JP2013050413A - Navigation system, navigation program, and navigation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly perform route guidance based on the latest map data in a client device while suppressing a communication amount between a server device and the client device.SOLUTION: A server device searches for a guiding route by using a server side map database, extracts difference information indicating the difference of the guidance routes between the server side map database and a client side map database on the basis of information specifying a version of the client side map database received from a client device, generates lacking information of generating guidance information in the client device as lacking guidance information, and transmits search result information including information specifying a route by which the guiding route can be specified as well as the lacking guidance information to the client device. The client device generates guidance information by using the information contained in the client side map database and the lacking guidance information.

Description

  The present invention relates to a navigation system comprising a client device having a client-side map database including at least road network information, and a server device having a server-side map database of the same version or newer than the client-side map database.

  A general on-vehicle navigation system is a stand-alone type system that performs route search using a map database mounted on a vehicle. On the other hand, there is also a cooperative navigation system in which a server device that performs a distribution service of various information related to navigation and an in-vehicle terminal (client device) that performs route search based on a map database are connected to be able to communicate with each other. . In such a cooperative navigation system, for example, the in-vehicle terminal can download the latest map data from the server device side or the difference data between the latest map data and the map data of the in-vehicle terminal to update the map database. . However, map data usually has a large data capacity, and even if it is difference data, the capacity becomes relatively large when the differences of the entire map are accumulated. For this reason, since there is a tendency that the amount of communication increases and the communication fee also increases, it is desired to suppress the volume of data transmitted from the server device to the in-vehicle terminal.

  Japanese Unexamined Patent Application Publication No. 2004-77254 (Patent Document 1) discloses a navigation system in view of such a problem. This navigation system compares the first route searched based on the current map data used in the in-vehicle terminal in the server device and the second route searched based on the latest map data on the server. . And when this navigation system detects the difference part of the 1st route and the 2nd route, it extracts only the map data of the block unit applicable to the difference part from the latest map data, The map difference data is distributed from the server device to the in-vehicle terminal.

JP 2004-77254 A

  The navigation system disclosed in Patent Document 1 can suppress the volume of data transmitted from the server device to the in-vehicle terminal as compared with the conventional one. However, since the map data volume is large even in block units, it is desirable to further reduce the data volume.

  In view of the above background, in a server-client type navigation system capable of searching for a route using the latest map data possessed by the server device, the client device has the latest communication volume while suppressing the amount of communication between the server device and the client device. It is desired to perform route guidance based on map data.

The characteristic configuration of the navigation system according to the present invention in view of the above problems is as follows.
A navigation system comprising: a client device having a client-side map database including at least road network information; and a server device having a server-side map database of the same version or newer than the client-side map database,
The server device is
A search information receiving unit for receiving search information including at least a guidance start point and a destination point, and version specifying information which is information capable of specifying the version of the client side map database;
A route search unit that searches for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
Based on the version identification information, a difference information extraction unit that extracts difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database;
Based on the difference information, a guide shortage information generating unit that generates information that is insufficient for generating guide information in the client device as guide shortage information;
A search result information transmitting unit that transmits search result information including route specifying information that is information that can specify the guide route and insufficient information for guidance to the client device,
The client device is
A search information transmitting unit for transmitting the search information and the version specifying information to the server device;
A search result information receiving unit for receiving the search result information from the server device;
And a guide information generating unit that generates the guide information using the information included in the client-side map database and the insufficient information for guidance based on the client-side map database and the search result information.

  According to this characteristic configuration, the guide route from the guide start point to the destination point is searched using the server side map database of the same version or newer than the client side map database. Accordingly, the guide route is always searched using the map database including the latest information in the navigation system. In the client device, in order to guide the user, it is sufficient if the information along the guide route is the latest information. According to this characteristic configuration, version specifying information that can specify the version of the client-side map database is provided to the server device. And the difference information extraction part of a server apparatus extracts the difference information which shows the difference of a server side map database and a client side map database along the searched guidance route. That is, since the difference information of both map databases is extracted in a very limited range, the calculation load and the data amount of the difference information are suppressed.

  By the way, it is a client-side map database that is used when the guidance information for actually guiding the user is generated. Therefore, when difference information exists in a range along the guidance route, the client device may not be able to appropriately generate guidance information. According to this feature configuration, information that is insufficient when the client device generates guidance information is generated as guidance shortage information based on the difference information. Then, the shortage information for guidance and the route specifying information that is information that can specify the guide route are transmitted as search result information from the server device to the client device. By using the information included in the client-side map database and the search result information including the insufficient information for guidance, the client device can generate the guidance information using the map database including the latest information. . As described above, according to this feature configuration, it is possible to perform route guidance based on the latest map data in the client device while suppressing the communication amount between the server device and the client device.

  As described above, the map database includes road network information. Since the guide route is searched based on the road network information, the difference information can be suitably extracted by extracting the difference along the guide route of each road network information included in each map database. It becomes. That is, as one aspect, the difference information extraction unit of the navigation system according to the present invention includes the road network information included in the server-side map database and the version of the client-side map database indicated by the version specifying information. It is preferable to extract the difference along the guide route from the road network information to be extracted as the difference information.

