JP2012037382A - Route search device, route search method and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route search device, a route search method and a computer program which can reduce communication processing, communication time, communication costs and the like concerning communication with a center.SOLUTION: A route search device is configured to perform route searching by: acquiring basic congestion information from a VICS center 5 (S2); performing first route search processing for searching a route to a destination based on the acquired basic congestion information (S3); performing second route search processing for searching a route from a departure place to the destination by assuming that links other than a specific link in links included in a first travel route are congested and also links other than the specific link in links not included in the first travel route are non-congested (S4); and acquiring additional congestion information as center traffic information from a probe center 4 when it is determined that the first travel route and a second travel route do not match (S6).

Description

  The present invention relates to a route search device, a route search method, and a computer program for searching for a route from a departure place to a set destination.

  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. Further, such a navigation device has a route search function for searching for an optimum route from a departure point (for example, the current position of the vehicle) to a set destination when a desired destination is set. A guide route is displayed, and when the vehicle approaches an intersection, the driver is surely guided to a desired destination by voice guidance. In recent years, some mobile phones, PDAs (Personal Digital Assistants), personal computers, and the like have functions similar to those of the navigation device.

  In the navigation device or the like, when searching for an optimum route from a departure place to a set destination, consideration is given to road congestion. Specifically, to avoid congested roads and preferentially travel on free roads, for example, increase search costs for congested roads and lower search costs for free roads. The route search is performed.

  Here, as a means for the navigation device or the like to acquire the traffic information related to the traffic on the road, a means for acquiring the traffic information supplied from the road traffic information communication system (VICS: registered trademark) or a center for distributing the center traffic information There is means for acquiring traffic jam information as center traffic information from a probe center (for example, a probe center).

  The VICS detects a vehicle traveling on the road by a sensor installed on the road, and the information collection center (hereinafter referred to as VICS center) collects the detection results to obtain traffic information (hereinafter referred to as VICS information). ) And provide it to a terminal such as a car navigation device. However, the above-mentioned VICS can only create VICS information for only the main road where the sensor is installed, and there is a problem that the range of target roads for which information is provided is narrow.

  On the other hand, the probe center that distributes center traffic information is not limited in the information collection range as in the VICS, and has an advantage that data can be collected in real time from a very wide range.

  Therefore, conventionally, it has been proposed to use the traffic information supplied from the VICS in combination with the traffic information acquired from the probe center or the like. For example, in Japanese Patent Laid-Open No. 2003-149556, first, it is determined whether there is a traffic jam section on the guide route based on the traffic jam information supplied from the VICS, and when it is determined that there is a traffic jam section on the guide route. It has been proposed to obtain more detailed traffic information from the probe center.

Japanese Patent Laying-Open No. 2003-149556 (page 3, FIG. 3)

  Here, the process of acquiring the center traffic information from the probe center or the like that distributes the center traffic information has a large amount of communication data transmitted and received between the center and the vehicle. Increased communication costs were a problem. Moreover, even when traffic jam information is acquired as center traffic information from a probe center or the like and a route search is performed, the result is the same as when a route search is performed based only on the traffic jam information acquired from VICS. May be searched. Even in such a case, when the center traffic information is acquired from the probe center or the like as in Patent Document 1, communication processing, communication time, communication cost, and the like may be wasted as a result.

  The present invention has been made to solve the above-described conventional problems, and as a result of acquiring the center traffic information from the center, it is appropriately determined when there is a possibility that a different route becomes a recommended route to the destination. As a result, it is possible to reduce communication with the center, which is unnecessary as a result, and to reduce the communication processing with the center, communication time, communication cost, etc., It is an object to provide a route search method and a computer program.

  In order to achieve the above object, the route search device (1) according to claim 1 of the present application acquires basic traffic jam information that is traffic jam information of a specific link without going through the center (4) that distributes the center traffic information. Using the basic traffic information acquired by the information acquisition unit (41), the destination setting unit (42) for setting the destination, and the basic traffic information acquisition unit, the destination setting unit sets the destination from the departure point. First route searching means (43) for searching for a route to the destination and specifying the first travel route based on the search result, and links other than the specific link among the links included in the first travel route The destination set by the destination setting means from the departure point on the assumption that there is a link other than the specific link among the links not included in the first travel route. The second route search means (44) for searching for a route at and specifying the second travel route based on the search result, and determining whether or not the first travel route and the second travel route match. When it is determined that the route coincidence determining means (45) does not match the first travel route and the second travel route, the traffic congestion of the link including the link other than the specific link as the center traffic information from the center. The destination set by the destination setting means from the departure point using the additional traffic information acquisition means (46) for acquiring additional traffic information as information and the additional traffic information acquired by the additional traffic information acquisition means And third route searching means (47) for searching for a route up to.

  Further, the route search device (1) according to claim 2 is the route search device according to claim 1, wherein the basic traffic jam information acquisition means (41) is traffic jam information supplied from a road traffic information communication system. Is acquired as the basic traffic jam information, and the additional traffic jam information acquisition means (46) acquires the traffic jam information collected and probed as the probe information as the basic traffic jam information.

  Further, the route search device (1) according to claim 3 includes basic traffic information acquisition means (41) for acquiring basic traffic information that is traffic information of a specific link from outside, and a link including links other than the specific link. Using the basic traffic information acquired by the storage means for storing additional traffic information that is traffic information, the destination setting means (42) for setting the destination, and the basic traffic information acquisition means, the destination from the departure location. Search for a route to the destination set by the location setting means, and specify a first travel route based on the search result, and among the links included in the first travel route, Assuming that a link other than the specific link is congested, and assuming that a link other than the specific link among the links not included in the first travel route is vacant, the destination setting means from the departure point The second route search means (44) for searching the route to the set destination and specifying the second travel route based on the search result matches the first travel route and the second travel route. A route coincidence determining means (45) for determining whether or not the additional traffic congestion information is acquired from the storage means when it is determined that the first travel route and the second travel route do not match. Information acquisition means (46) and third route search means for searching for a route from a departure place to the destination set by the destination setting means using the additional traffic jam information acquired by the additional traffic jam information acquisition means (47).

