JP2006071390A - Navigation system, route search server and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle navigation system capable of performing a route search, without a changeover of road network data, when the route search is performed considering traffic congestion by using road network data based on past statistics. <P>SOLUTION: A navigation system 10 consists of a route search server 20 and a navigation terminal 30. The road network data for route searches are composed of road network data by periods of time which are an accumulation of road link costs acquired at every predetermined period of time from past road link cost data. The search server 20 computes, as an estimated required time duration, a time duration to be required from the place of departure up to a destination by an approximate distance from the place of departure and the destination and a predetermined average traveling speed. A network data selection means 23 computes time which is the sum of departure time and a time duration being a predetermined rate of the estimated required time duration, and selects road network data corresponding to the computed time to use the data for a route search. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle navigation system, a route search server, and a program, and in particular, an in-vehicle navigation for searching for a route using road network data (link cost data) based on past statistics in consideration of traffic jams. The present invention relates to a navigation system, a route search server, and a program capable of performing route search without switching road network data.

  2. Description of the Related Art Conventionally, an in-vehicle navigation device that provides an automobile driver with an optimal route from a departure place to a destination has been provided. A conventional navigation device is a map data storage device such as a CD-ROM or IC card in which map data is recorded, a display device, a gyro, a GPS (Global Positioning System), a vehicle speed sensor, and other current positions and directions of vehicles. A vehicle movement detection device that detects the vehicle, reads map data including the current position of the vehicle from the map data storage device, draws a map image around the vehicle position on the display device based on the map data, and The position mark (location) is displayed superimposed on the display screen, the map image is scrolled as the vehicle moves, the map image is fixed on the screen and the vehicle position mark is moved, and the vehicle You can see at a glance whether you are driving.

  Usually, such a vehicle-mounted navigation device is equipped with a route guidance function that allows a driver to easily travel to a desired destination without making a mistake on the road. According to this route guidance function, the route with the lowest cost connecting from the starting point to the destination is searched using the map data by performing a simulation calculation such as Dijkstra method, and the searched route is stored as a guide route. While traveling, the guide route is drawn thickly on the map image with a different color from other roads and displayed on the screen, or the vehicle approaches within a certain distance to the intersection where the route on the guide route should be changed Sometimes, the driver can easily grasp the optimum route to the destination by drawing an arrow indicating the route at the intersection where the route should be changed on the map image and displaying it on the screen.

  The in-vehicle navigation device is a stand-alone navigation device having a route search function and map data, but such a navigation device needs to have all the functions necessary for navigation, and the device is large. The price was high. Due to recent developments in communication and information processing technologies, so-called communication-type navigation systems that add communication functions via a network to vehicle-mounted navigation devices and communicate with a route search server to acquire guide route data and map data have become widespread. Have been doing. Furthermore, a system using a mobile phone as a navigation terminal has been put into practical use as a navigation system for pedestrians.

  By the way, the link cost used for the route search in the in-vehicle navigation system generally adopts the required time calculated based on the standard speed passing through the link. In the route search using such link costs, the situation of traffic congestion encountered when actually driving with a car is not reflected in the route search. Therefore, the driver listens to road information and traffic jam information announced separately from the traffic information center by radio etc., and changes the travel route from the guide route guided by the navigation system to another route, or the estimated arrival time It was necessary to grasp the delay.

  However, communication navigation systems such as those described above are also becoming popular in in-vehicle navigation systems, and in the road traffic information communication system (VICS), for example, the required time cost of the VICS link is 5 minutes apart. Since it is measured, it is statistically processed by road, time zone, day of week, etc., and the actual link cost is accumulated as road network data, and network data based on these past performance data is stored in the route search server. An environment that can be accumulated and used for route search has been established.

  From such a background, an attempt has been made to perform navigation in consideration of traffic jams. For example, an in-vehicle navigation device disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 10-19593) is known. As shown in FIG. 5, the in-vehicle navigation device disclosed in Patent Document 1 includes a navigation device body 1 constituted by a microcomputer, a liquid crystal monitor (display device) 2, a CD-ROM 3 storing map data, GPS receiver 4 for detecting vehicle direction, vehicle speed, etc. by satellite navigation, beacon receiver 5, FM multiplex receiving unit 6, gyro 7 for detecting the rotation angle of the vehicle, vehicle speed pulse detector 8, and memory 9 for traffic information data It has.

  The navigation device main body 1 displays a map in the vicinity of the current position of the vehicle on the liquid crystal monitor 2, and displays a guidance route from the departure point to the destination, a vehicle position mark, and other guidance information. The CD-ROM 3 stores map data composed of road layers, background layers, character / symbol layers, and the like according to scales. The beacon receiver 5 and the FM multiplex receiving unit 6 are receivers for receiving traffic information. The beacon receiver receives traffic information for a relatively narrow area, and traffic information for a relatively wide area multiplexed in FM broadcasting. Receive. The received traffic information is stored in the traffic information data memory 9 and becomes past traffic information data. In this data, for example, an average value of link costs for the past four weeks is stored every 10 minutes.