  The guide route searched based on the road network information can be represented by a link string that is an array of road links constituting the road network information. Therefore, the difference information can be suitably extracted by applying the link sequence constituting the guide route searched using the server side map database to the road network information of the client side map database. In other words, as one aspect, the difference information extraction unit of the navigation system according to the present invention is configured such that the road constituting the guide route searched by the route search unit based on road network information included in the server-side map database. It is preferable to generate a link string indicating an arrangement of links, and extract information on a mismatched portion when the link string is applied to road network information included in the client-side map database as the difference information.

  A user can easily pass through an intersection or a branch point by showing an enlarged view at a guide point such as an intersection or a branch point on the guide route. In addition, if the user can know the landmark facility, the name of the place in the direction of travel on the road, and the name of the place of the guide point at such a guide point, it will be beneficial to pass through intersections and branch points accurately. . Therefore, as one aspect, in the navigation system according to the present invention, it is preferable that the guidance shortage information includes at least one of a guidance point enlarged view, facility information around the guidance point, and guidance name information.

  When the server-side map database version is newer than the client-side map database version, the road network information included in the server-side map database includes new roads that do not exist in the client-side map database road network information. There is a case. Such a new road may be applied as a road constituting the searched guidance route, or may be a connecting road that does not constitute a guidance route but is connected to the guidance route. Depending on the usage of the new road, such as whether the new road is applied as a road constituting the guide route or simply a connection road to the guide route, the information on the new road included in the shortage information for guidance is different. The amount of guidance insufficient information can be reduced. As one aspect, the shortage information generation unit for guidance of the navigation system according to the present invention is included in the difference information when the difference information includes information on the roads constituting the guide route. It is preferable that the shortage information for guidance is generated including information indicating the whole part of the guidance route on the road. On the other hand, when the difference information includes information indicating that there is a connection road connected to the road constituting the guide route, the guidance shortage information generation unit is configured to display the guide route on the connection road. It is preferable that the insufficient information for guidance is generated including information indicating a portion within a predetermined range.

  Various technical features of the navigation system according to the present invention described above can be applied to a navigation program and a navigation method. Therefore, the present invention can also cover such a navigation program and navigation method. For example, the navigation program according to the present invention can cause a computer to execute various functions having the features of the navigation system described above. The typical aspect is illustrated below. Of course, such a navigation program can also provide the above-described operational effects of the navigation system. Furthermore, various additional features exemplified as a preferable aspect of the navigation system can be incorporated into the navigation program, and the program can also provide operational effects corresponding to the respective additional features. The same applies to the navigation method according to the present invention.

In that case, the characteristic configuration of the navigation program according to the present invention is as follows:
A navigation program for causing a plurality of computers to implement a client device having a client-side map database including at least road network information and a server device having a server-side map database of the same version or newer than the client-side map database. And
Search information receiving function for receiving search information including at least a guidance start point and a destination point, and version specifying information that is information that can specify the version of the client side map database;
A route search function for searching for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
Based on the version specifying information, a difference information extraction function for extracting difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database;
Based on the difference information, a guide shortage information generation function that generates information that is insufficient for generating guide information in the client device as guide shortage information,
A search result information transmission function for transmitting search result information including route specifying information that is information that can specify the guide route and insufficient information for guidance to the client device is realized in a computer that constitutes the server device. ,
A search information transmission function for transmitting the search information and the version specifying information to the server device;
A search result information receiving function for receiving the search result information from the server device;
Based on the client side map database and the search result information, a guide information generation function for generating the guide information using the information included in the client side map database and the insufficient information for guidance is configured in the client device. It is in the point to be realized in the computer that does.

The characteristic configuration of the navigation method according to the present invention is as follows.
A navigation method using a client device having a client-side map database including at least road network information, and a server device having a server-side map database of the same version or newer than the client-side map database,
Search information receiving step for receiving search information including at least a guidance start point and a destination point, and version specifying information that is information capable of specifying the version of the client side map database;
A route search step of searching for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
A difference information extraction step for extracting difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database based on the version specifying information;
Based on the difference information, a guide shortage information generating step for generating, as guide shortage information, information that is insufficient for generating guide information in the client device;
A search result information transmitting step of transmitting search result information including route specifying information that is information that can specify the guide route and the shortage information for guidance to the client device;
A search information transmission step of transmitting the search information and the version specifying information to the server device;
A search result information receiving step for receiving the search result information from the server device;
Based on the client-side map database and the search result information, a guide information generating step for generating the guide information using the information included in the client-side map database and the insufficient information for guidance is executed on the client device. It is in point to let you.

Block diagram schematically showing the configuration of the navigation system Flow chart showing an example of operation of the navigation system Diagram showing an example of the structure of a map database The figure which shows an example of the screen display for route guidance The figure which shows an example of the screen display for route guidance The figure which shows an example of the screen display for route guidance Diagram showing an example of a node without a branch and a link connected to the node Diagram showing an example of a node with a branch and a link connected to that node Diagram showing guide route with nodes and links The figure which shows an example of the screen display for route guidance using insufficient information for guidance

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the navigation system 1 according to this embodiment includes a server device 2 and a client device 3. Both devices are configured to be able to communicate with each other via a communication interface unit 28 on the server side and a communication interface unit 38 on the client side, and execute navigation in cooperation with each other. The client device 3 is a device that moves with the user, and the server device 2 is basically a device that is fixedly installed at a predetermined location. For example, the client device 3 is an in-vehicle navigation terminal mounted on a vehicle.