  Further, the route search device (1) according to claim 4 is the route search device according to claim 3, wherein the basic traffic jam information acquisition means (41) is traffic jam information supplied from a road traffic information communication system. Is acquired as the basic traffic jam information, and the additional traffic jam information acquisition unit (46) acquires the traffic jam information stored in the storage unit as the additional traffic jam information.

  The route search method according to claim 5 is a basic traffic jam information acquisition step for acquiring basic traffic jam information as traffic jam information of a specific link without going through the center (4) that distributes the center traffic information, and sets a destination. Using the basic traffic information acquired at the destination setting step and the basic traffic information acquisition step, a route from the departure point to the destination set by the destination setting step is searched, and based on the search result It is assumed that a link other than the specific link is congested among the links included in the first travel route and the first route search step for identifying the first travel route, and is not included in the first travel route. Searching for a route from the starting point to the destination set by the destination setting step on the assumption that links other than the specific link are vacant, and the search result A second route search step that identifies a second travel route based on the route, a route match determination step that determines whether the first travel route and the second travel route match, the first travel route, When it is determined that the second travel route does not match, an additional traffic information acquisition step of acquiring additional traffic information that is traffic information of a link including a link other than the specific link as the center traffic information from the center; A third route search step for searching for a route from a departure place to a destination set by the destination setting step using the additional traffic jam information acquired by the additional traffic jam information acquisition step. To do.

  Further, a computer program according to claim 6 is installed in a computer and has a basic traffic information acquisition function for acquiring basic traffic information which is traffic information of a specific link without going through the center (4) for distributing center traffic information, Using the destination setting function for setting a destination and the basic traffic information acquired by the basic traffic information acquisition function, a route from the departure point to the destination set by the destination setting function is searched and searched. It is assumed that the first route search function for identifying the first travel route based on the result and the links other than the specific link among the links included in the first travel route are congested. Assuming that links other than the specific link among the links not included in the link are vacant, the route from the starting point to the destination set by the destination setting function is searched. A second route search function for specifying a second travel route based on a search result, a route match determination function for determining whether or not the first travel route and the second travel route match, and the first travel When it is determined that the route and the second travel route do not coincide with each other, additional traffic information acquisition that acquires additional traffic information as link traffic information including links other than the specific link as the center traffic information from the center And a third route search function for searching for a route from the departure point to the destination set by the destination setting function using the additional traffic jam information acquired by the additional traffic jam information acquisition function. It is characterized by that.

  According to the route search device according to claim 1 having the above configuration, as a result of acquiring the center traffic information from the center, different routes become recommended routes to the destination (that is, the first travel route and the third travel route). Can be appropriately determined. Therefore, communication with the center which becomes unnecessary as a result can be reduced in advance, and communication processing with the center, communication time, communication cost, and the like can be reduced.

  In addition, according to the route search device according to claim 2, an appropriate route search is performed using the traffic jam information supplied from the road traffic information communication system and the traffic jam information collected and statistically collected as probe information at the center. While making it possible to execute processing, communication processing with the center, communication time, communication cost, and the like can be reduced.

  Further, according to the route search device according to claim 3, when the route search device searches for a route alone, as a result of acquiring traffic jam information from the storage means, a different route becomes a recommended route to the destination (ie, It is possible to appropriately determine a case where there is a possibility that the first travel route and the third travel route are different. Accordingly, it becomes possible to reduce the reading of traffic information stored in the storage means that is unnecessary as a result, reducing the processing load on the CPU related to the reading of the traffic information stored in the storage means and the search time. Can be achieved.

  In addition, according to the route search device of the fourth aspect, the appropriate route search process is executed using the traffic jam information supplied from the road traffic information communication system and the traffic jam information stored in the storage means. In addition, it is possible to reduce the processing load on the CPU and the search time for reading traffic information stored in the storage means.

  According to the route search method of claim 5, as a result of acquiring the center traffic information from the center, a different route becomes a recommended route to the destination (that is, the first travel route and the third travel route are different). ) It is possible to appropriately determine when there is a possibility. Therefore, communication with the center which becomes unnecessary as a result can be reduced in advance, and communication processing with the center, communication time, communication cost, and the like can be reduced.

  Further, according to the computer program of the sixth aspect, as a result of acquiring the center traffic information from the center, a different route becomes a recommended route to the destination (that is, the first travel route and the third travel route are different). Appropriate determinations can be made for possible cases. Therefore, communication with the center which becomes unnecessary as a result can be reduced in advance, and communication processing with the center, communication time, communication cost, and the like can be reduced.

1 is a schematic configuration diagram illustrating a route search system according to the present embodiment. It is the block diagram which showed the structure of the route search system which concerns on this embodiment. It is the figure which showed an example of the criteria for judging the degree of traffic jam. It is the figure which showed an example of center traffic information. It is the figure which showed an example of VICS information. It is a block diagram which shows typically the control system of the navigation apparatus which concerns on this embodiment. It is the figure which showed the structure of navigation ECU. It is a flowchart of the route search processing program concerning this embodiment. It is the figure which showed the example judged with it being necessary to acquire center traffic information from a probe center. It is the figure which showed the example determined that it is not necessary to acquire center traffic information from a probe center.

  Hereinafter, a route search device according to the present invention will be described in detail with reference to the drawings based on an embodiment embodied in a navigation device. First, a schematic configuration of a route search system 2 including the navigation device 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram showing a route search system 2 according to the present embodiment. FIG. 2 is a block diagram showing the configuration of the route search system 2 according to this embodiment.

