Matsushita Electric Industrial Co., Ltd.

Yasuhiro Ihara

Yoshiki Ueyama

Akihiro Suzuki

Nobuyuki Nakano

Hisaya Fukuda

Mitsuhiro Yamashita

Takeshi Yagyu

A terminal device for reading a cartographic file in which updating one cartographic file does not require updating cartographic files in the neighboring units. For this purpose, cartographic files which represent respective units extracted by dividing a map into a plurality of areas each comprise node records generated for respective nodes and link records generated for respective links. Given node records contain coordinate information about neighboring nodes which define connections of roads between its unit and a neighboring unit. The cartographic files are stored in a first storage device. The data processing portion executes a process of searching for a route by using the cartographic files. During the route search, the data processing portion traces the connection from a road in one unit to a road in another, neighboring, unit on the basis of the coordinate information about the neighboring nodes of said one unit and said neighboring another unit.

Data structure of digital map file

In an information terminal device, a processor receives route information on a route from a start point to a destination and guidance information required for route guidance, in accordance with a standard communications protocol. The processor guides the route from the start point to the destination through an information presentation part by using first cartographic data having a basis on the received route information and the guidance information. The processor requests, as required, a specific information service center for point information in a tag format showing details of each important point (POI) on the route through an information request part. As a result, the processor receives the point information on the important point from the information service center in accordance with the standard communications protocol. The processor presents the received point information on the important point simultaneously with a map based on the first cartographic data to clearly indicate each of the important points on the route. With the aid of the tag format, the information terminal device is capable of receiving, using the standard communications protocol, various information in the suitable format for the route guidance.

Information terminal device and method for route guidance

An object is to realize a server/client-type map information providing system capable of providing detailed, wide-ranging map related information through telecommunications at low costs, and a server side is provided with databases (,to,) storing the map related information. When notified of position information from a mobile terminal side, a processing portion,performs a route search referring to map data in the map database,based on the position information. The processing portion,then extracts Information related to the obtained route (route related information) from the databases (,to,) to transmit the information with the route to the mobile terminal side. In this way, since the mobile terminal side needs only the information that is closely related to the route in the map related information, only the route related information is transmitted, thereby reducing the amount of information to be transmitted compared to that when the map related information is downloaded as it is, and as a result it is possible to provide detailed, wide-ranging map related information through telecommunications at low costs.

System, method, and computer program for providing map information from a server to movable terminals

Road map information used in a vehicle navigation or the like is classified into main road groups comprising roads having a high frequency of utilization for route searching processing or the like and minor street groups comprising roads having a low frequency of utilization. Information relating to the roads belong to the main road group are recorded in such a format that the processing speed precedes reduction of a capacity required for recording. On the contrary, information relating to the roads belonging to the minor street group are recorded in such a format that a reduction of a capacity required for recording precedes the processing speed. The minor street group is divided into a plurality of arbitrary small groups to decrease the range of minor streets requiring information to the utmost in the route searching processing or the like. Further, one road which can be represented with one stroke of the brush and roads branching from the road are recorded upon being integrated as one group. Consequently, it is possible to realize a road map information readout apparatus in which the recording efficiency of the road map information is increased, thereby reducing the amount of information to be recorded.

Road map information readout apparatus, recording medium and

Road network data is divided into a plurality of road network areas and one or a plurality of routes are obtained between the divided road network areas. The obtained routes are stored into a route data storage device 1. When a starting point and a destination are specified from a point input device 2, an area investigating device 3 investigates two road network areas to which the points belong. A route retrieving device 4 retrieves the route data corresponding to the combination of the obtained two road network areas from the route data storage device 1. A peripheral route searching device 8 searches for connecting routes in the road network areas to which the starting point and the destination belong, on the basis of the road network data stored in the road network data storage device 7. Further, the peripheral route searching device 8 produces the entire route from the starting point to the destination by using the route data retrieved from the route data storage device 1 and the connecting routes searched for in the vicinities of the starting point and the destination and presents the route to a user through an output device 6. This way, routes between arbitrary two road network areas are obtained in advance and stored as route data. When a starting point and a destination are specified, the route data between the corresponding road network areas are retrieved and a route from the starting point to the destination is presented on the basis of the retrieved route data. Thus the route can be searched for in an instant.

Method and apparatus for searching a route

A map searching unit reads from a map storing unit map data adjacent to the current position of a vehicle calculated by a position calculator or map data having a range of a map to be displayed specified by an input unit. A processing unit performs a perspective transformation of eye point and focus point coordinates inputted from the input unit, maps the map data on the transformed coordinates, performs clipping, and then makes an output unit display the map after mapping.

Automotive navigation apparatus and recording medium storing program

A correct vehicle position is detected even when the road data to be used in the map match computation includes errors of partial shape. When the matching computing operation of a running locus and the road data obtained from the outputs of a bearing sensor and a distance sensor and a non-match region has been effected by the map match computing means, the non-matching region of the road data and the running locus is detected. The positional error detection caused by errors of the road data is effected by prohibiting map integration.

Vehicle position detecting apparatus which comensates for errors in road

Vehicle position detecting apparatus

The direction of a terrestrial magnetism is detected by a terrestrial magnetism sensor mounted on a vehicle, and an output circle is generated on an X-Y coordinate by turning the vehicle on the ground, when the vehicle passes through a foreign magnetic fields the direction of the foreign magnetic field is detected by the terrestrial magnetism sensor, and the course thereof is determined on the basis of former output circle before passing through the foreign magnetic field and the output of an angular velocity sensor of the vehicle after passing it, then a new center of the output circle is determined by evaluating an intersection of the line representing the foreign magnetic field and the line representing the course of the vehicle on the X-Y coordinate.

Magnetic direction finder with correcting circuit

The direction finding apparatus provided in the vehicle (10) computes average data and variance data from output data of the terrestrial magnetism sensor (1) in straight moving, and determines reliability of the detected output data of the terrestrial magnetism sensor (1). The error due to the magnetization of the vehicle (10) is corrected by computing the examined data on each of plural center candidates and selecting a center candidate as a new center coordinate of the present output circle of the terrestrial magnetism. Then, the magnetization of the vehicle (10) is inferred from the new center coordinate, thereby to infer a precise terrestrial magnetism direction.

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Walled Lake, Japan

Yasuhiro Ihara