  The client device 3 includes a client-side map database 30 including at least road network information (in the drawing, the database is represented as “DB”). On the other hand, the server device 2 includes the server-side map database 20 that is the same as or newer than the client-side map database 30. The server side map database 20 is also configured to include at least road network information. The server-side map database 20 includes road network information that is the same as or newer than the client-side map database 30.

  As shown in FIG. 1, the server device 2 further includes a server-side navigation calculation unit 22. The server-side navigation calculation unit 22 includes a search information reception unit 23, a route search unit 24, a difference information extraction unit 25, a guidance shortage information generation unit 26, and a search result information transmission unit 27. ing. The client device 3 further includes a self-location specifying unit 31, a client-side navigation calculation unit 32, and a user interface unit 39. The navigation calculation unit 32 on the client side includes a destination setting unit 33, a search information transmission unit 34, a search result information reception unit 35, a guidance information generation unit 36, and a guidance unit 37.

  Hereinafter, the navigation function of the navigation system 1 will be described using the flowchart of FIG. 2, # 2 indicates a function group (step group) executed in the server apparatus 2, and # 3 indicates a function group (step group) executed in the client apparatus 3.

  The destination point setting unit 33 of the client-side navigation calculation unit 32 is a functional unit that sets a search start point and a destination point. For example, the destination setting unit 33 receives a user instruction received by a touch panel or the like provided in the monitor device 5 via the user interface unit 39 and sets the destination (# 33). That is, the destination point setting unit 33 sets a destination point based on a user instruction. As an example, the destination point setting unit 33 sets the current position of the vehicle (the own position specified by the own position specifying unit 31 described later) as the search start point. Note that, similarly to the destination, the search start point may be set based on a user instruction. Of course, as a search start point, the user's own position and a user-set point may be selectable. Information including the destination point and the search start point is transmitted to the server device 2 by the search information transmission unit 34. More specifically, the search information transmission unit 34 transmits search information including at least a guidance start point and a destination point, and version specifying information that is information that can specify the version of the client-side map database 30 to the server device 2 (# 34). At this time, it is preferable that the client device 3 makes a route search request to the server device 2. Alternatively, the client device 3 may make a communication request to the server device 2.

  When there is a route search request or communication request from the client device 3 (# 28), the server device 2 receives the search information and the version specifying information transmitted from the client device 3 (# 23). Of course, it may be set to receive automatically. The search information and the version specifying information are received by the search information receiving unit 23 of the server side navigation calculation unit 22. That is, the search information receiving unit 23 is a functional unit that receives search information including at least a guidance start point and a destination point, and version specifying information that is information that can specify the version of the client-side map database 30. The search information and the version specifying information received by the search information receiving unit 23 are used in the route search unit 24 and the difference information extraction unit 25, respectively. Based on the received search information, the route search unit 24 searches the guide route from the guidance start point to the destination point using the server-side map database 20 (# 24). Moreover, the difference information extraction part 25 extracts the difference information which shows the difference of the information along the guidance route | route of the server side map database 20 and the client side map database 30 based on the received version specific information (# 25). . Here, it is assumed that the version of the server-side map database 20 is higher than the version of the client-side map database 30, and that “No” is determined in step # 25a preceding step # 25.

  As described above, in the navigation system 1 of the present embodiment, the server device 2 and the client device 3 perform navigation in cooperation. Specifically, based on the guidance route searched by the route search unit 24 of the server device 2, the client device 3 generates guidance information and guides the user (details will be described later). However, when the server-side map database 20 is a newer version than the client-side map database 30, the information corresponding to the guide route searched for in the server device 2 does not exist in the client device 3, and the client device guides appropriately. Information may not be generated. Therefore, as described above, the difference information extraction unit 25 extracts difference information indicating a difference in information along the guide route.

  When the difference information is extracted by the difference information extraction unit 25, the guidance shortage information generation unit 26 of the server-side navigation calculation unit 22 generates guidance shortage information based on the difference information (# 26). Here, the insufficient information for guidance is information that is insufficient for the generation of guidance information in the client device 3 (details will be described later). The guidance shortage information is transmitted to the client device 3 by the search result information transmission unit 27. Specifically, the search result information transmitting unit 27 transmits the search result information including the guidance shortage information and the route specifying information that is information that can specify the guide route searched by the route searching unit 24 to the client device. 3 (# 27). At this time, it is preferable for the server device 2 to notify the client device 3 of completion of the route search and a communication request.