  As shown in FIG. 1, the route search system 2 according to the present embodiment collects probe information from each vehicle 3 equipped with the navigation device 1 and each vehicle 3 and creates traffic information based on the collected probe information. It is basically composed of a probe center 4 that performs distribution and a VICS center 5 that generates and distributes road traffic information communication system (VICS: registered trademark) information.

  The vehicle 3 is a vehicle that travels on roads throughout the country, and constitutes a probe car system together with a probe center 4 described later as a probe car. Here, the probe car system is a system that collects information using a vehicle as a sensor. Specifically, the vehicle probes the current position, vehicle speed, operating status of each system such as steering operation and shift position, etc. via the vehicle communication module 6 such as a mobile phone mounted in the vehicle in advance. A system that transmits to the center 4 and reuses the collected data as various information on the center side.

  In addition, the probe center 4 collects and accumulates probe information including the current time and travel information transmitted from each vehicle 3 traveling all over the country, and traffic information such as traffic jam information from the accumulated probe information. It is a traffic information distribution center that generates and distributes the generated traffic information to the vehicle 3 as center traffic information. The probe center 4 also acquires VICS information from the VICS center 5 via a dedicated line, and distributes it to the vehicle 3 as center traffic information together with traffic information generated based on the probe information as necessary.

  Here, as the probe information acquired by the vehicle 3 and transmitted to the probe center 4 in the route search system 2 according to the present embodiment, the link number of the link on which the vehicle 3 travels and the link travels. Contains information about vehicle speed. The probe center 4 calculates the average vehicle speed of the vehicle for each link based on the link number and the vehicle speed transmitted from the vehicle 3, and based on threshold values (for example, 10km and 20km for general roads) as described later. To detect the degree of traffic on each link. Then, the detected congestion degree of each link is distributed to the vehicle 3 as center traffic information.

  On the other hand, the VICS center 5 uses a sensor installed on the road to collect the detection results obtained by detecting the vehicle 3 traveling on the road, information provided by a specific organization (for example, the National Police Agency), and the like. This is an information providing center that generates VICS information that is traffic information based on detection results and provided information, and provides the generated VICS information to the vehicle 3 by FM multiplex broadcasting, optical beacons, radio beacons, or the like. The VICS information is also provided to the probe center 4 via a dedicated line. The provided VICS information includes regulation information, parking lot information, service area information, parking area information, and the like, in addition to traffic jam information (traffic congestion level and traffic jam length). When generating the traffic congestion level, the average vehicle speed of the vehicle for each link is calculated as in the probe center 4, and the traffic congestion level of each link is detected based on the threshold value. Note that other methods may be used as a method of detecting the degree of congestion by the VICS center 5. For example, the detection may be performed using the number or density of vehicles traveling on the road.

  A navigation device 1 is installed in the vehicle 3. The navigation device 1 is an in-vehicle device that displays a map around the vehicle position based on stored map data, and searches and guides a route to a set destination. The navigation device 1 also guides the center traffic information received from the probe center 4 and the VICS information received from the VICS center 5 to the user. Further, when searching for a route, the route is searched using the traffic information included in the center traffic information received from the probe center 4 and the VICS information received from the VICS center 5. The details of the navigation device 1 will be described later.

  Next, the probe center 4 will be described in more detail with reference to FIG. As shown in FIG. 2, the probe center 4 basically includes a server 11, a probe information DB 12 as information recording means connected to the server 11, a traffic information DB 13, and a center communication device 14.

  The server 11 is a control device that controls the entire probe center 4 and includes a CPU, a RAM, a ROM, and the like. Then, the traffic information to be distributed to the vehicle 3 is generated by statistically processing the probe information collected from the vehicle 3 to create a traffic level calculation process for detecting the traffic level for each link and various traffic information including the link traffic level. Perform distribution processing.

  The probe information DB 12 is a storage unit that cumulatively stores probe information collected from each vehicle 3 traveling throughout the country. In the present embodiment, the probe information collected from the vehicle 3 includes, in particular, a link number that identifies a link on which the vehicle 3 has traveled and information on the vehicle speed of the vehicle 3 that travels on that link.

  In addition, the traffic information DB 13 is a storage unit that stores center traffic information such as traffic information generated by the server 11 based on statistical processing on the probe information stored in the probe information DB 12 and VICS information transmitted from the VICS center 5. It is. Here, the center traffic information stored in the traffic information DB 13 includes a degree of link congestion, a link travel time, an average vehicle speed, and the like. The congestion level is a type of congestion information that indicates the level of congestion. From the higher congestion level, traffic congestion, congestion, empty, and unknown There are four levels of data. The degree of congestion is determined based on the average vehicle speed of the link and the threshold value. Here, FIG. 3 is a diagram illustrating an example of a criterion for determining the degree of congestion.

As shown in FIG. 3, different values are set for the threshold for determining the degree of congestion depending on road attributes (three types of “intercity highway”, “city highway”, and “general road”). Specifically, in the “intercity highway”, the threshold of “congestion” and “congestion” is 40 km / h, and the threshold of “congestion” and “empty” is 60 km / h. In the “urban expressway”, the threshold for “congestion” and “congestion” is 20 km / h, and the threshold for “congestion” and “empty” is 40 km / h. Further, in the “general road”, the threshold for “congestion” and “crowded” is 10 km / h, and the threshold for “crowded” and “empty” is 20 km / h. If probe data for determining the degree of traffic is insufficient, it is determined as “unknown”.
Therefore, for example, the server 11 determines that the degree of congestion is “congested” for a link where it is detected that the vehicle is traveling on an ordinary road at an average speed of 15 km / h. The threshold shown in FIG. 3 may be set to a different value for each area (secondary mesh unit or prefecture unit).