  The navigation device body 1 then travels from the departure point specified by the user to the destination based on the map data stored in the CD-ROM 3 and the traffic information acquired via the beacon receiver 5 or the FM multiplex receiving unit 6. The route with the lowest cost is searched as a guide route, and a map image in the vicinity of the current position of the vehicle is displayed on the monitor 2 using the map data stored in the CD-ROM 3, and the vehicle position mark and the guidance route are displayed. It is displayed according to the map image, and various guidance information is provided to the user according to the movement of the vehicle.

  When searching for a route, the navigation device body 1 calculates the required time to the destination based on the latest traffic information received via the beacon receiver 5 or the FM multiplex receiving unit 6. If it exceeds 1 hour, the guidance route is searched using the data stored in the traffic information memory 9 for the guide route exceeding 1 hour. To do. That is, the navigation device calculates the required time of the guide route searched using the link cost database based on the latest traffic information, and switches to the past link cost database for route search exceeding 1 hour. It is configured to perform route guidance in consideration of traffic congestion by obtaining a guidance route using the link cost at the same time.

  Further, in the following Patent Document 2 (Japanese Patent Laid-Open No. 11-325937), in an in-vehicle navigator provided with a position detection means, a storage reproduction means storing a map and road data, and a traffic jam information acquisition means, An in-vehicle navigator is disclosed in which a route search in consideration of a change in a traffic jam situation can be performed to obtain a more accurate route search result. This in-vehicle navigator obtains a function for predicting a road cost with respect to a time axis based on the traffic jam information acquired by the traffic jam information acquisition means (which expresses the expected road cost as a function of time), and this function and the map The route search is performed based on the road data as follows. That is, for a plurality of unconfirmed points between the departure point and the target point, a point having the smallest route length based on the function from the departure point is selected and set as a confirmed point among the plurality of unconfirmed points. To the first route length from the first unconfirmed point connected to the confirmed point to the departure point when passing through the first confirmed point set in the confirmed process The route length update process is repeatedly executed until the target point is set as the fixed point.

Japanese Patent Laid-Open No. 10-19593 (FIG. 1) Japanese Patent Laid-Open No. 11-325937 (FIGS. 1 and 4)

  A difficult point of route search in consideration of traffic jams in the navigation system is that the state of traffic jams changes as the route search starts from the departure point. For example, even if road network data (link cost data) based on past statistics is used, the network data itself is network data at a specific time, and the navigation device is located when the route search proceeds to the destination. The road position may be the time of occurrence of traffic congestion. On the other hand, when you departed during a traffic jam, but the traffic jam has disappeared over time, if you search for a route using a network in a past traffic jam with the same departure time, the arrival prediction will be too late for the actual scheduled time. There was a problem of searching for guidance data.

  With respect to such problems, the in-vehicle navigation device disclosed in Patent Document 1 has been searched for a predetermined time (when the link cost of the guide route is 1 hour), Among them, the database is switched to the past link network data in the same time zone, and the subsequent route search is performed. However, in the in-vehicle navigation device disclosed in Patent Document 1, the database is switched when the link cost of the guide route has passed 1 hour, and the traffic congestion at that point may be rapidly advanced when 1 hour has passed. . In order to avoid this, it is only necessary to shorten the database switching interval. However, it is necessary to frequently replace network data for searching during the search, which increases the processing load on the route search server. There is a problem of becoming.

  In addition, the in-vehicle navigator disclosed in Patent Document 2 increases the processing load for the route search server to perform a function calculation. That is, for example, when the route search server performs a route search by the Dijkstra method, the link cost must be calculated by a function of time for each link spread by the Dijkstra method. There is a problem that the processing load of the search server becomes large.

  As a result of various studies to solve the above-mentioned problems, the inventor of the present application selects one network data in a specific time zone from a database in which network data taking into account the traffic jam situation for each past time zone is accumulated. If the intermediate time is selected as the specific time zone based on the estimated required time from the departure point to the destination, the route search is less susceptible to changes due to the time of traffic congestion. The present invention has been completed by paying attention to the fact that the processing does not become slower than the conventional route search time and does not increase the processing load of the route search server.