  Prior to the extraction of the difference information in step # 25, the version of the server-side map database 20 and the client-side map database 30, particularly the version of the road network information, is the same by the difference information extraction unit 25 or other functional units. It is preferable to determine whether or not (# 25a). The version of the server side map database 20 is the same as the version of the client side map database 30 or a newer version than the client side map database 30. For this reason, when the versions of the server-side map database 20 and the client-side map database 30 are not the same, the server-side map database 20 is a newer version than the client-side map database 30. Therefore, it is preferable that difference information is extracted only in this case. If the versions of the server-side map database 20 and the client-side map database 30 are the same, it is not necessary to extract difference information in step # 25. In this case, since difference information is not extracted, it is not necessary to generate guidance shortage information in step # 26. Therefore, if it is determined in step # 25a that the version of the map database is the same, step # 25 and step # 26 are skipped and the process proceeds to step # 27, where search result information including route specifying information is obtained. It is transmitted to the client device 3.

  The search result information receiving unit 35 of the navigation calculation unit 32 on the client side, when there is a route search completion notification or a communication request from the server device 2 (# 38), the search result transmitted from the server device 2. Information is received (# 35). Of course, it may be set to receive automatically. The received search result information is used by the guidance information generation unit 36. The guidance information generation unit 36 is a functional unit that generates guidance information based on the search result information and the client-side map database 30. Specifically, the guidance information generation unit 36 generates guidance information using information included in the client side map database 30 and insufficient information for guidance based on the client side map database 30 and the search result information (# 36). ). The guide unit 37 guides the user using this guide information (# 37). For example, the guidance unit 37 provides guidance voice or guidance to the monitor device 5 having a speaker or a display unit via the user interface unit 39 based on the guidance information corresponding to the position information specified by the own position specifying unit 31. Output images.

  The own position specifying unit 31 is a functional unit that specifies the own position so that the navigation calculation unit 32 can provide route guidance to the destination and provide various information at the own position. The self-location specifying unit 13 uses surveying by GPS (global positioning system) or autonomous control by Dead-Reckoning using information acquired by the GPS receiver 41, the direction sensor 42, the distance sensor 43, and the like. And calculate and acquire its own position. When the camera is mounted on the vehicle, the self-position specifying unit 31 captures a feature such as a road marking (paint) provided on the road surface and recognizes the image in order to improve the position accuracy. May be further added.

  In the present embodiment, the server device 2 and the client device 3 are configured with an arithmetic processing device such as a microcomputer or a DSP (digital signal processor) as a core member. That is, each functional unit of the above-described navigation system 1 (the server device 2 and the client device 3) includes an arithmetic processing device, a storage medium such as a memory and a disk device, hardware such as a peripheral circuit, and the like on the hardware. It is realized by cooperation with software such as programs and parameters used. Accordingly, each functional unit corresponds to a functional unit in the navigation system of the present invention, corresponds to a “function” in the navigation program of the present invention, and corresponds to an execution unit of “step” in the navigation method of the present invention.

  For example, Step # 33 in FIG. 2 corresponds to the destination setting function in the navigation program of the present invention, and also corresponds to the destination setting step in the navigation method of the present invention executed by the destination setting unit 33. Similarly, step # 34 corresponds to a search information transmission function and also corresponds to a search information transmission step. In step # 34, search information and version specifying information are transmitted, but the names of functions and steps are simplified as in the search information transmission unit 34. Step # 23 corresponds to a search information reception function and a search information reception step, and step # 24 corresponds to a route search function and a route search step. Step # 25 corresponds to a difference information extraction function and a difference information extraction step. Note that step # 25a and step # 25 may be combined to correspond to the difference information extraction function and the difference information extraction step. Step # 26 corresponds to a guidance shortage information generation function and a guidance shortage information generation step, and step # 27 corresponds to a search result information transmission function and a search result information transmission step. Step # 35 corresponds to a search result information reception function and a search result information reception step, step # 36 corresponds to a guidance information generation function and a guidance information generation step, and step # 37 corresponds to a guidance function and a guidance step. It corresponds to.

  Here, the structure of the map database (20, 30) will be described with reference to FIG. Although the server-side map database 20 and the client-side map database 30 may have different versions, their structures are the same. Therefore, the structure will be described below simply by referring to the map database. The map database is a database in which map information M divided for each predetermined area and a plurality of feature information F associated with the map information M are stored. As shown in FIG. 3, the map database includes a road network layer m1, a road shape layer m2, and a feature layer m3.

  The road network layer m1 is a layer including road network information indicating a road connection form. Specifically, information on a large number of nodes N having position information on a map expressed by latitude and longitude, and information on a large number of links K (road links) constituting a road by connecting the two nodes N It is comprised. Each link K has information such as the type of road (type of highway, toll road, national road, prefectural road, etc.) and link length as the link information. The road shape layer m2 is a layer associated with the road network layer m1 and indicating the shape of the road. Specifically, information on a number of road shape complementary points S, road width information, and the like, which are arranged between two nodes N (on the link K) and have position information on a map expressed in latitude and longitude. It is configured. The map information M is configured by the information stored in the road network layer m1 and the road shape layer m2.

  The feature layer m3 is configured in association with the road network layer m1 and the road shape layer m2, and is a layer in which information of various features provided on the road and around the road, that is, the feature information F is stored. is there. The feature in which the feature information F is stored in the feature layer m3 includes a road marking provided on the road surface. Such road markings include lane division markings such as a roadway center line, a roadway boundary line, a roadway outer line, and a zebra zone that divide lanes. In addition, road markings include, for example, pedestrian crossings, stop lines, intersection shape markings (cross marks, T-shaped marks, etc.), arrow-shaped road markings indicating the traveling direction of each lane in the traveling direction, and speed markings indicating speed limits Various kinds of paint markings are included. Note that the features in which the feature information F is stored may include various three-dimensional objects such as traffic lights, signs, overpasses, and tunnels in addition to plane objects such as road markings.