Next, the center traffic information stored in the traffic information DB 13 will be described in more detail with reference to FIG. FIG. 4 is a diagram showing an example of center traffic information stored in the traffic information DB 13.
As shown in FIG. 4, the center traffic information includes a link number for identifying a link, a degree of traffic congestion, a link travel time indicating an average required time of a vehicle traveling on the link, and an average vehicle speed of the vehicle traveling on the link. Composed. For example, the center traffic information shown in FIG. 4 indicates that for the link with the link number “1000”, the congestion degree is “congested”, the link travel time is 28 sec, and the average vehicle speed is 17 km / h. The traffic information DB 13 stores the above-mentioned center traffic information for the number of links constituting the map data of the navigation device 1. Further, the center traffic information includes VICS information acquired from the VICS center 5. For example, the center traffic information may be created by applying the congestion level based on the VICS information for the link for which the probe data for determining the congestion level is insufficient. Also, the center traffic information may be created by preferentially applying the traffic congestion level based on the VICS information to the link where the probe data for determining the traffic congestion level is satisfied.

  Then, when there is a delivery request from the vehicle 3, the probe center 4 delivers the center traffic information stored in the traffic information DB 13 to the requested vehicle 3. The center traffic information to be distributed is information relating to the vicinity of the departure point (or home), the destination, and the guidance route currently set for the vehicle 3 to be distributed. However, in this embodiment, particularly when the traffic information is distributed as the center traffic information, the traffic information regarding the link specified as “unknown” is not transmitted, and “congested”, “congested”, and “empty” are transmitted. Only send traffic information about links identified in.

  The link number used in the probe data and the center traffic information is an identification number used only between the probe center 4 and the navigation device 1 of the vehicle 3, and is a link number (VICS) used in the VICS center 5 or the VICS information. Different from the link number). Further, the link classification is also different between the probe data and the center traffic information, and the VICS center 5 and the VICS information.

  The center communication device 14 is a communication device for communicating with the vehicle 3 or the VICS center 5 via the network 15.

  Next, the VICS center 5 will be described with reference to FIG. As shown in FIG. 2, the VICS center 5 includes a VICS information DB 16 that stores VICS information and a VICS communication device 17.

  The VICS information DB 16 is a storage for storing VICS information, which is traffic information generated based on vehicle detection results by sensors installed on the road surface or information provided from a specific organization (for example, the National Police Agency). Means. The VICS center 5 extracts necessary information from the VICS information stored in the VICS information DB 16 every predetermined time (for example, every 5 minutes), and distributes it to the navigation device 1 via the VICS communication device 17.

  Here, when the traffic congestion information is created as the VICS information in the VICS center 5, the average vehicle speed of the vehicle is calculated based on the detection result of the vehicle by the sensor, and the average vehicle speed and the threshold value are used similarly to the probe center 4. Judgment is made (see FIG. 3). However, the VICS center 5 does not determine the degree of congestion as “unknown”. In addition, it is possible to determine the degree of traffic jam for each section of the road, not for each link. Further, the degree of congestion may be determined by setting a threshold different from that of the probe center 4.

  The VICS communication device 17 is a communication device that distributes VICS information to the navigation device 1 by FM multiplex broadcasting, optical beacons, radio beacons, or the like. And the navigation apparatus 1 receives the VICS information regarding the prefecture where a vehicle is located, and a neighboring prefecture via FM multiplex broadcasting. Further, during traveling on a highway where a radio beacon is installed, VICS information relating to the highway around the current position of the vehicle (for example, within 200 km) is further received via the radio beacon. Further, during traveling on a main general road where an optical beacon is installed, VICS information relating to the main general road around the current position of the vehicle (for example, within 30 km) is further received via the optical beacon. The VICS information is also distributed to the probe center 4 via a dedicated communication line. Note that VICS information for all areas is distributed to the probe center 4. The VICS information distributed to the navigation device 1 and the probe center 4 includes restriction information, parking lot information, service area information, parking area information, and the like in addition to traffic jam information. Traffic jam information is created only for major roads where sensors are installed.

Hereinafter, the VICS information stored in the VICS information DB 16 will be described in more detail with reference to FIG. FIG. 5 is a diagram showing an example of VICS information stored in the VICS information DB 16.
As shown in FIG. 5, the VICS information is composed of a VICS link number for identifying a link and detailed information indicating a traffic congestion degree, a traffic congestion length indicating a traffic congestion section, accident information, construction information, and the like. . For example, the VICS information shown in FIG. 5 is information that is generated for 5 minutes from 13:56 to 14: 1 on August 6, 2010, and is distributed at 14: 1. The VICS link number “533945- The link “4-4” indicates that the congestion degree is “congestion” in all sections. Further, it is shown that the vehicle regulation is performed by the construction between 13:00 and 18:00 for the link of the VICS link number “533946-10-2”. Further, it is indicated that the congestion degree is “congested” in all sections for the link having the VICS link number “533947-6-1”. When only a part of the link is a traffic jam, the VICS information also includes information on the coordinates of the traffic jam start point and information on the distance of the traffic jam section from the traffic start point.

  Next, a schematic configuration of the navigation device 1 mounted on the vehicle 3 will be described with reference to FIG. FIG. 6 is a block diagram schematically showing a control system of the navigation device 1 according to the present embodiment.

  As shown in FIG. 6, the navigation device 1 according to this embodiment includes a current position detection unit 21 that detects a current position of a vehicle on which the navigation device 1 is mounted, a data recording unit 22 that records various data, Based on the input information, the navigation ECU 23 that performs various arithmetic processes, the operation unit 24 that receives operations from the user, the liquid crystal display 25 that displays a guide route to the map and the destination for the user, and the route A speaker 26 that outputs voice guidance related to guidance, a DVD drive 27 that reads a DVD that is a storage medium storing a program, and a communication module 6 that communicates with the probe center 4, the VICS center 5, and the like. ing.

