Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2001-12-03
2002-10-15
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C073S17800T, C340S990000, C340S995190, C701S200000
Reexamination Certificate
active
06466866
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a technology for calculating a recommended route from a starting point to a destination, and suggesting it to a user in an on-board navigation device or the like.
BACKGROUND OF THE INVENTION
In an on-board navigation device, a technology (a route guidance) has been already put into a practical use, which searches a recommended route from a set starting point to a set destination based on road map data, and guides a vehicle to reach the destination on the recommended route by using a display device, a voice output device and the like.
In the route guidance technology, all routes connecting the set staring point with the set destination are searched by using road map data, and a technology called a dijkstra method searches for a route of minimum cost (for example, the gross distance of the route), thereby setting the searched route as the recommended route. And, for example, the set recommended route is displayed while overlapping a displayed map, and information to be required (for example, information such as whether or not to turn the next intersection) for a vehicle to run on the recommended route is informed via voice. In a case when the vehicle deviates from the recommended route during the route guidance, a recommended route to the destination is searched again, taking the current position of the vehicle as a starting point, and the re-searched route is newly set as the recommended route (an auto-rerouting).
In addition, in an on-board navigation device, in order to position a vehicle on a road in a displayed map, a technology (a map matching) has already been put into a practical use, wherein the current position of the vehicle, determined by various kinds of sensors such as gyro, a running vehicle speed sensor and the like, or GPS receiver, is corrected every specified running distance (for example, 20 meters).
In this map matching technology, the current position of the vehicle, determined by various kinds of sensors such as the running vehicle speed sensor, a gyro or the like, and a GPS receiver, is regarded as a center. Then, all positions corresponding to the current position on the road within a specified range are registered as candidate positions, the specified range being set by the searched current vehicle position, errors included in a traveling direction, and errors of road map data. Then, a current vehicle position is corrected to a candidate position which has the strongest correlation with the current position, in consideration for a distance from a current position to the candidate position; a difference between a vehicle traveling direction, searched by various kinds of sensors such as the vehicle speed sensor, the gyro or the like and the GPS receiver or the like, and a azimuth of road in which a candidate position is set; and a road having the current position of the vehicle corrected by the previous map matching.
DISCLOSURE OF THE INVENTION
Incidentally, in the on-board navigation apparatus to which the foregoing map matching technology is applied, in the case where the plurality of candidate positions are registered, the current position corrected by the map matching at this time is set on a road different from the road with the current position corrected by the previous map matching being set therein (a so-called position skipping). Hereinbelow, a description will be made for this position skipping phenomenon with reference to drawings.
FIG. 5
is a view for explaining the position skipping phenomenon in the on-board navigation apparatus to which the map matching technology is applied. Here, FIG.
5
(
a
) shows an actual road, and FIG.
5
(
b
) shows a shape of a road determined by the road map data corresponding to the road shown in FIG.
5
(
a
).
Now, in FIG.
5
(
a
), it is assumed that the vehicle changes a lane before a junction A and goes straight, then the map matching is performed immediately after the vehicle passes the junction A. In this case, according to the foregoing map matching technology, a position B on a main lane and a position C on a branch lane, which are shown in FIG.
5
(
b
), are registered as candidate positions, both having strong and uncomparable correlations with the current position of the vehicle determined by various kinds of sensors such as a vehicle speed sensor and a gyro, or a GPS receiver and the like. However, when a difference between a traveling direction of the vehicle, searched by the various kinds of sensors such as the vehicle speed sensor and the gyro, or the GPS receiver and the like, and an azimuth of each road in which the candidate position is set is considered, there is a strong possibility that not the candidate position on the branch lane where the vehicle actually runs but the candidate position B on the main lane is selected as a current position after correction.
Here, it is assumed that the current position is corrected to the candidate position B by the map matching, further the vehicle runs thereon. Then, it is assumed that map matching is performed when the vehicle reaches a point D on the branch lane. Also in this case, a position E on the main lane and a position F on the branch lane, which are shown in FIG.
5
(
b
), are registered as candidate positions. However, in consideration for a distance from the current position of the vehicle to the candidate position thereof, which is determined by the various kinds of sensors such as the vehicle speed sensor and the gyro or the GPS receiver and the like; or for a difference between the traveling direction of the vehicle, determined similarly to the above by the various kinds of sensors such as the vehicle speed sensor and the gyro or the GPS receiver and the like, and an azimuth of each road where the candidate position is set, there is a strong possibility that the candidate position F on the branch lane is selected as a current position after correction.
Here, if it is assumed that the current position is corrected to the candidate position F by the map matching, the current position being displayed on the display device is suddenly skipped from the main lane onto the branch lane at the point D. This position skipping phenomenon has a possibility of continuing until a relative distance between the main lane and the branch lane or a difference in shapes between the main lane and the branch lane are made apparent.
Now, when the route guidance technology equipped with the above-described auto-rerouting function is further applied to the on-board navigation apparatus to which the map matching technology involving the position skipping phenomenon as described above is applied, a problem to be described below occurs.
Now, in FIGS.
5
(
a
) and
5
(
b
), it is assumed that a route connecting the main lane through the junction A to the branch lane is selected as a recommended route, and that the route guidance is made so that the vehicle may run on the route. Here, as described above, in the case where the vehicle changes the lane before the junction A and goes straight to pass the junction A, leading to the correction of the current position to the candidate position B on the main lane by the map matching, it results in that the vehicle deviates from the recommended route during the route guidance, thus the auto-rerouting is executed. Specifically, the corrected current position B is set as starting point, a recommended route to the destination is searched again, and the re-searched route is newly set as a recommended route. Thus, the route guidance is performed.
Moreover, as described above, in the case where the map matching is performed when the vehicle reaches the point D on the branch lane, and as a result, the current position is corrected to the candidate position F on the branch lane, it results in that the vehicle deviates from the recommended route searched again by the previous auto-rerouting. Accordingly, the auto-rerouting is executed again. Specifically, the corrected current position F is set as a starting point, a recommended route to the destination is searched again, and the re-sea
Cuchlinski Jr. William A.
Hernandez Olga
Xanavi Informatics Corporation
LandOfFree
Route guidance device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Route guidance device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Route guidance device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3000403