Data processing: vehicles – navigation – and relative location – Navigation
Reexamination Certificate
1999-03-18
2001-01-23
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
C701S210000, C340S995190
Reexamination Certificate
active
06178377
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a system for transmitting desired information to a terminal from an information center in response to a request from the terminal, and more particularly to a facility information provider system for providing information regarding a certain facility.
The present invention further relates to a position information provider system and a position information provider apparatus for recognizing absolute positions as position data relative to roads.
BACKGROUND ART
Heretofore, navigation apparatuses are known as apparatuses for route guidance in vehicles. These navigation devices basically function by continuously detecting a present position and displaying it on a map. They contain a GPS (global positioning system) apparatus for detecting the present position and a map database for storing map data. Furthermore, by entering a destination, the navigation apparatus searches for an optimum route from the present position and also guides the vehicle in a set travel route in the direction of movement at branch points.
Systems have also been proposed for connecting a mobile terminal, such as in a vehicle, with an information center, and obtaining information necessary in the vehicle. According to this type of system, restaurant information, sightseeing information, locations of usable parking lots, route guidance services to destinations, and so forth can be obtained as needed at the vehicle. The positions of and routes to restaurants, sightseeing spots, parking lots, and so forth can also be displayed on maps.
For example, a system is disclosed in Japanese Patent Laid-Open Publication No. Hei 7-72234 in which position information of a parking lot is returned as latitude and longitude data from an information center when information regarding the parking lot is requested from a terminal carried in a vehicle, and the position of the parking lot is displayed on a map contained in the terminal.
However, according to the apparatus of this publication, there is a problem where the displayed parking lot position based on the received latitude and longitude data is not a proper position on the map since the map contained in the terminal includes error. Namely, the origin material differs in creating the map or a certain amount of error is generated among a plurality of maps having different creation methods or precision. For this reason, a positional relationship with the peripheral condition (such as peripheral roads) of one point specified on one map may differ from a positional relationship with peripheral roads of the corresponding point on another map.
For example, even when a point specified by latitude and longitude is positioned on the right side of a road on one map, a situation may arise where it is indicated on the left side of the road on another map. Therefore, a situation may arise where the positional relationship with the peripheral roads may be incorrectly recognized at the vehicle, such as for a position of a parking lot specified by the information center.
To prevent this phenomenon, a method has been considered for specifying a point with respect to a map by a relative positional relationship with respect to roads (links). For example, this method (tentatively referred to as a relative positioning method) specifies a link by a link number, specifies the distance on the link from the starting point, and further specifies the direction and distance from the starting point. In this manner, by specifying the point as a relative positional relationship, breakdowns in the positional relationship of the road and the point to be specified can be prevented. Note that the links are organized in units of roads separated by intersections, and the road network is expressed as connections of these links in the map database.
The relative positioning method herein assumes that the link numbers at the vehicle and at the information center have identical definitions. However, due to differences in source materials and update times, there are instances where a link specified at the side executing a command does not exist. Furthermore, when there are differences in map precision, a link specified at the information center may not exist at the vehicle. In this instance, a problem is that it might not be possible to specify a point at the receiving side.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a position information provider system capable of displaying the position (specific position), such as of a facility for which information was requested, at an appropriate position on a map.
The present invention uses landmarks, such as of road networks, on map displays that are common to the map database of the information center and to the map database of the terminal so as to correct displacements between the two map databases. The specific position (facility position) to be the information provided is set as a relative position with a landmark on the above-mentioned map in the map database of the information center, and correcting the displacement as described above enables the above-mentioned specific position to be displayed on the map at the terminal with the same positional relationship as on the map at the information center.
Therefore, when the relative position of the above-mentioned landmark and the above-mentioned specific position is displayed on the map at the terminal, an improper display can be prevented.
For example, if the above-mentioned landmark is a road and the above-mentioned specific position (facility) is on the right side of the road according to the map at the information center, the display of the facility on the map at the terminal on the opposite side, or on the left side of the road, can be prevented. Therefore, a problem can be prevented in which a facility, thought by the driver to be on the left side of the road on the map, appears on the right side. In the relative position with the above-mentioned landmark, problems arise, such as the above-mentioned facility being incorrectly displayed on the opposite side of the road, and besides the above-mentioned road, a railroad track, a river, a coastline, and so forth are landmarks. In the case of a river, which can be crossed only at a bridge, if a facility is displayed on the opposite side of its actual position and the destination is incorrect, the bridge must be crossed in order to return to the correct position and much time will be wasted. A similar situation occurs for a railroad track. In the case of a coastline, there is the possibility of having an unnatural display in which the facility to be the destination is shown in the middle of the ocean. Extracting from the landmarks on the map display can prevent such improper displays described above.
Furthermore, the information regarding the above-mentioned landmark can be made to include the shape and type of the relevant landmark. An example of landmark type for roads is the route number or name to specify a road, such as national route 1 or Keihin route 3. On the basis of information on type, the number of landmarks to be searched by shape can be reduced and processing in a short time becomes possible.
Furthermore, the above-mentioned terminal transmits the type of map database held in the relevant terminal, and the above-mentioned position information generating means extracts the above-mentioned landmark in accordance with the received type of map database and generates position information.
According to this configuration, from the information stored in the map database held in the terminal, such as that indicating the degree of detail of the map, the information center can provide information regarding the facility on the basis of map information according to the degree of detail of this map. For example, if the roads stored in the map database of the terminal are only highways, the information center extracts from the map database the highway found in the periphery of the facility as the peripheral landmark, and if local roads, such as municipal roads, are also stored in the terminal
Ishihara Fuminari
Kanemitsu Hiroyuki
Nguyen Tan
Pillsbury Madison & Sutro LLP
Toyota Jidosha & Kabushiki Kaisha
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