Below, each component which comprises the navigation apparatus 1 is demonstrated in order.
The current position detection unit 21 includes a GPS 31, a vehicle speed sensor 32, a steering sensor 33, a gyro sensor 34, and the like, and can detect the current vehicle position, direction, vehicle traveling speed, current time, and the like. . Here, in particular, the vehicle speed sensor 32 is a sensor for detecting a moving distance and a vehicle speed of the vehicle, generates a pulse according to the rotation of the driving wheel of the vehicle, and outputs a pulse signal to the navigation ECU 23. The navigation ECU 23 counts the generated pulses to calculate the rotational speed and moving distance of the drive wheels. Note that the navigation device 1 does not have to include all of the above five types of sensors, and the navigation device 1 may include only one or more of these types of sensors.

  The data recording unit 22 reads an external storage device and a hard disk (not shown) as a recording medium, a map information DB 35, a distribution information DB 36, a predetermined program, and the like recorded on the hard disk, and stores predetermined data on the hard disk. And a recording head (not shown) as a driver for writing. The data recording unit 22 may be constituted by a memory card instead of the hard disk.

  Here, for example, the map information DB 35 searches for link data relating to roads (links), node data relating to node points, facility data relating to facilities, map display data for displaying a map, intersection data relating to each intersection, and routes. Search means, search data for searching points, and the like are stored.

Search data is data used when searching and displaying a route to a set destination, and costs for passing through a node (hereinafter referred to as node costs) and costs for links constituting a road. Cost data used for calculating a search cost (hereinafter referred to as a link cost), route display data for displaying a route selected by the route search on a map of the liquid crystal display 25, and the like.
Here, the node cost is basically set for the node corresponding to the intersection. For example, the node cost depends on the presence or absence of a traffic light or the travel route of the vehicle when passing through the intersection (that is, the type of straight turn, right turn, and left turn). The value is determined.
The link cost is determined based on the link length. Further, the link cost is increased or decreased depending on the road type, road width, number of lanes, and degree of congestion.

  The distribution information DB 36 is storage means for storing center traffic information (FIG. 4) distributed from the probe center 4 and VICS information (FIG. 5) distributed from the VICS center 5. And navigation ECU23 performs a route search process using the center traffic information and VICS information memorize | stored in distribution information DB36.

  On the other hand, the navigation ECU (Electronic Control Unit) 23 obtains basic traffic information acquisition means 41 for acquiring basic traffic information as traffic information of a specific link from the VICS center 5 without going through the probe center 4 as shown in FIG. Destination setting means 42 for setting a destination, first route searching means 43 for searching for a route from the departure point to the destination using basic traffic jam information, and identifying a first travel route based on the search result; Among links included in one travel route, links other than the specific link are assumed to be congested links, and links not included in the first travel route are free links for links other than the specific link. The second route search means 4 for searching for a route from the departure point to the destination on the assumption that the second traveling route is specified based on the search result. The route match determination means 45 for determining whether or not the first travel route and the second travel route match. When it is determined that the first travel route and the second travel route do not match, the probe center 4 Additional traffic information acquisition means 46 for acquiring additional traffic information that is traffic congestion information of links including links other than specific links as center traffic information, and searching for a route from the departure point to the destination using the acquired additional traffic information This is an electronic control unit that constitutes the three-route search means 47 and the like and controls the entire navigation device 1. The CPU 51 as an arithmetic device and a control device, the RAM 51 that is used as a working memory when the CPU 51 performs various arithmetic processes, stores route data and the like when a route is searched, and a control program In addition, an internal storage device such as a ROM 53 in which a route search processing program (see FIG. 8), which will be described later, is recorded, and a flash memory 54 in which a program read from the ROM 53 is stored is provided.

  The operation unit 24 is operated, for example, when inputting a departure point as a travel start point or a destination point as a travel end point, and includes a plurality of operation switches (not shown) such as various keys and buttons. Then, the navigation ECU 23 performs control to execute various corresponding operations based on switch signals output by pressing the switches. The operation unit 24 can also be configured by a touch panel provided on the front surface of the liquid crystal display 25.

  Further, the liquid crystal display 25 includes a map image including a road, traffic information, operation guidance, operation menu, key guidance, a planned travel route from the departure point to the destination, guidance information along the planned travel route, news, weather, etc. Forecast, time, mail, TV program, etc. are displayed. Moreover, it is used also when displaying the information regarding the searched facility when a facility search is performed. In addition, based on the distributed VICS information and center traffic information, guidance is provided indicating a traffic jam section or a regulation section on the road. For example, when guiding a traffic jam section on a road, a color corresponding to the traffic jam degree along the road in the map image displayed on the liquid crystal display 25 (for example, traffic jam is red, congestion is orange, and sky is blue) Display the arrow.

  In addition, the speaker 26 outputs voice guidance for guiding traveling along the planned traveling route and traffic information guidance based on an instruction from the navigation ECU 23. It is also used when outputting information related to the found facility when the facility search is performed.

  The DVD drive 27 is a drive that can read data recorded on a recording medium such as a DVD or a CD. The map information DB 35 is updated based on the read data.

  The communication module 6 is a communication device for receiving center traffic information and VICS information transmitted from the probe center 4, the VICS center 5, etc., and corresponds to, for example, a mobile phone or DCM.

  Next, a route search processing program executed in the navigation device 1 configuring the route search system 2 having the above configuration will be described with reference to FIG. FIG. 8 is a flowchart of the route search processing program according to this embodiment. Here, the route search processing program is executed after the destination setting operation is received by the operation unit 24 in the navigation device 1, and the route to the destination using the traffic jam information distributed from the probe center 4 or the VICS center 5. It is a program that performs search processing. The program shown in the flowchart of FIG. 8 below is stored in the RAM 52, ROM 53, etc. provided in the navigation ECU 23 and executed by the CPU 51.

