Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2002-05-06
2003-07-22
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C340S988000
Reexamination Certificate
active
06597985
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field Pertinent to the Invention
The present invention relates to a technical field of a positioning apparatus and a navigation apparatus, and a positioning method and a navigation method. More particularly, the present invention relates to a positioning apparatus which measures a current position of a vehicle by the use of the position measuring information transmitted from GPS (Global Positioning System) satellite which has been launched in cosmic space and supports movement of the vehicle and a positioning method, and a navigation apparatus including the current positioning apparatus and a navigation method including the current positioning method.
2. Related Background Art
Recently, it has been widely generalized to specify a current position of a movable body such as a vehicle or the like by the use of the position measuring information transmitted from a positioning satellite such as the above described GPS satellite to be used for specifying a position of the movable body on the earth.
According to the above described conventional positioning processing by the use of the position measuring information, specifically, a current position at the present time has been calculated by using both of an estimated position at the present time which is obtained from the current position calculated by the former positioning processing on the base of a predetermined estimation method and a measured position at the present time which is calculated only by using the position measuring information received at the present time. Then, finally, this calculated current position is displayed as a current position of the vehicle, which is calculated by the use of the above described GPS satellite, for example, on a display in the vehicle.
On the one hand, as the first related background art, the reception of the position measuring information to be transmitted from the above described positioning satellite is interrupted, for example, while the vehicle is moving in a tunnel or the like, so that it becomes impossible to calculate the above described measured position.
Therefore, according to the above described conventional positioning processing, if the position measuring information has been not obtained during a period which is longer than a predetermined threshold value (more specifically, for example, three seconds), assuming that accuracy of the above described estimated position during a period in which this position measuring information has been not obtained, a reset process has been performed in such a manner that an estimated position to be calculated on the basis of a current position before the interruption is ignored and the above described measured position to be obtained after the reception of the position measuring information restarts is defined as a current position of the movable body at the present time. Further, according to the conventional positioning processing, the above described threshold value comprises a predetermined value as a fixed value.
On the other hand, as the second related background art, when a position includes a plan position and an altitude of the movable body, according to the above described conventional positioning processing, in the case where degrees of accuracy of an estimated position and a positioning position are lowered, the reset processing has been performed in such a manner that the estimated position and the positioning position, which were calculated at precedence timing, are ignored and the estimated position just after obtained is defined as a current position of the movable body in that time.
Alternatively, it is assumed that the degrees of the accuracy of the above estimated position and the positioning position indicating timing, at which this reset processing starts, are detected to be lowered specifically when a difference between the altitude information calculated as the above estimated position (namely, the altitude information of a vehicle calculated only on the basis of the position measuring information) and the altitude information included in the above estimated information (namely, the estimated altitude information calculated as the estimated position) becomes not less than a predetermined threshold value. The present threshold value is defined as a higher value in some measure in association with an error to be principally included in the position measuring information.
However, according to the conventional positioning processing having the above described constitution of the first related background art, since the threshold value comprises a predetermined value as a fixed value, the following scopes for improvement have been occur.
In other words, at first, under the condition that the position measuring information having a low degree of accuracy is only obtained after the time shown by the threshold value has been passed, the positioning position having an extremely low degree of accuracy is identified as a current position. Accordingly, this involves a scope for improvement such that the accuracy of the current position also becomes extremely low.
Additionally, secondly, under the condition that the new position measuring information having a high degree of accuracy is obtained before the time shown by the threshold value has been passed, the above described positioning position is calculated in such a manner that the estimated position when the time shown by the threshold value has been passed is added to the positioning position on the basis of this position measuring information having a high degree of accuracy. Accordingly, this involves a scope for improvement such that, despite the positioning position having a high degree of accuracy has been obtained, only the current position having a degree of accuracy which is lower than that of the positioning position is calculated.
On the other hand, according to the conventional positioning processing having the above described constitution of the second related background art, the above threshold value comprises a fixed value and a high value in some measure, so that this involves a scope for improvement such that there is a case that the reset processing does not start when the need arises.
More specifically, for example, if the degrees of the accuracy of the estimated position and the positioning position are decreased, the reset processing on the basis of the difference in the altitude information does not start even when the positional error is obviously included in the current position of the vehicle which is displayed on the display. As a result, there is a case that the current positional error becomes larger.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made taking the foregoing scopes for improvement into consideration, an object of which is to provide a positioning apparatus capable of calculating a current position at a higher degree of accuracy compared to a conventional case by the positioning position and the estimated position and a positioning method, and a navigation apparatus including the current positioning apparatus and a navigation method including the current positioning method.
The above object of the present invention can be achieved by a positioning apparatus. In one aspect of the present invention, there is provided a positioning apparatus which measures a current position of a movable body on the basis of a position information indicating a position of said movable body which was measured in the past by the use of a position measuring information transmitted from a positioning satellite. The positioning apparatus is provided with: a detecting device which detects a receiving condition of said position measuring information; a measuring device which ignores said position information which was obtained in the past when a precision of said position measuring information is decided to be deteriorated on the basis of a threshold value and measures said current position of said movable body by the use of said position measuring information which is received at the present time; and a contro
Cuchlinski Jr. William A.
Hernandez Olga
Pioneer Corporation
Sughrue & Mion, PLLC
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