next, in S6, it is determined whether or not the length of the link determined to be congested on the route searched in the first route search process (that is, the congested section) is less than a predetermined distance (30 km in the present embodiment). Is done. Note that the process of S6 corresponds to the process of the traffic jam determination unit.

  When it is determined that the traffic jam section is less than the predetermined distance (S6: YES), the process proceeds to S7. On the other hand, if it is determined that the traffic jam section is equal to or longer than the predetermined distance (S6: NO), if the map data level of the area including the traffic jam section is lowered and searched again, the calculation amount of the CPU 41 is very large. The cost addition adjusted based on the degree of congestion detected in S4 among the routes searched in the first route search process in S3 (route A and route B in FIG. 6) (specifically Specifically, the route having the smallest link cost for the link cost of links other than “1” is selected (S12). Thereafter, the selected route is set as a guidance route (S13), and the route guidance processing program is terminated. In selecting the route searched in the first route search process, the route selected based on the operation of the operation unit 14 by the user may be set as the guidance route.

  Subsequently, in S7, the map information DB 22 determines whether or not the link determined to be congested on the route searched in the first route search process is an expressway (highway automobile national road, automobile exclusive road, city expressway, etc.). The determination is made based on the link data. Note that the process of S7 corresponds to the process of the road type detecting means.

  As a result, when it is determined that the traffic jam section is an expressway (S7: YES), the first start point located on the vehicle position (departure location) side by one branch from the traffic jam section along the route , The second branch point located on the destination side by one branch number from the traffic congestion section along the route is detected, and the lowest level including the detected first branch point and second branch point section (level 1) ) Is extracted from the map information DB 22 (S8). Here, a branch point corresponds to a node to which three or more links are connected, and corresponds to an interchange or an intersection.

  On the other hand, when it is determined that the traffic congestion section is a general road other than the expressway (S7: NO), the third position located on the vehicle position (departure location) side by two branches from the traffic congestion section along the route. The lowest level including the branching point and the fourth branching point located on the destination side by the number of two branches from the traffic jam section along the route and further including the detected third branching point and the fourth branching point The mesh of the map data of the (level 1) hierarchy is extracted from the map information DB 22 (S9).

Here, with respect to the processing of S8 and S9, a case where it is detected that a traffic jam section 66 occurs at the scheduled passage time of the route A searched in the first route search processing as shown in FIG. 6 is given as a specific example. I will explain. Here, FIG. 7 is a schematic diagram showing, in an enlarged manner, the vicinity of the traffic jam section 66 of the mesh 58 in the map on the route shown in FIG.
Here, especially when the traffic jam section 66 is an expressway, as shown in FIG. 7, the first branch start point 67 located on the vehicle position (departure location) side by the number of one branch of the traffic jam section 66, and the route A second branch start point 68 that is located on the destination side by one branch number from the traffic jam section is detected along each of the traffic jam sections, and meshes 81 to 84 of the map data at the lowest level (level 1) including that section are extracted. Is done.
If the traffic jam section 66 is a road other than an expressway, as shown in FIG. 7, a third branch start point 69 located on the vehicle position (departure location) side by the number of two branches of the traffic jam section 66, A fourth branch start point 70 located on the destination side by the number of two branches from the traffic jam section along the route is detected, respectively, and map data meshes 81 to 84 of the lowest level (level 1) layer including the section are detected. Extracted.

  Next, in S10, map data (map display data, intersection data, link data, node data, search data, facility data, search data, etc.) included in the mesh extracted in S8 or S9 is acquired from the map information DB 22. .

  Subsequently, in S11, the traffic congestion degree of each link extracted in S4 is taken into account, and the map data acquired in S10 is used to again return from the departure location that is the current position of the vehicle to the destination set in S1. Route search processing (hereinafter referred to as second route search processing).

  The route search procedure in the second route search process of S11 will be described below with reference to FIG. FIG. 8 shows the second route executed by the navigation device 1 according to the present embodiment in S11 after the route A and route B shown in FIG. 6 are searched by the first route search process and the traffic jam section 66 is detected. It is the schematic diagram which showed the path | route searched by the search process on the map.