  First, in the route search processing program, in step (hereinafter abbreviated as S) 1, the CPU 51 sets a destination based on the operation received by the operation unit 24.

  Next, in S <b> 2, the CPU 51 acquires VICS information from the VICS center 5. In S2, the VICS information related only within a specific area such as a prefecture where the vehicle is located or a neighboring prefecture is received via FM multiplex broadcasting. In addition, during traveling on a highway where a radio beacon is installed, VICS information relating to the highway around the current position of the vehicle (for example, within 200 km) is further received via the radio beacon. Further, during traveling on a main general road where an optical beacon is installed, VICS information relating to the main general road around the current position of the vehicle (for example, within 30 km) is further received via the optical beacon. Note that the VICS information acquired in S2 includes traffic jam information (basic traffic jam information) that specifies the degree of traffic jam on the main road where the sensor is installed. Specifically, it is information that identifies the main road as “congested”, “congested”, or “empty” in descending order of the degree of congestion. Therefore, the traffic jam information that can be acquired by the CPU 51 in S2 is traffic jam information related to only a specific link (that is, a link in a specific area such as a prefecture where the vehicle is located or a neighboring prefecture and where a sensor is installed). .

  Subsequently, in S3, the CPU 51 executes a first route search process for searching for a route from the departure place to the destination set in S1 using the VICS information (including basic traffic jam information) acquired in S2. . The departure point may be the current position of the vehicle or a designated point (for example, home). In the first route search process of S3, a known Dijkstra method is used. Specifically, the route is searched from the departure side and the destination side, and the search cost (node) accumulated from the departure side in the overlapping portion of the search from the departure side and the search from the destination side. Cost and link cost) and a search cost accumulated from the destination side, that is, a cost addition value is calculated. Then, the route having the smallest cost addition value is identified as the first travel route that is the recommended route. The link cost is 1.5 times for links determined to be “congested” based on basic traffic jam information, 1.2 times for links determined to be “congested”, and determined to be “free”. In the link that is used, it is 0.8 times. As a result, it is possible to avoid a congested road and search for a route that preferentially travels on an empty road.

  After that, in S4, the CPU 51 uses the VICS information (including basic traffic jam information) acquired in S2, and among the links included in the first travel route, other than the specific link for which the basic traffic jam information was acquired in S2. Assuming that the link of No. 1 is congested and that links other than the specific link for which basic traffic jam information was acquired in S2 are available among the links not included in the first travel route. A second route search process for searching for a route from the ground to the destination set in S1 is executed. Specifically, among the links included in the first travel route, the degree of congestion of links other than the specific link is “congested”, and the link cost is 1.5 times. In addition, among the links not included in the first travel route, the congestion degree of links other than the specific link is set to “free”, and the link cost is set to 0.8 times. Others are the same as the first route search process (S3) described above. Then, the route with the minimum cost addition value is specified as the second travel route that is the recommended route.

  Subsequently, in S <b> 5, the CPU 51 determines whether or not it is necessary to acquire center traffic information from the probe center 4. Specifically, it is determined whether or not the first travel route specified in S3 matches the second travel route specified in S4.

  Here, the case where the first travel route and the second travel route do not coincide with each other means that the traffic congestion degree of the link in which the traffic congestion degree could not be determined by the basic traffic congestion information in the first travel route is “congestion”. When the congestion level of a link whose traffic congestion level could not be determined based on basic traffic congestion information other than one travel route is “empty” (that is, when it is assumed that the first travel route is the most congested traffic situation) Indicates the possibility of a route other than the first travel route being a recommended route. For example, as shown in FIG. 9, when the link H, the link I, the link K, and the link L are links for which the congestion degree cannot be determined based on the basic congestion information, the first travel from the departure point 61 to the destination 62 is performed. The case where the route “A → D → I → L” is specified as the route 65 and the route “A → D → H → K” is specified as the second travel route 66 will be described. In this case, as a result of newly acquiring the congestion levels of the link H, the link I, the link K, and the link L for which the congestion level could not be determined from the basic congestion information from the probe center 4, “A There is a possibility that the route “A → D → H → K”, which is the second travel route 66, or a route other than the route “D → I → L” may be recommended. Therefore, it is determined that the center traffic information needs to be acquired from the probe center 4.

  On the other hand, when the first travel route and the second travel route coincide with each other, the traffic congestion degree of the link in which the traffic congestion degree cannot be determined based on the basic traffic congestion information within the first travel route is temporarily “congestion”. This is a case where the congestion level of the link whose traffic congestion level could not be determined by the basic traffic congestion information other than the travel route is “empty” (that is, when it is assumed that the first travel route is the most congested traffic situation). However, this indicates that the first travel route is the recommended route. As described above, when the link cost is adjusted based on the traffic jam information distributed from the probe center 4, the link having the traffic jam degree “congested” is most increased, and the link having the traffic jam degree “empty” is the highest. Lower. Therefore, it is assumed that the congestion level of the link for which the congestion degree could not be determined by the basic congestion information in the first travel route is “congestion” that increases the link cost most, and the congestion degree is determined by the basic congestion information other than the first travel route. If the same route is the recommended route even if it is assumed that the degree of congestion of the link that could not be determined is “empty” that most reduces the link cost, the first traffic information is received even if center-specific traffic information is received from the probe center 4. The travel route is the recommended route. For example, as shown in FIG. 10, when the link H, the link I, the link K, and the link L are links for which the degree of traffic congestion cannot be determined based on the basic traffic jam information, A case where the same route “A → D → I → L” is specified as the route 67 and the third travel route 68 will be described. In that case, when the search degree is newly acquired from the probe center 4 when the congestion level of the link H, the link I, the link K, and the link L is newly determined from the basic congestion information, Compared with the route search process, the link cost of the link I and the link L is lowered but not increased. In addition, the link cost of the link H and the link K is increased but not decreased as compared with the second route search process. As a result, the route “A → D → I → L”, which is the first travel route 67, becomes the recommended route again. Therefore, it is determined that there is no need to acquire center traffic information from the probe center 4.