  That is, the present invention aims to solve the above-described problems, and in a vehicle-mounted navigation system that searches for a route using road network data (link cost data) based on past statistics in consideration of traffic congestion, It is an object of the present invention to provide a navigation system, a route search server, and a program that can perform a route search without switching network data.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
A navigation system in which a route search server and a navigation terminal communicate via a network,
The navigation terminal includes route search request processing means for transmitting a route search request including at least a departure place, a destination, a departure time or an estimated arrival time to a route search server,
The route search server includes a network data DB that accumulates road network data according to time obtained by accumulating road link costs for each predetermined time from past road link cost data, route search means, and from a departure place to a destination. An estimated time calculating means for calculating the estimated required time, and network data selecting means for selecting one of the road network data from the estimated required time and the departure time,
The estimated time calculating means calculates the required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed as the estimated required time,
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And selecting the road network data corresponding to the calculated time,
The route search means searches for a route using road network data selected by the network data selection means.

The invention according to claim 2 of the present application is the invention according to claim 1, wherein the route search server further includes network data statistical type search means,
The road network data includes a road network group in which past road link costs are accumulated according to a plurality of predetermined statistical types, and the road network data according to one statistical type is a time at which road link costs are accumulated at predetermined times. Consists of separate road network data,
The network data statistical type searching means determines road network data of a corresponding statistical type from the corresponding road network data group based on the date and day of the week when the route search is requested.

  The invention according to claim 3 of the present application is characterized in that, in the invention according to claim 2, the statistical type is a combination of date, day of the week, and weather.

  The invention according to claim 4 of the present application is characterized in that, in the invention according to claim 3, the statistic type is a specific singular day or a singular day group as an independent statistic type.

  The invention according to claim 5 of the present application is the invention according to claim 1 or 2, characterized in that the approximate distance is a distance obtained by multiplying a linear distance between the departure place and the destination by a predetermined multiple. .

The invention according to claim 6 of the present application is
A route search server that communicates via a network with a navigation terminal having route search request processing means for transmitting a route search request including a departure point, destination, departure time or estimated arrival time to the route search server,
The route search server includes a network data DB that accumulates road network data according to time obtained by accumulating road link costs for each predetermined time from past road link cost data, route search means, and from a departure place to a destination. An estimated time calculating means for calculating the estimated required time, and network data selecting means for selecting one of the road network data from the estimated required time and the departure time,
The estimated time calculating means calculates the required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed as the estimated required time,
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And selecting the road network data corresponding to the calculated time,
The route search means searches for a route using road network data selected by the network data selection means.

The invention according to claim 7 of the present application is the invention according to claim 6, wherein the route search server further comprises network data statistical type search means,
The road network data includes a road network group in which past road link costs are accumulated according to a plurality of predetermined statistical types, and the road network data according to one statistical type is a time at which road link costs are accumulated at predetermined times. Consists of separate road network data,
The network data statistical type searching means determines road network data of a corresponding statistical type from the corresponding road network data group based on the date and day of the week when the route search is requested.

  The invention according to claim 8 of the present application is characterized in that, in the invention according to claim 6, the statistical type is a combination of date and day of the week and weather.

  The invention according to claim 9 of the present application is characterized in that, in the invention according to claim 8, the statistic type is further a specific singular day or a singular day group as an independent statistic type.

  The invention according to claim 10 of the present application is the invention according to claim 6 or 7, characterized in that the approximate distance is a distance obtained by multiplying a linear distance between the departure place and the destination by a predetermined multiple. .

According to the eleventh aspect of the present invention, there is provided a navigation terminal including a route search request processing means for transmitting a route search request including a departure point, a destination, a departure time or an estimated arrival time to a route search server, and a network. A route search server that communicates with each other, a network data DB that accumulates road network data for each time obtained by accumulating road link costs for each predetermined time from past road link cost data, a route search means, a departure place, A route search server comprising: estimated time calculating means for calculating an estimated required time from a destination to a destination; and network data selecting means for selecting one of the road network data from the estimated required time and departure time To the computer
The estimated time calculation means is a process as an estimated time calculation means for calculating a required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed, as an estimated required time;
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And processing as network data selection means for selecting the road network data corresponding to the calculated time;
The route search means executes a process as route search means for searching for a route using the road network data selected by the network data selection means.

The invention according to claim 12 of the present application provides a navigation terminal including a route search request processing means for transmitting a route search request including a departure point, a destination, a departure time or an estimated arrival time to a route search server, and a network. A road search server that communicates the past road link costs according to a plurality of predetermined statistical types, and the road network data for one statistical type includes a road link cost for each predetermined time A network data DB storing road network data including time-specific road network data, route search means, estimated time calculating means for calculating an estimated required time from a departure place to a destination, and the estimated required time Network data for selecting one of the road network data from the departure time And-option unit, the computer constituting the network data statistics type searching means, route search servers with,
Processing as network data statistical type search means for determining road network data of a corresponding statistical type from the corresponding road network data group based on the date and day of the week at the time of the route search request;
The estimated time calculating means is a process as an estimated time calculating means for calculating an estimated distance from the starting point to the destination as an estimated required time from an approximate distance from the starting point to a destination, and a predetermined average moving speed;
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And processing as network data selection means for selecting the road network data corresponding to the calculated time;
The route search means is a program for executing processing as route search means for searching for a route using the road network data selected by the network data selection means.