First, in the second route search process, when the navigation control unit 13 searches for a route, the road data in the search data in the map data is examined and roads (links and nodes) included in the mesh used for the search are searched. ) Is calculated in consideration of the degree of congestion detected in S4. Further, in the second route search process, the cost calculation considering the traffic obstacle is performed by multiplying the link cost of the link detected in S4 as the section where the traffic jam occurs in the same manner.
Then, in the overlapping part of the search from the departure side and the search from the destination side, a value obtained by adding the search cost accumulated from the departure side and the search cost accumulated from the destination side, that is, cost addition A value is calculated.
When calculating the search cost and the cost addition value as described above, as shown in FIG. 8, the lowermost map in the area including the current location and the destination and the branch points 67 to 70 before and after the traffic jam section 66. Level 1 map data meshes 51, 65, 81 to 84, which are data, are used. Further, the area adjacent to the level 1 map data meshes 51, 65 uses the level 2 map data meshes 52, 53, 62-64 which are the map data of the intermediate layer. In addition, the area adjacent to the level 2 map data meshes 52, 53, 62 to 64 and the area at the intermediate point thereof use the level 3 map data meshes 54 to 61 which are the highest level map data. . When the route to be searched shifts to a map of different levels of map data, the route is searched through nodes that are commonly included in different levels of map data.
Then, as a result of the search, the route B searched in the first route search process as a route in which the cost addition value satisfies a predetermined condition (for example, two routes in order from the smallest cost addition value), and the meshes 81 to 81 A route C that bypasses the traffic jam section 66 using 84 links is newly selected as a route candidate as shown in FIG. FIG. 8 shows a case where the cost addition value of the route B and the route C is smaller than that of the route A due to the consideration of the congestion degree of the congestion section 66. When the cost addition value of A is smaller than the route B or the route C, the route A having a traffic jam section is selected as a route candidate. Note that the processing of S11 corresponds to the processing of the route search means and the second route search means.

  Thereafter, in S12, the route having the smallest cost addition value is selected from the routes searched in the second route search process in S11 (route B and route C in FIG. 8). Thereafter, the selected route is set as a guidance route (S13), and the route guidance processing program is terminated. In selecting the route searched in the first route search process, the route selected based on the operation of the operation unit 14 by the user may be set as the guidance route. Then, the guidance route is displayed on the liquid crystal display 15 according to the set guidance route, and the route guidance is provided to the user by the display on the liquid crystal display 15 and the sound output from the speaker 16. In selecting the route searched in the second route searching process, the route selected based on the operation of the operation unit 14 by the user may be set as the guidance route.

As described above in detail, the navigation device 1 according to the present embodiment detects a traffic jam section where a traffic jam, which is one of traffic obstacles, occurs at a scheduled passage time when the host vehicle travels using time slice calculation. (S4) Since the area including the traffic jam section is searched based on lower-level map data having a larger amount of road network information than the surrounding area in the second route search processing (S11), calculation related to the route search It is possible to set in advance an appropriate route that avoids traffic obstacles while suppressing the amount.
Further, in the second route search process, an area including a traffic jam section is searched based on lower-level map data having a larger amount of road network information than the first route search process performed without considering traffic obstacles (S11). Therefore, it is possible to set in advance an appropriate route that avoids a traffic obstacle while suppressing the amount of calculation related to the route search.
In addition, a point where a traffic fault occurs at the scheduled passage time when the vehicle travels on the route searched in the first route search process is detected as a traffic fault point by time slice calculation (S4). It is possible to calculate the estimated passing time of the car more accurately.
A route from the first branch point or the third branch point located on the vehicle position side to the predetermined branch number along the route from the traffic jam section to the second branch point or the fourth branch point located on the destination side with the predetermined branch number Because the search is performed again based on the lower level map data from the time of the first search, it is possible to change only the area that appropriately includes the point where the congestion section occurred to the lower level map data and search Become. Therefore, it is possible to set in advance an appropriate route that avoids traffic obstacles while suppressing the amount of calculation related to the route search.
Also, the number of branches up to the traffic congestion section at the first branch point and the second branch point when traffic jams occur on the expressway, and the third and fourth branches when traffic jams occur on general roads other than the expressway By changing each of the number of branches to a traffic jam section, it is possible to specify only an area that appropriately includes a point where a traffic fault has occurred in a range corresponding to the type of road.
In addition, only when it is determined that the length of the traffic jam section is less than the predetermined distance (S6: YES), the area including the traffic jam section is searched based on map data at a lower level than the surrounding area. It can be prevented in advance that a situation in which the amount of calculation related to the route search increases due to a very wide search range using lower-level map data.
In addition, since it is possible to search for routes that take into account traffic jams that occur at the scheduled passage time of the vehicle, it is possible to set in advance the optimal route for the user, and the route once set is changed while driving There is no fear of being done. Therefore, convenience for the user is improved, and a comfortable driving environment can be provided.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.
For example, in the present embodiment, the congestion degree setting table 26 in which the congestion degree of each link included in the map data is set is stored in the navigation device 1, but the congestion degree setting table is not in the vehicle but an external facility. It is good also as acquiring in the traffic information center, and acquiring the information regarding the congestion degree of a link when a vehicle communicates with a traffic information center.

  Here, FIG. 9 is a schematic configuration diagram showing the communication system 101 in the other embodiment. As shown in FIG. 9, the communication system 101 includes a navigation device 1, a traffic information center 102, and a network 104. The traffic information center 102 and the navigation apparatus 1 are configured to be able to transmit and receive various types of information via the network 104.

  The traffic information center 102 includes a server 111, a traffic information DB 115 as an information recording unit connected to the server 111, and a center side communication device 116. Further, the server 111 is based on an arithmetic device that performs overall control of the server 111 and a CPU 112 as a control device, a RAM 113 that is used as a working memory when the CPU 112 performs various arithmetic processes, and communication from the navigation device 1. Information related to the congestion degree of each link included in the area related to the route search of the first route search process (mesh 51 to 65 in FIG. 6) is extracted from the congestion degree setting table 117 stored in the traffic information DB 115, and navigation is performed. An internal storage device such as a ROM 114 in which various control programs for transmission to the device 1 are recorded is provided. Further, an MPU or the like can be used instead of the CPU 112.