  In the determination process of S5, when it is determined that the center traffic information needs to be acquired from the probe center 4, that is, when it is determined that the first travel route and the second travel route do not match (S5: YES), the process proceeds to S6.

  On the other hand, when it is determined that it is not necessary to acquire the center traffic information from the probe center 4, that is, when it is determined that the first travel route and the second travel route match (S5: NO), in S3 The identified first travel route is identified as a guide route (S8), and travel guidance is performed based on the identified guide route (S9).

  In S6, the CPU 51 requests center traffic information from the probe center 4, and acquires the center traffic information distributed in response to the request. The center traffic information to be distributed is information relating to the vicinity of the departure point, the destination, and the guidance route currently set for the vehicle to be distributed. The center traffic information acquired in S6 includes traffic jam information (additional traffic jam information). In the present embodiment, the congestion information related to the links whose congestion levels are specified as “congested”, “congested”, and “empty” is included. Further, additional traffic jam information is newly acquired for the link whose traffic jam degree has already been determined based on the basic traffic jam information acquired in S2. In this case, information may be overwritten (additional traffic information is prioritized) or information may not be overwritten (basic traffic information is prioritized). In addition, about the link from which the congestion degree was determined by the basic congestion information acquired by said S2, it is good also as a structure which does not receive additional congestion information (or is not delivered from the probe center 4).

  Next, in S7, the CPU 51 uses the VICS information (including basic traffic information) acquired in S2 and the center traffic information (including additional traffic information) acquired in S6, and the purpose set in S1 from the departure point. A third route search process for searching for a route to the ground is executed. The link cost is 1.5 times higher for links that are newly identified as “congested” by the additional traffic information, and the link cost is 1.2 times higher for links that are specified as “congested”. The link cost is set to 0.8 times for the created link. Others are the same as the first route search process (S3) described above. Then, the route having the minimum cost addition value is specified as the third travel route that is the recommended route.

  Subsequently, in S8, the CPU 51 specifies the third travel route specified in S7 as a guide route.

  Thereafter, in S9, the CPU 51 performs traveling guidance based on the guidance route specified in S8.

As described in detail above, the navigation device 1 according to this embodiment, the route search method using the navigation device 1 and the computer program executed by the navigation device 1 acquire basic traffic jam information from the VICS center 5. (S2) A first route search process for searching for a route to the destination based on the acquired basic traffic jam information is performed (S3). A second route that searches for a route from the starting point to the destination, assuming links that are not included in the first travel route and links other than the specific link are assumed to be empty links. Search means is performed (S4), and if it is determined that the first travel route and the second travel route do not match, the probe center 4 Third traffic search processing for acquiring additional traffic information as center traffic information from the probe center 4 (S6) and searching for a route again based on the acquired additional traffic information. (S7), and the third travel route specified by the third route search process is used as the guide route (S8). Therefore, it is possible to appropriately determine when the center traffic information needs to be acquired from the probe center 4. It becomes. That is, when the second travel route searched on the assumption that the traffic situation should most avoid the first travel route does not coincide with the first travel route, as a result of acquiring the center traffic information, a different route is determined as the destination. (That is, the first travel route is different from the third travel route), and it can be appropriately determined that the center traffic information needs to be acquired from the probe center 4. . Therefore, communication with the probe center 4 that becomes unnecessary as a result can be reduced in advance, and communication processing, communication time, communication cost, and the like with the probe center 4 can be reduced.
Further, VICS information is acquired from the VICS center 5 as basic traffic information, and center traffic information collected and collected as probe information from the probe center 4 is acquired as additional traffic information, so traffic information supplied from the VICS is acquired. Communication information with the probe center 4, communication time, communication cost, etc., while making it possible to execute appropriate route search processing using traffic information collected and statistically collected as probe information. It becomes possible to decrease.

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, a probe center that provides traffic information based on probe information has been described as an example of a center that acquires center traffic information. However, the center may be configured to acquire from a center other than the probe center.

In the present embodiment, the traffic jam information acquired as additional traffic jam information is traffic jam information acquired from the probe center. However, statistical traffic information stored in the DB of the navigation device 1 (probe traffic information collected in the past, The traffic information may be acquired from traffic information obtained by statistically processing VICS information. And even if it is a case where it is a case where it is a structure which acquires the statistical traffic information stored in DB of navigation apparatus 1 as additional traffic congestion information, it is possible to apply the route search processing program shown in FIG. However, in S6, it is set as the structure which acquires (reads) statistical traffic information not from the probe center 4 but from DB of the navigation apparatus 1. FIG.
As a result, when the navigation device 1 searches for a route alone without communicating with the probe center 4, as a result of acquiring traffic jam information from the storage means, a different route becomes a recommended route to the destination (that is, the first travel) It is possible to appropriately determine a case where there is a possibility that the route and the third travel route are different. Accordingly, it becomes possible to reduce the traffic information stored in the DB, which is unnecessary as a result, and to reduce the processing load on the CPU and the search time for reading the traffic information stored in the DB. It becomes possible to plan.

  Further, in the present embodiment, when a route search is performed in the navigation device 1, the link cost of the “congestion” link is 1.5 times the link cost, and the link of the “congestion” congestion rate is set to 1. The search cost is calculated by multiplying the link cost by 0.8 times for links with a traffic congestion degree of “empty”, but the rate of increase and decrease of the link cost based on the level of traffic congestion is changed to another rate. Also good. Further, the link cost may not be changed for the “congested” link.