  In the invention according to claim 13 of the present application, in the invention according to claim 11 or 12, the program further causes the computer to calculate a distance obtained by multiplying a linear distance between the departure place and the destination by a predetermined multiple from the departure place. A process as the estimated time calculating means for calculating the approximate distance to the destination is executed.

In the invention according to claim 1 of the present application, the route search server includes a network data DB that accumulates road network data according to time in which road link costs are accumulated at predetermined times from past road link cost data, and a route. Search means; estimated time calculating means for calculating an estimated required time from the departure place to the destination; and network data selecting means for selecting one of the road network data from the estimated required time and the departure time. Yes. Then, the required time from the departure point to the destination was calculated as the estimated required time from the approximate distance from the departure point to the destination and the predetermined average moving speed, and a predetermined percentage of the estimated required time was added to the departure time. A time is calculated, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time is calculated, and road network data corresponding to the calculated time is selected. The route search means searches for a route using the road network data selected by the network data selection means.
There is no need to switch network data, and the load on the route search server is not increased. In addition, the time to be selected changes depending on the length of the estimated required time, network data corresponding to that time can be used for route search, and route search is performed with network data close to the actual travel time zone, which is optimal It is possible to provide a navigation system with a high probability of searching for a simple guide route.

In the invention according to claim 2 of the present application, in the invention according to claim 1, the route search server further includes a network data statistical type search means, and the road network data includes a plurality of past road link costs. It consists of a road network group accumulated according to a predetermined statistical type, and road network data according to one statistical type consists of time-specific road network data in which road link costs for each predetermined time are accumulated. Then, the network data statistical type search means determines the road network data of the corresponding statistical type from the corresponding road network data group based on the date and day of the week when the route search is requested.
Therefore, it is possible to provide a navigation system capable of performing a route search in consideration of a traffic jam situation by using the road network data closest to the route search time as the road network data for the route search from the past road network data. It becomes like this.

  In the invention according to claims 3 to 4, the statistical type is based on a combination of date, day of the week, and weather, and a specific specific day or a specific day group is an independent statistical type. Therefore, it is possible to provide a navigation system that enables a route search reflecting past traffic conditions.

  In the invention according to claim 5 of the present application, since the approximate distance between the starting point and the destination is a distance obtained by multiplying the linear distance between the starting point and the destination by a predetermined multiple, the estimated required time can be easily calculated. Will be able to.

  In the inventions according to claims 6 to 10 of the present application, a route search server constituting the navigation system according to claims 1 to 5 can be provided.

  Moreover, in the invention concerning Claim 11 thru | or 12 of this application, the program for implement | achieving the route search server concerning Claim 5 thru | or 6 can be provided now. In the invention according to claim 13 of the present application, a program for realizing the route search server according to claim 10 can be provided.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. FIG. 1 is a block diagram showing a configuration of a navigation system according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the concept of road network data used in the present invention. FIG. 3 is a flowchart showing the operation procedure of the navigation system in the embodiment of the present invention, and FIG. 4 is a flowchart showing a subroutine for determining the statistical type of road network data in the flowchart of FIG.

  An in-vehicle navigation system 10 according to an embodiment of the present invention includes a route search server 20 and a navigation terminal 30 that communicate via a network as shown in FIG. The navigation terminal 30 sends a route search request including the departure point and the destination to the route search server 20, and the route search server 20 refers to the road network data based on the route search request received from the navigation terminal 30 and is optimal. The route is searched, and the optimum route obtained as a result of the search is distributed to the navigation terminal 30 as guide route data.

  Road network data (hereinafter simply referred to as network data) is defined as the road end points, branch points, inflection points, etc. as nodes (line) links that connect the nodes, and the distance required for each link and the travel distance It is data that accumulates time as link cost. Since roads generally have ups and downs, each link is a directional link with a direction, and a directional link along the direction of travel of the automobile (navigation terminal 30) is used for route search. Searches can be performed with distinction between uplink and downlink. In the route search, the optimum route is obtained by finding the route that minimizes the cumulative link cost from the starting point to the node and the link in order to reach the destination. As this search method, for example, a method called a well-known Dijkstra method is generally used.

  The navigation terminal 30 includes a GPS processing unit 31, a communication unit 32, an operation / display unit 33, a route search request processing unit 34, and a storage unit 35. The GPS processing means 31 receives and processes GPS satellite signals and measures the current position (latitude / longitude) of the navigation terminal 30. In the case of an in-vehicle navigation terminal, although not shown, signals such as acceleration sensors and rudder angle sensors mounted on the vehicle are used to complement positioning in places where GPS satellite signals cannot be received, such as in mountainous areas and tunnels. There may be provided means for receiving and detecting the moving speed and moving direction to calculate the position.