And CPU112 transmits the information which concerns on the traffic congestion degree of each link contained in the area (mesh 51-65 in FIG. 6) relevant to the route search of a 1st route search process with respect to the navigation apparatus 1, on the other hand, Based on the information on the degree of congestion of each link transmitted from the traffic information center 102, the device 1 detects the link where the congestion occurs and the degree of congestion at the estimated passing time when the vehicle travels by time slice calculation. (S4).
Thereby, the navigation control unit 13 can detect the link where the traffic jam occurs at the scheduled passing time of the vehicle and the degree of the traffic jam.

  In the present embodiment, only the area including the branch point before and after the traffic jam section is searched for by changing to the lowest level level 1 map data. However, the area adjacent to the area including the branch point is also surrounded. It is good also as searching by changing to map data of a lower level (for example, level 2).

It is the block diagram which showed the navigation apparatus which concerns on this embodiment. It is the schematic diagram which showed the map data hierarchized by 3 layers memorize | stored in map information DB. It is the figure which showed the storage area of map information DB of the navigation apparatus which concerns on this embodiment. It is the figure shown about an example of the congestion degree setting table which concerns on this embodiment. It is a flowchart of the route guidance processing program which concerns on this embodiment. It is the schematic diagram which showed the path | route searched by the 1st path | route search process which the navigation apparatus concerning this embodiment performs at step 3 on the map. It is the schematic diagram which expanded and showed especially the congestion area vicinity among the maps on the path | route shown in FIG. After the route shown in FIG. 6 is searched by the first route search processing and a traffic jam section is detected, the route searched by the second route search processing executed by the navigation device according to the present embodiment in step 11 is displayed on the map. It is the schematic diagram shown in. It is the schematic block diagram which showed the communication system in other embodiment. It is the schematic diagram which showed the map data of the hierarchical structure which the conventional navigation apparatus has.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Navigation apparatus 11 Present location detection process part 12 Data recording part 13 Navigation control part 22 Map information DB
26 Congestion degree setting table 41 CPU
42 RAM
43 ROM
66 Traffic jam section 67 First minute starting point 68 Second minute starting point 69 Third minute starting point 70 Fourth minute starting point

Claims (7)

Map data storage means for storing map data in multiple levels based on the amount of information in the road network;
Destination setting means for setting the destination;
In a navigation device having route search means for searching a route to a destination set by the destination setting means based on the map data,
Provided with a traffic fault detection means for detecting a traffic fault point where a traffic fault occurs at the scheduled passing time when the host vehicle travels,
The route searching means searches for an area including the traffic obstacle point detected by the traffic obstacle detecting means based on lower-level map data having a larger amount of road network information than the surrounding area. . A traffic judgment means for judging whether the traffic obstacle is a traffic jam less than a predetermined distance;
When the route search means determines that the traffic jam is less than a predetermined distance by the traffic jam judgment means, the area including the traffic fault point detected by the traffic fault detection means is converted into map data at a lower level than the surrounding area. The navigation device according to claim 1, wherein the search is performed based on the search. Map data storage means for storing map data in multiple levels based on the amount of information in the road network;
Destination setting means for setting the destination;
A navigation device comprising: first route search means for searching a route to the destination set by the destination setting means based on the map data;
A traffic fault detection means for detecting a traffic fault point where a traffic fault occurs at a scheduled passage time when the host vehicle travels;
Second route search means for searching again an area including the traffic obstacle point detected by the traffic obstacle detection means based on lower-level map data having a larger amount of information of the road network than when the first route search means is searched; A navigation device comprising:   The traffic obstacle detection unit detects, as the traffic obstacle point, a point where a traffic obstacle occurs at a scheduled passage time when the vehicle travels on the route searched by the first route searching unit. Item 4. The navigation device according to Item 3.   The second route search means is located on the destination side of the predetermined number of branches from the first branch point located on the vehicle position side of the predetermined number of branches along the route searched by the first route search means from the traffic obstacle point. 5. The navigation device according to claim 3, wherein an area including a route to the second branch point is searched again based on lower-level map data than when the first route search means searches. . Road type detecting means for detecting the road type of the road including the traffic obstacle point;
The second route search means changes the number of branch points from the first branch point and the second branch point to the traffic obstacle point based on the road type detected by the road type detection means. The navigation device according to any one of claims 3 to 5. A traffic judgment means for judging whether the traffic obstacle is a traffic jam less than a predetermined distance;
The second route search means searches the first route search means for an area including the traffic fault point detected by the traffic fault detection means when the traffic jam judgment means determines that the traffic is less than a predetermined distance. The navigation device according to any one of claims 3 to 6, wherein the search is performed again based on lower-level map data having a larger amount of information on the road network than the time.

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