  Incidentally, as described above, the guide information generation unit 36 of the client device 3 generates guide information based on the search result information received from the server device 2 and the client-side map database 30. And the guidance part 37 outputs a guidance audio | voice, a guidance image, etc. to the monitor apparatus 5 provided with the speaker and the display part via the user interface part 39 using this guidance information, and guides a user. Here, an example of guidance by the guidance unit 37 is shown.

  FIG. 4 shows an example of a screen displayed on the monitor device 5. There is an intersection with a traffic light in the traveling direction of the vehicle icon 90 indicating the vehicle on which the user has boarded. Three road segments (lanes) are provided on the road on which vehicles pass at this intersection. The navigation system 1 informs the user of lanes that can be traversed among the three lanes when guiding a straight path at this intersection. In the example shown in FIG. 4, a traffic signal icon 81 indicating that an intersection has a traffic signal is displayed on the intersection, and a lane icon 82 indicating three traffic sections is displayed in the vicinity thereof. Then, two lane icons 82a and 83b including a straight traveling direction are cooperatively displayed as lanes through which the vehicle can pass. The traffic light icon 81, the lane icon 82, etc. are examples of guidance images. Furthermore, it is preferable that the user is provided with a guidance message such as “Please pass the left two lanes” as voice guidance.

  Information indicating the presence of such a traffic signal is stored, for example, in the feature layer m3 of the map database. Moreover, the information which shows the kind and aspect of a traffic classification is stored in the road shape layer m2 and the feature layer m3 of a map database. The information of the traffic light icon 81, the lane icon 82, and the guidance message may be stored in the road shape layer m2 or the feature layer m3, or stored in an icon layer (not shown) provided separately from these. May be.

  5 and 6 show an example in which the screen of the monitor device 5 is divided to display two screens, and an enlarged view of an intersection or the like is displayed on one screen. In this example, the screen of the monitor device 5 is divided into left and right, a road map is displayed on the left screen, and an enlarged view of the road at the guide point (intersection) and various icons are displayed on the right screen. FIG. 5 shows an example of guiding a right turn at an intersection having a complicated structure. Here, an example in which a traffic signal icon 81 and a route guidance icon 83 are displayed is shown. FIG. 6 shows an example of guiding a route change from a main road of a highway to a deceleration lane toward a general road or a toll gate, for example.

  4 to 6 is implemented so that the vehicle can be guided along the guide route when the road is branched and the vehicle can take a plurality of routes. That is, when the vehicle can take only a single route, there is almost no possibility of deviating from the guidance route, and thus such guidance is not performed. For example, as shown in FIG. 7, when a vehicle traveling on the link Ka is set as a guide route through the node Na to the link Kb, the vehicle takes only a single route at the node Na. I don't get it. In such a case, guidance as illustrated in FIGS. 4 to 6 is not performed when the vehicle approaches the node Na. On the other hand, as shown in FIG. 8, when the vehicle traveling on the link Ka can select a plurality of routes of the links Kb, Kc, Kd via the node Na, the vehicle proceeds to the link Kb along the guide route. The guidance as illustrated in FIGS. 4 to 6 is performed so that it can be performed.

  Hereinafter, a specific example in which the client device 3 guides the guide route searched by the server device 2 when the version of the server-side map database 20 is newer than the version of the client-side map database 30 will be described. The guide route searched by the route search unit 24 of the server device 2 is represented by a node N and a link K as shown in FIG. Nodes N (N0 to N8) are represented by hollow circles, and links K are represented by line segments connecting the nodes N. Here, the number of the node N is used, and for example, the link K between the node N1 and the node N2 is represented as a link K12. In FIG. 9, the guidance start point Q and the destination point P are represented by black circles. Similarly to the node N, the guidance start point Q and the destination point P also have position information on the map expressed by latitude and longitude. The guidance start point Q and the destination point P are set in the middle of the link K in this example. In FIG. 9, a link K indicated by a thick line indicates a guide route connecting the guide start point Q and the destination point P searched by the route search unit 24 of the server device 2.

  By the way, as described above, the version of the server-side map database 20 is equal to or higher than the version of the client-side map database 30. That is, the server-side map database 20 will be described as an example in which it has new road network information that the client-side map database 30 does not have.

  Specifically, links K35, K28, and K59 shown in FIG. 9 are newly opened roads (new roads), and the client-side map database 30 stores the new road network information and related feature information. I don't have it. Therefore, if a guide route is searched using a map database of the same version as the client-side map database 30, as shown by a thin solid line in FIG. 9, the node N3 passes through the node N4 to reach the node N5. The route is searched as a guide route. Further, in the information stored in the client side map database 30, there is no road branch at the node N2. Further, the client-side map database 30 does not store information on the link K28 indicated by a broken line, road shape information or feature information at the node N2. Therefore, there is a possibility that the guidance information in the vicinity of the node N2 is insufficient and the convenience for the user is lowered. Further, for the link K35 that is a new road constituting the guide route, guide information cannot be generated using the information in the client-side map database 30. For this reason, the search result searched using the latest road network information cannot be used effectively.