  The communication means 32 includes a wireless communication unit and communicates with the route search server 20. The operation / display means 33 includes keys, dials, a liquid crystal display device, etc., inputs for operating the navigation terminal 30, inputs such as departure and destination, guidance routes distributed from the route search server 20, and display of maps. Is used. The route search request processing means 34 uses the starting point and destination input using the operation / display means 33 or the current position of the navigation terminal 30 measured by the GPS processing means 31 as the starting point. Based on this, a route search request to be transmitted to the route search server 20 is created.

  The storage means 35 stores guide route data, map data, and the like, which are route search results distributed from the route search server 20, and these data are read out from the storage means 35 as necessary, and the operation / It is displayed on the display means 33. In general, a guide route and a mark indicating the current position of the navigation terminal 30 are superimposed on a map of a certain scale and a certain range including the current position of the navigation terminal 30 measured by the GPS processing means 31, and the current position of the navigation terminal 30 is overlaid. The position mark is displayed at the center of the display screen. Since the measured position information includes an error, route matching processing is performed to correct the current position on the guide route when the current position is deviated from the guide route. In addition, when voice guide data (for example, a voice message such as “This is a 300m intersection, please turn left”) is added to the guidance route data distributed from the route search server 20, it is sent via a speaker. Play and output voice messages to guide the driver.

  On the other hand, the route search server 20 includes a main control unit 21, an estimated time calculation unit 22, a network data selection unit 23, a route search unit 24, a guide route data creation unit 25, a communication unit 26, a network data statistical type search unit 27, a network. A data DB (database) 28 is provided. The main control unit 21 is mainly composed of a microprocessor, and includes storage means such as a RAM and a ROM like a general computer device, and controls each part by a program stored in these storage means. The communication means 26 is a communication means for receiving a route search request from the navigation terminal 3 and delivering guide route data as a result of the route search to the navigation terminal 30.

  The network data DB 28 stores map data and network data for route search. In this embodiment, network data based on past statistics collected from the road traffic information communication system (VICS) is stored. A plurality of routes are stored, and the route search means 24 searches for an optimum route to the destination by a search method such as the Dijklas method described above with reference to one network data from the plurality of network data. Details of the network data in this embodiment and a method for determining one network data used for route search will be described in detail later.

  The guide route data creation unit 25 creates data of the optimum guide route searched by the route search unit 24. The node and link number to be followed by the navigation terminal, and the direction and length of the link are represented by vector data. Expressed guide route data is created. By adding data such as a point (point) at which voice guidance is to be provided to the navigation terminal 30 and a voice message pattern to be reproduced at the point to the guidance data, a predetermined voice guidance is provided before the intersection. Can be provided.

  Here, the network data in the present embodiment will be described. Usually, when the link cost of a road network is expressed by the link length (distance), the network data is single. Similarly, even if the link cost is expressed in the required time, the link time is determined by dividing the link distance by the average speed of the vehicle (the legal speed or the average value during actual driving), and the link cost is used as the network. The data is single. A normal navigation system performs a route search based on this network data. However, in the present embodiment, in order to perform a route search taking into account the traffic jam situation, network data created by statistical processing from past actual traffic information is accumulated and used for the route search.

  That is, in this embodiment, a plurality of network data created by statistical processing described later from the road traffic data measured by the road traffic information communication system (VICS) is accumulated. That is, in the above VICS, the required time cost of the VICS link is measured at intervals of 5 minutes, for example. By using this, the day of the week (weekdays / holidays), national holidays, weather, month end, fifty days (every day) ), Statistical processing under conditions such as the end of consecutive holidays, the year-end and New Year holidays, special days such as Bon Festival, etc., defining the statistical type for each condition and time, and the road network data (hereinafter referred to as the statistical type of statistics Is created and stored in the network data DB 28. In this embodiment, this statistical processing condition is referred to as a statistical type.

  FIG. 2 is a schematic diagram showing the concept of this network data. FIG. 2 representatively shows the concept of two network data of network (NW) data statistical type A and statistical type B. The network data of statistical type A is, for example, network data for each hour when the weather is fine on Mondays that are not special days, and the network data of statistical type B is, for example, weather on consecutive holidays (holidays and holidays) that are special days Network data for each hour when is clear. As described above, the network data includes the node N at the end point, the intersection, and the inflection point of the road, and the link L that connects each node N (the node N and the link L are each given a unique identification number), The time required for each link is accumulated as the link cost of each link L. Here, the required time of each link L at the time is accumulated from the past actual traffic information at every time, for example, every 5 minutes. Accordingly, the network data of the statistical type A is not a single network as in DT1 to DTN in FIG. 2, but a plurality of pieces of network data by time are accumulated, and similarly, the network data of the statistical type B is also classified by time. A plurality of network data is accumulated. In FIG. 2, network data according to time from 16:55 to 17:50 every 5 minutes is schematically shown.