  In this embodiment, the degree of traffic congestion is classified into three levels of “traffic jam”, “congestion”, and “empty”, but may be divided into two levels or four or more levels.

  Further, in the present embodiment, the additional traffic jam information acquired from the probe center 4 is information that specifies only the links of “traffic jam”, “congested”, and “empty”, but the traffic jam level is “traffic jam”. It is good also as information which specifies only a "vacant" link.

  In the present embodiment, the additional traffic congestion information distributed from the probe center 4 includes the traffic congestion information collected and statistically collected as probe information, and the traffic congestion based on the VICS information transmitted from the VICS center 5 to the probe center 4. However, the additional traffic jam information may be information based only on traffic jam information collected and probed as probe information.

1 Navigation Device 2 Route Search System 3 Vehicle 4 Probe Center 5 VICS Center 51 CPU
52 RAM
53 ROM

Therefore, conventionally, it has been proposed to use the traffic information supplied from the VICS in combination with the traffic information acquired from the probe center or the like. For example, in JP-2003-1 3 9556 JP, first determines whether there is a congestion area on the guidance route based on the traffic jam information supplied from VICS, it is determined that there is a congestion area on the guidance route In some cases, it has been proposed to obtain more detailed traffic information from the probe center.

JP 2003-139556 A (page 3, FIG. 3)

Claims (6)

Basic traffic information acquisition means for acquiring basic traffic information that is traffic information of a specific link without going through the center that distributes the center traffic information;
Destination setting means for setting the destination;
Using the basic traffic information acquired by the basic traffic information acquisition means, a route from a departure place to a destination set by the destination setting means is searched, and a first travel route is specified based on the search result. First route search means;
Assuming that links other than the specific link are congested among links included in the first travel route, links other than the specific link are vacant among links not included in the first travel route. A second route search means for searching for a route from the departure place to the destination set by the destination setting means, and specifying a second travel route based on the search result;
Route match determination means for determining whether or not the first travel route and the second travel route match;
When it is determined that the first travel route and the second travel route do not coincide with each other, additional traffic congestion information that is traffic congestion information of a link including a link other than the specific link is acquired as the center traffic information from the center. Additional traffic information acquisition means,
Using the additional traffic information acquired by the additional traffic information acquisition means, and a third route search means for searching for a route from a departure place to the destination set by the destination setting means, Route search device. The basic traffic information acquisition means acquires traffic information supplied from a road traffic information communication system (VICS: registered trademark) as the basic traffic information,
The route search device according to claim 1, wherein the additional traffic information acquisition unit acquires traffic information collected and statistically collected as probe information as the additional traffic information. Basic traffic information acquisition means for acquiring basic traffic information that is traffic information of a specific link from outside,
Storage means for storing additional traffic information that is traffic information of links including links other than the specific link;
Destination setting means for setting the destination;
Using the basic traffic information acquired by the basic traffic information acquisition means, a route from a departure place to a destination set by the destination setting means is searched, and a first travel route is specified based on the search result. First route search means;
Assuming that links other than the specific link are congested among links included in the first travel route, links other than the specific link are vacant among links not included in the first travel route. A second route search means for searching for a route from the departure place to the destination set by the destination setting means, and specifying a second travel route based on the search result;
Route match determination means for determining whether or not the first travel route and the second travel route match;
When it is determined that the first travel route and the second travel route do not match, additional traffic information acquisition means for acquiring the additional traffic information from the storage means;
Using the additional traffic information acquired by the additional traffic information acquisition means, and a third route search means for searching for a route from a departure place to the destination set by the destination setting means, Route search device. The basic traffic information acquisition means acquires traffic information supplied from a road traffic information communication system (VICS: registered trademark) as the basic traffic information,
The route search device according to claim 3, wherein the additional traffic information acquisition unit acquires the traffic information stored in the storage unit as the additional traffic information. Basic traffic information acquisition step for acquiring basic traffic information that is traffic information of a specific link without going through the center that distributes the center traffic information;
A destination setting step for setting a destination;
The basic traffic information acquired in the basic traffic information acquisition step is used to search for a route from the departure place to the destination set in the destination setting step, and the first travel route is specified based on the search result. A first route search step;
Assuming that links other than the specific link are congested among links included in the first travel route, links other than the specific link are vacant among links not included in the first travel route. A second route search step for searching for a route from the departure point to the destination set by the destination setting step and specifying the second travel route based on the search result;
A route match determination step for determining whether or not the first travel route and the second travel route match;
When it is determined that the first travel route and the second travel route do not coincide with each other, additional traffic congestion information that is traffic congestion information of a link including a link other than the specific link is acquired as the center traffic information from the center. Additional traffic information acquisition step,
A third route search step for searching for a route from a departure place to a destination set by the destination setting step using the additional traffic jam information acquired by the additional traffic jam information acquisition step. Route search method. On the computer,
Basic traffic information acquisition function that acquires basic traffic information that is traffic information of a specific link without going through the center that distributes center traffic information;
Destination setting function to set the destination,
Using the basic traffic information acquired by the basic traffic information acquisition function, a route from a departure place to a destination set by the destination setting function is searched, and a first travel route is specified based on the search result. A first route search function;
Assuming that links other than the specific link are congested among links included in the first travel route, links other than the specific link are vacant among links not included in the first travel route. A second route search function that searches for a route from the departure point to the destination set by the destination setting function and identifies the second travel route based on the search result;
A route match determination function for determining whether or not the first travel route and the second travel route match;
When it is determined that the first travel route and the second travel route do not coincide with each other, additional traffic congestion information that is traffic congestion information of a link including a link other than the specific link is acquired as the center traffic information from the center. Additional traffic information acquisition function,
A third route search function for searching a route from a departure point to a destination set by the destination setting function using the additional traffic jam information acquired by the additional traffic jam information acquisition function;
A computer program for executing

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