  In the navigation system 1 of the present embodiment, in order to suppress such a decrease in convenience, the difference information extraction unit 25 of the server device 2 follows the guidance route between the server-side map database 20 and the client-side map database 30. The difference information indicating the difference between the information is extracted. That is, as described above with reference to the flowchart of FIG. 2, it is first determined whether or not the map version of the server side map database 20 and the client side map database 30 are the same (# 25a). If the versions are different, the difference information is extracted by the difference information extraction unit 25 because the server-side map database 20 is a newer version (# 25).

  Hereinafter, an example of a procedure for the difference information extraction unit 25 to extract difference information will be described. The guidance route searched by the route search unit 24 can be expressed as a link string as shown below, for example. The link string indicates an array of road links constituting the guide route searched by the route search unit 24 based on the road network information included in the server-side map database. The link string is generated by the route search unit 24 or the difference information extraction unit 25. The link row is an arrangement of links K from the guidance start point Q to the destination point P, most simply as “K01-K12-K23-K35-K56-K67”, taking the guidance route shown in FIG. 9 as an example. Indicated by. The link string may be configured by adding, for example, a node N having a branch to such a basic array to the link string. For example, a node N having a branch is added to form a link string such as “K01-K12-N2-K23-N3-K35-N5-K56-K67”. Such a link string is transmitted as route specifying information from the server device 2 to the client device 3 and used by the guide information generating unit 36 of the client device 3. The guidance information generation unit 36 determines that route guidance is necessary at the nodes N2, N3, and N5 from the link string, and generates guidance information.

  On the other hand, the difference information extraction unit 25 evaluates such a link string based on version specifying information for specifying the version of the client-side map database 30. That is, the information on the mismatched portion when the link string is applied to the road network information included in the client-side map database 30 is extracted as difference information. For example, it is assumed that the version number of the server-side map database 20 is 3.0 and the version number of the client-side map database 30 is 1.2. Here, the integer part of the version number indicates the version of major update (large-scale update), and the decimal part indicates the version of minor update (small-scale update). The larger the version number including the decimal part, the newer the version. In order to use for the evaluation of the link string, it is preferable that the version information in which the information of each node N and link K is updated is added and stored in the map database as the attached information of each node N and link K. . Alternatively, the server apparatus 2 may be provided with a difference database in which the nodes N and links K in each version are listed.

  The difference information extraction unit 25 determines whether or not the node N and the link K included in the link sequence are included in the client-side map database 30. In the present embodiment, it is determined that the link K35 that is a new road is not included in the client-side map database 30. For example, it is assumed that the version number 2.0 in which the link K35 is added to the road network information is stored as the attached information of the link K35. Since this version number 2.0 is larger than the version number 1.2 of the client side map database 20, it is determined that the link K35 is a new road. Nodes N2, N3, and N5 are nodes N in the client-side map database 30 where two links K are connected to the node N, but three or more links K are connected in the link sequence of the guide route. Node N with the branch to be made. Therefore, these N2, N3, and N5 are also determined to be nodes N having different connection information from the client-side map database 30.

  Next, the difference information extraction unit 25 extracts information about the node N and the link K updated from the client-side map database 30 as difference information. For example, for the link K35, the road itself corresponding to the link K does not exist in the client-side map database 30. Therefore, the difference information extraction unit 25 generates insufficient information for guidance including at least information indicating the entire part constituting the guidance route. That is, since the link K35 is the entire part of the guide route on the newly opened road, the guidance shortage information including the information indicating the entire link K35 is generated. On the other hand, the link K59, which is a new road, is a connecting road (link K) connected to the node N5 included in the link K35 constituting the guide route, and is not a road constituting the guide route. Therefore, in the link K59 which is a connection road, guidance shortage information including information indicating a portion within a predetermined range from the guide route (within a predetermined range from the node N5) is generated.

  The predetermined range is preferably set to a range in which the connection road can be displayed without a sense of incongruity on the map displayed on the monitor device 5 at a normal scale. For example, when a square grid such as 16 × 9 is provided on the map displayed on the monitor device 5 and the length of one side of each grid is about 50 m to 500 m, the connecting road is interrupted in the middle. The range displayed on the display surface of the monitor device 5 can be used without any problem.

  By the way, the nodes N3 and N5 are nodes N to which a newly opened road (link K35) is connected after road network information is stored in the client-side map database 30, respectively. It has become. In addition, a new road (link K28 indicated by a broken line) that does not constitute a guide route is connected to the node N2 as a connection road. For this reason, the node N2 is also a node N having a branch. Therefore, branch information at these nodes N2, N3, and N5, an enlarged view of the guide point at the branch, facility information (feature information) around the guide point, name information for guidance, and the like are generated as insufficient information for guidance. The For the link K28 which is a connection road, insufficient information for guidance is generated including information indicating a portion within a predetermined range from the guide route (within a predetermined range from the node N2).