  As described above, the network data in the present embodiment is a network data group for each of a plurality of statistical types accumulated in the network data DB 28. The route search server 20 first determines the statistics of the network data used for route search. The type is determined, and then, it is determined which time of the network data of the determined statistical type is used. The network data statistical type search means 27, the estimated time calculation means 22 and the network data selection means 23 operate to make these determinations.

  First, when there is a route search request from the navigation terminal 30, the route search server 20 searches the network data statistical type search means 27 from the departure point from the calendar function, the specific day table (not shown), and the weather information data of the day. The network data type used for the route search is determined based on the weather conditions up to the destination. Next, the estimated time calculation means 22 calculates an estimated required time from the departure place to the destination. In this calculation, for example, a straight line distance from the starting point to the destination is obtained, and an approximate route is estimated to be 1.2 to 1.3 times the straight line distance. This is because there are curves and the like on the road.

Estimate this approximate road speed, for example, 20km / h for urban areas, 40km / h for suburbs, and if the straight distance is long, a highway is used on the way, so the average speed is estimated to be 60km / h. The required time (referred to as estimated time) is obtained. For example, if the starting point and the destination are 30km away from each other with a linear distance,
The estimated time is calculated such that the linear distance is 30 km × 1.3 ÷ 40 km / h≈1 hour.

  Next, the network data selecting unit 23 adds a time obtained by halving the estimated time (approximate required time) obtained by the estimated time calculating unit 22 to the departure time, and uses the network data corresponding to the time for the route search. To choose. For example, if the estimated time is 1 hour as described above, if the departure time is 17:00, 30 minutes, which is half the estimated time 1 hour, is added to the departure time, and 30 minutes have elapsed since the departure time. The route search is performed using the network data of 17:30, that is, the network data of 17:30. As a result, a route search is performed using network data close to the actual travel time zone, and the probability that an optimum guide route can be searched increases. The departure time is input at the navigation terminal 30 and the departure time is included in the route search request. When the departure time is not input at the navigation terminal 30, the current time is set as the departure time. Has been.

  This is compared with the in-vehicle navigation device disclosed in Patent Document 1 as follows. In the navigation device disclosed in Patent Document 1, if the departure time is 17:00, first, a route search is performed using the network data of 17:00, and when the route search advances by time, The route search data is switched (replaced) to the network data of the time, and the route search of the subsequent route is performed. Therefore, a network data switching process is required during the route search. In addition, since the network data is switched when the route search has elapsed for one hour regardless of the time required from the departure point to the destination, even if the route takes five hours to reach the destination, Network data will be used for route search, and despite the fact that network data reflecting past traffic conditions is used, the route search is likely to be affected by changes in traffic conditions and the probability of searching for the optimal route is reduced. End up.

  According to the present embodiment, the condition for statistically processing past road network data (link cost) is set as a statistical type, road network data by time is accumulated for each statistical type, and the statistical type is selected. By using the road network data that is closest to the day of the route search as road network data for the route search, it is possible to provide a navigation system that can perform a route search in consideration of the actual traffic jam situation.

  In addition, since the route search is performed by selecting one network data after ½ of the estimated required time from the departure point to the destination from the road network data by time, it is not necessary to switch the network data. The load on the route search server is not increased. In addition, the time to be selected changes depending on the length of the estimated required time, network data corresponding to that time can be used for route search, and route search is performed with network data close to the actual travel time zone, which is optimal The probability that a simple guide route can be searched increases.

  Next, a processing procedure in the navigation system 10 according to the present embodiment will be described. FIG. 3 is a flowchart showing a processing procedure in the navigation system 10 shown in FIG. 1, and FIG. 4 is a flowchart showing a subroutine for determining a statistical type of network data in the flowchart of FIG. First, in step S10, the navigation terminal 30 creates a route search request including the departure point and the destination, transmits the route search request to the route search server 20, and the route search server 20 receives the route search request.

  Next, in step S11, the route search server 20 determines the statistic type of the network data used by the network data statistic type search means 27 for the route search from the date of the day, weather conditions, and the like. That is, in the subroutine of FIG. 4, the network data statistical type search means 27 specifies the date of the current day in step S20 using the calendar function. Next, in step S21, the day of the week is specified, and holidays and holidays are identified. Next, in step S22, it is specified whether or not it falls on a special day such as the fifty days, the end of consecutive holidays, the year-end and New Year holidays, the Bon Festival, and the like. This peculiar day can be easily specified by creating a list of peculiar days used in statistical processing of network data.

