System and method for measuring a position of a moving object with a hybrid navigation apparatus
First Claim
1. A hybrid system for deriving a position of a moving object, comprising:
- (a) first means for receiving an electromagnetic wave from at least one satellite and a Global Positioning System for the measurement of an absolute position of the moving object and for deriving the position of the moving object on the basis of data from the received electromagnetic wave;
(b) second means, having a first sensor for detecting a movement direction of the moving object and a second sensor for detecting a movement speed of the moving object, for calculating a product of the detected movement direction and movement speed of the moving object and integrating the product with respect to time so as to derive a movement distance of the moving object and direction thereof with respect to a reference position and for calculating a sum of(i) the derived movement distance, and(ii) direction and the reference position so as to derive a current position of the moving object;
(c) third means for comparing at least two successively derived positions of the first means with the derived current position of the second means so as to evaluate a reliability of the at least two derived positions of the first means; and
(d) fourth means for setting a latter one of said at least two derived positions of the third means as the reference position when the third means evaluates that the two derived positions of the first means are reliable.
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Accused Products
Abstract
A system and method for measuring a position of a moving object such as a vehicle using a hybrid-type navigation apparatus. In the system and method, at least two measurement results of an electromagnetic wave position measuring apparatus (such as a GPS position measuring apparatus) are evaluated to determine whether they are reliable with respect to the those derived by an integration calculation position measuring apparatus incorporated in the system together with the electromagnetic wave position measuring apparatus on the basis of the corresponding measurement results by means of the integration calculation position measuring apparatus. When they are determined to be highly reliable, a measurement result of the electromagnetic wave position measuring apparatus subsequent to those evaluated is set to a reference position on the basis of which the integration calculation position measuring apparatus measures the position of the moving object. Consequently, a highly reliable measurement of the position of the moving object can always be achieved.
97 Citations
14 Claims
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1. A hybrid system for deriving a position of a moving object, comprising:
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(a) first means for receiving an electromagnetic wave from at least one satellite and a Global Positioning System for the measurement of an absolute position of the moving object and for deriving the position of the moving object on the basis of data from the received electromagnetic wave; (b) second means, having a first sensor for detecting a movement direction of the moving object and a second sensor for detecting a movement speed of the moving object, for calculating a product of the detected movement direction and movement speed of the moving object and integrating the product with respect to time so as to derive a movement distance of the moving object and direction thereof with respect to a reference position and for calculating a sum of (i) the derived movement distance, and (ii) direction and the reference position so as to derive a current position of the moving object; (c) third means for comparing at least two successively derived positions of the first means with the derived current position of the second means so as to evaluate a reliability of the at least two derived positions of the first means; and (d) fourth means for setting a latter one of said at least two derived positions of the third means as the reference position when the third means evaluates that the two derived positions of the first means are reliable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A position determining system for a vehicle, comprising:
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(a) first means for receiving an electromagnetic wave and deriving the position of the vehicle on the basis of the received electromagnetic wave; (b) second means for calculating the position of the vehicle with respect to a reference position on the basis of an integration of a product of a moving direction and speed of the vehicle with respect to time, the reference position being calculated from the position of the vehicle derived by the first means; (c) third means for evaluating the reliability of each derived position of the first means by comparing each calculated position of the second means with the corresponding derived position of said first means and setting, as a reference position in the second means, one of the derived positions subsequent to at least two consecutive derived positions of the first means which are evaluated to be reliable; and (d) fourth means for outputting the derived position of the first means, subsequent to the two derived positions of the first means evaluated as being reliable, as the position data of the vehicle.
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14. A method for deriving a position of a moving object, comprising the steps of:
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(a) deriving the position of the moving object using an electromagnetic wave position measuring apparatus; (b) calculating the position of the moving object using an integration calculating apparatus in which the position of the moving object is derived by the sum of (i) a calculated distance and direction of the moving object, and (ii) a reference position, the calculated distance and direction of the moving object being calculated by integrating a product, over time, of the movement direction and movement speed of the moving object; (c) evaluating a reliability of at least two derived positions of said deriving step on the basis of comparing the calculated positions of the integration calculating apparatus corresponding to positions derived by the electromagnetic wave position measuring apparatus; and (d) setting the derived position of the electromagnetic wave position measuring apparatus subsequent to the derived positions of the electromagnetic wave position measuring apparatus evaluated in the step (c) as a reference position when the derived positions of the electromagnetic wave position measuring apparatus are evaluated as being reliable.
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Specification