  As described above, when the information on the roads constituting the guide route is included as the difference information, the guidance shortage information generation unit 26 indicates the portion constituting the guide route on the road included in the difference information. Insufficient information for guidance is generated including information indicating the whole. In addition, when the information for indicating that there is a connecting road connected to the road constituting the guide route is included as the difference information, the guidance shortage information generating unit 26 determines the predetermined information from the guide route on the connected road. Insufficient information for guidance is generated including information indicating a portion within the range. The guidance shortage information is information including at least one of a guidance point enlarged view, facility information around the guidance point, and guidance name information. Specific examples thereof will be described later together with an example of a display screen of the monitor device 5.

  As described above, the generated guidance shortage information and the guidance route are transmitted from the search result information transmitting unit 27 to the client device 3 and received by the search result information receiving unit 35. The guide information generating unit 36 generates guide information based on the received guide shortage information and the guide route. For example, the guidance information generation unit 36 generates guidance information for performing branch guidance that proceeds to the right road in the vicinity of the node N2. Further, in the road map displayed on the monitor device 5, at least a part of the link K28 that is a connection road to the node N2 is displayed.

  FIG. 10 is similar to the display screen illustrated in FIG. 5 and FIG. 6, the screen of the monitor device 5 is divided to display a road map on the left screen, and an enlarged view of the road at the guide point (intersection) on the right screen. This is an example in which various icons are displayed. The guide information generation unit 36 generates guide information using the guide shortage information in addition to the information included in the client-side map database 30. In the road map on the left screen, the drawing information of the road corresponding to the link K28 is provided as insufficient information for guidance, and the guide unit 37 displays the road map on the monitor device 5 using this drawing information. Thereby, the user can match an actual scenery and a road map without a sense of incongruity. Further, an enlarged view of the node N2 is displayed on the right screen. This enlarged view, that is, the enlarged guide point view, is provided as insufficient information for guidance. The traffic light icon 81, the lane icon 82, and the facility icon 84 indicating a supermarket displayed on the right screen are provided as insufficient information for guidance corresponding to facility information around the guidance point. A destination display icon 85 indicating a destination at a branch is provided as guidance shortage information corresponding to guidance name information. The guidance name information includes an intersection name, a road name, and the like.

  The guidance information generation unit 36 guides the user about the lane corresponding to the traveling direction along the searched route when the guidance shortage information includes a dynamically displayable icon such as the lane icon 82. Generate information. For example, in order to proceed to the road corresponding to the link K23, it is preferable to highlight the lane icon 82d indicating the right turn lane. In accordance with this, it is preferable to generate a voice message such as “Go right lane and turn right” as the guidance information.

  The same applies to the shortage information for guidance in the vicinity of the nodes N3 and N5, the generation of guidance information using the shortage information for guidance, the display form on the monitor device 5 and the like, and detailed description thereof will be omitted. For the link K35, which is a new road included in the guide route, all the information on the link K35 is provided as insufficient information for guidance. Therefore, the road map is displayed in a state that matches the actual scenery, and facilities and place names around the road corresponding to the link K35 can be displayed on the monitor device 5, so that the user can use the navigation system 1 without a sense of incongruity. Can be used.

  As described above, when the server-side map database 20 and the client-side map database 30 have different versions, the navigation system 1 does not calculate the difference between the two map databases and eliminate the difference between the map databases. . Therefore, it is not necessary to perform a calculation in the server device 2 to obtain the difference of the entire map database. Also, the client device 3 does not need to perform an operation for updating the client-side map database 30 in order to eliminate the difference. On the other hand, in the navigation system 1, in the range along the guidance route connecting the guidance start point and the destination point, information that is insufficient to generate guidance information using the client-side map database 30 is generated as guidance shortage information. And transferred. Therefore, the calculation load in the server device 2 is greatly suppressed as compared with the case of obtaining the difference of the entire map. In addition, since the guidance shortage information is also information in a range along the guidance route, the capacity thereof is relatively small, and the communication amount is greatly suppressed as compared with the case where the difference of the entire map is transferred. Also, the client device 3 does not require computation for updating the client side map database 30. And since the client apparatus 3 only refers to the shortage information for guidance in addition to the client side map database 30 when generating the guidance information, the calculation load is hardly increased.

  In the above-described embodiment, the route search unit 24 searches for a guide route using only the server-side map database 20. That is, when extracting the difference information, the server device does not necessarily need to search for a guide route based on the client-side map database, so that the calculation load is suppressed and a quick route search is possible. For example, as in Patent Document 1, when the server device searches for two routes (guide routes) of a first route (guide route) and a second route (guide route), the computation load increases, and the route becomes large. Search time may be longer. However, in the above-described embodiment, the information that can be acquired from the server-side map database 20 along the searched guidance route and the version-specific information that can be acquired from the client-side map database 30 along the guide route. Only the difference information indicating the difference from the determined information is extracted. That is, since the second route (guide route) is not searched, the calculation load is suppressed, and a quick route search becomes possible. That is, the navigation system 1 can promptly perform route guidance based on the latest map data in the client device 3 while suppressing the amount of communication between the server device 2 and the client device 3.

[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of other embodiments as long as no contradiction arises.