  In step S23, the weather on that day (the weather around the destination from the departure point) is specified. The weather can be easily identified by acquiring the weather information from the server that provides the weather information of each place by the route search server 20. Next, the network data statistic type search unit 27 determines a corresponding statistic type (statistic type A, statistic type B, or other statistic type in FIG. 2) based on the information specified in steps S20 to S23 in step S24. For example, if the day is a weekday on June 10 and the weather is clear, the network data of the corresponding statistical type X is determined, the process is terminated, and the process returns to step S12 in FIG.

  In the process of step S12 in FIG. 3, the estimated time calculation unit 22 calculates the estimated required time from the departure place to the destination as described above. In this calculation, for example, as described above, a straight line distance from the starting point to the destination is obtained, and an approximate route is estimated to be 1.2 to 1.3 times the straight line distance. This approximate route is average travel speed, for example, 20 km / h for urban areas, 40 km / h for suburbs, and if the straight distance is long, a highway is used on the way, so the average travel speed is estimated to be 60 km / h. The time required for estimation (referred to as estimation time) is obtained.

  Next, in step S13, the network data selection means 23 adds a time halved from the estimated time (approximate required time) calculated in the previous step S12 to the departure time, and sets it as the elapsed time from the departure time. The network data corresponding to is selected to be used for route search. As in the example described above, if the estimated required time is 1 hour, if the departure time is set to 17:00, the network data after the elapse of 30 minutes that is 1/2 of the estimated time of 1 hour, that is, 17:30 Select network data.

  In step S14, the route search means 24 searches for the optimum route by using the selected network data (in the above example, network data of 17:30) as route search network data. Then, the guide route data creating means 25 creates guide route data in step S15 using the searched optimum route as a guide route. At this time, the arrival time to each node of the guide route is created as the elapsed time from the departure time. In step S16, the guide route data is distributed to the navigation terminal 30 via the communication means 26.

  The navigation terminal 30 that has received the distribution of the guidance route data from the route search server 20 stores the guidance route data in the storage means 35 as described above, reads the guidance route data from the storage means 35 as necessary, and operates the navigation terminal data. / Display on the display means 33.

  As described above in detail, according to the navigation system 10 according to the present invention, the network search is performed by selecting one piece of network data after ½ of the estimated time from the departure point to the destination, There is no need to switch data, and the load on the route search server is not increased. In addition, the time to be selected changes depending on the length of the estimated required time, network data corresponding to that time can be used for route search, and route search is performed with network data close to the actual travel time zone, which is optimal The probability that a simple guide route can be searched increases.

  In the description of the above embodiment, the example in which specific network data is selected from the time-specific network data based on the departure time and the estimated required time from the departure place to the destination has been described. A route search request may be made to the route search server based on the scheduled time (desired arrival time). In this case, a time obtained by subtracting half of the estimated required time (predetermined time) from the estimated arrival time may be calculated, and route search may be performed by selecting network data by time corresponding to this time. .

  The present invention is particularly suitable for a system for performing a route search by connecting the route search server 20 and many communication-type navigation terminals 30, and a road network with a large amount of data is stored on the route search server 20 side. Can provide a navigation system 10 having the advantage of always being able to receive a navigation service in consideration of a traffic jam situation based on the latest statistical data without storing network data. Further, by combining with the technology such as Japanese Patent Application No. 2002-371483 previously filed by the present applicant, the same route can be obtained in the middle of the route even when the route search is requested again.

It is a block diagram which shows the structure of the navigation system concerning the Example of this invention. It is a schematic diagram which shows the concept of the road network data used in this invention. It is a flowchart showing the operation procedure of the navigation system in the embodiment of the present invention, It is a flowchart which shows the subroutine for determining the statistic classification of the road network data in the flowchart of FIG. It is a block diagram which shows the structure of the conventional vehicle-mounted navigation apparatus.

Explanation of symbols

10. Navigation system 20 ... Route search server 21 ... Main controller 22 ... Estimated time calculation means 23 ... Network data selection means 24 ... Route search means 25 ··· Guide route data creation means 26 ··· Communication means 27 ··· Network data statistical type search means 28 ··· Network data DB
30 ... Navigation terminal 31 ... GPS processing means 32 ... Communication means 33 ... Operation / display means 34 ... Route search request processing means 35 ... Storage means

Claims (13)