  In the above embodiment, the route search unit 24 searches for the guide route using only the server-side map database 20, and the difference information extraction unit 25 uses the version specifying information to find the difference in information along this search route. The example which extracts the difference information which shows is illustrated. However, without being limited to this form, the route search unit 24 further searches for the second guide route to be compared using the road network information corresponding to the client-side map database 20 based on the version specifying information. May be. And the difference information extraction part 25 may compare the guidance route searched using the server side map database 20, and a 2nd guidance route, and may extract difference information. Of course, in this embodiment, since the server device 2 searches for two guide routes, the calculation load on the server device 2 increases. However, when the increase in calculation load is permitted, this form can also be taken.

  The present invention can be applied to a server-client type navigation system capable of searching for a route using the latest map data of the server device.

1: Navigation system 2: Server device 3: Client device 20: Server-side map database 23: Search information receiving unit 24: Route search unit 25: Difference information extracting unit 26: Shortage information generating unit for guidance 27: Search result information transmitting unit 30: Client-side map database 34: Search information transmitting unit 35: Search result information receiving unit 36: Guide information generating unit 37: Guide unit 38: Communication interface unit 39: User interface unit K: Link (road link)
P: destination point Q: guidance start point

Claims (7)

A navigation system comprising: a client device having a client-side map database including at least road network information; and a server device having a server-side map database of the same version or newer than the client-side map database,
The server device is
A search information receiving unit for receiving search information including at least a guidance start point and a destination point, and version specifying information which is information capable of specifying the version of the client side map database;
A route search unit that searches for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
Based on the version identification information, a difference information extraction unit that extracts difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database;
Based on the difference information, a guide shortage information generating unit that generates information that is insufficient for generating guide information in the client device as guide shortage information;
A search result information transmitting unit that transmits search result information including route specifying information that is information that can specify the guide route and insufficient information for guidance to the client device,
The client device is
A search information transmitting unit for transmitting the search information and the version specifying information to the server device;
A search result information receiving unit for receiving the search result information from the server device;
A navigation system comprising: a guide information generating unit that generates the guide information using information included in the client-side map database and the insufficient information for guidance based on the client-side map database and the search result information.   The difference information extraction unit calculates a difference along the guidance route between the road network information included in the server-side map database and the road network information included in the client-side map database of the version indicated in the version specifying information. The navigation system according to claim 1, wherein the difference information is extracted as the difference information.   The difference information extraction unit generates a link string indicating an array of road links constituting the guide route searched by the route search unit based on road network information included in the server-side map database, and the link string The navigation system according to claim 2, wherein information on a disagreement portion is extracted as the difference information when is applied to road network information included in the client-side map database.   The navigation system according to any one of claims 1 to 3, wherein the insufficient information for guidance includes at least one of an enlarged map of guidance points, facility information around the guidance points, and name information for guidance.   When the information for a road that constitutes the guide route is included as the difference information, the shortage information generation unit for guidance includes the entire portion that constitutes the guide route on the road included in the difference information. If the information indicating that there is a connection road connected to the road constituting the guide route is included as the difference information, the connection shortage information is included. The navigation system according to claim 1, wherein the guide shortage information is generated including information indicating a portion within a predetermined range from the guide route. A navigation program for causing a plurality of computers to implement a client device having a client-side map database including at least road network information and a server device having a server-side map database of the same version or newer than the client-side map database. And
Search information receiving function for receiving search information including at least a guidance start point and a destination point, and version specifying information that is information that can specify the version of the client side map database;
A route search function for searching for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
Based on the version specifying information, a difference information extraction function for extracting difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database;
Based on the difference information, a guide shortage information generation function that generates information that is insufficient for generating guide information in the client device as guide shortage information,
A search result information transmission function for transmitting search result information including route specifying information that is information that can specify the guide route and insufficient information for guidance to the client device is realized in a computer that constitutes the server device. ,
A search information transmission function for transmitting the search information and the version specifying information to the server device;
A search result information receiving function for receiving the search result information from the server device;
Based on the client side map database and the search result information, a guide information generation function for generating the guide information using the information included in the client side map database and the insufficient information for guidance is configured in the client device. A navigation program that can be implemented on a computer. A navigation method using a client device having a client-side map database including at least road network information, and a server device having a server-side map database of the same version or newer than the client-side map database,
Search information receiving step for receiving search information including at least a guidance start point and a destination point, and version specifying information that is information capable of specifying the version of the client side map database;
A route search step of searching for a guide route from the guidance start point to the destination point using the server-side map database based on the search information;
A difference information extraction step for extracting difference information indicating a difference in information along the guide route between the server-side map database and the client-side map database based on the version specifying information;
Based on the difference information, a guide shortage information generating step for generating, as guide shortage information, information that is insufficient for generating guide information in the client device;
A search result information transmitting step of transmitting search result information including route specifying information that is information that can specify the guide route and the shortage information for guidance to the client device;
A search information transmission step of transmitting the search information and the version specifying information to the server device;
A search result information receiving step for receiving the search result information from the server device;
Based on the client-side map database and the search result information, a guide information generating step for generating the guide information using the information included in the client-side map database and the insufficient information for guidance is executed on the client device. Navigation method to let you.

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