A navigation system in which a route search server and a navigation terminal communicate via a network,
The navigation terminal includes route search request processing means for transmitting a route search request including at least a departure place, a destination, a departure time or an estimated arrival time to a route search server,
The route search server includes a network data DB that accumulates road network data according to time obtained by accumulating road link costs for each predetermined time from past road link cost data, route search means, and from a departure place to a destination. An estimated time calculating means for calculating the estimated required time, and network data selecting means for selecting one of the road network data from the estimated required time and the departure time,
The estimated time calculating means calculates the required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed as the estimated required time,
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And selecting the road network data corresponding to the calculated time,
The navigation system according to claim 1, wherein the route search means searches for a route using road network data selected by the network data selection means. The route search server further includes network data statistical type search means,
The road network data includes a road network group in which past road link costs are accumulated according to a plurality of predetermined statistical types, and the road network data according to one statistical type is a time at which road link costs are accumulated at predetermined times. Consists of separate road network data,
The network data statistical type search means determines road network data of a corresponding statistical type from the corresponding road network data group based on a date and a day of the week when a route search is requested. Navigation system.   The navigation system according to claim 2, wherein the statistical type is based on a combination of date, day of the week, and weather.   4. The navigation system according to claim 3, wherein the statistical type further includes a specific specific day or a specific day group as an independent statistical type.   The navigation system according to claim 1 or 2, wherein the approximate distance is a distance obtained by multiplying a linear distance between the departure place and the destination by a predetermined multiple. A route search server that communicates via a network with a navigation terminal having route search request processing means for transmitting a route search request including a departure point, destination, departure time or estimated arrival time to the route search server,
The route search server includes a network data DB that accumulates road network data according to time obtained by accumulating road link costs for each predetermined time from past road link cost data, route search means, and from a departure place to a destination. An estimated time calculating means for calculating the estimated required time, and network data selecting means for selecting one of the road network data from the estimated required time and the departure time,
The estimated time calculating means calculates the required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed as the estimated required time,
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And selecting the road network data corresponding to the calculated time,
The route search server, wherein the route search means searches for a route using road network data selected by the network data selection means. The route search server further includes network data statistical type search means,
The road network data includes a road network group in which past road link costs are accumulated according to a plurality of predetermined statistical types, and the road network data according to one statistical type is a time at which road link costs are accumulated at predetermined times. Consists of separate road network data,
The network data statistical type search means determines road network data of a corresponding statistical type from the corresponding road network data group based on a date and a day of the week when a route search is requested. Route search server.   The route search server according to claim 6, wherein the statistical type is based on a combination of date, day of the week, and weather.   9. The route search server according to claim 8, wherein the statistical type is a statistical type independent of a specific specific day or a specific date group.   The route search server according to claim 6 or 7, wherein the approximate distance is a distance obtained by multiplying a linear distance between the departure place and the destination by a predetermined multiple. A route search server that communicates via a network with a navigation terminal having route search request processing means for transmitting a route search request including a departure point, destination, departure time or estimated arrival time to the route search server, A network data DB that accumulates road link cost data for each predetermined time from road link cost data, a route search means, and an estimation that calculates an estimated required time from the departure point to the destination A computer comprising a route search server, comprising: time calculation means; and network data selection means for selecting one of the road network data from the estimated required time and departure time.
The estimated time calculation means is a process as an estimated time calculation means for calculating a required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed, as an estimated required time;
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And processing as network data selection means for selecting the road network data corresponding to the calculated time;
The route search means executes a process as a route search means for searching for a route using the road network data selected by the network data selection means. A route search server that communicates via a network with a navigation terminal having route search request processing means for transmitting a route search request including a departure point, destination, departure time or estimated arrival time to the route search server, A road network consisting of a road network group in which road link costs are accumulated according to a plurality of predetermined statistical types, and road network data according to one statistical type is a road network consisting of road network data by time in which road link costs are accumulated at predetermined times. One of the road network data is obtained from the network data DB storing data, route search means, estimated time calculating means for calculating an estimated required time from the departure place to the destination, and the estimated required time and departure time. Network data selection means to select and network data statistics type The computer constituting the route search server having a search means, and
Processing as network data statistical type search means for determining road network data of a corresponding statistical type from the corresponding road network data group based on the date and day of the week at the time of the route search request;
The estimated time calculation means is a process as an estimated time calculation means for calculating a required time from the departure point to the destination from the approximate distance from the departure point to the destination and a predetermined average moving speed, as an estimated required time;
The network data selection means calculates a time obtained by adding a predetermined percentage of the estimated required time to the departure time, or a time obtained by subtracting a predetermined percentage of the estimated required time from the estimated arrival time And processing as network data selection means for selecting the road network data corresponding to the calculated time;
The route search means executes a process as a route search means for searching for a route using the road network data selected by the network data selection means.   13. The program according to claim 11 or 12, wherein the program further causes the computer to use the estimated distance from the starting point to the destination as a distance obtained by multiplying a linear distance between the starting point and the destination by a predetermined multiple. It is characterized by executing processing as a calculation means.

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