Recognition of and method and apparatus for GPS antenna lever arm compensation in integrated GPS/dead reckoning navigation systems
First Claim
1. A method for improving the heading of a global positioning satellite (GPS) receiver installed on a movable vehicle, the GPS receiver including a GPS antenna for receiving GPS signals, the method comprising the steps of:
- recognizing that when the movable vehicle is turning the GPS antenna has a velocity component not aligned with a velocity of the movable vehicle when the GPS antenna is offset relative to a center of rotation of the vehicle;
recognizing that said velocity component of the GPS antenna causes error in heading of the GPS receiver; and
compensating the heading of the GPS receiver based upon the recognition of said velocity component of the GPS antenna using an external source of heading.
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Accused Products
Abstract
This invention reduces the error growth associated with vehicle Dead Reckoning (DR) systems utilizing heading rate sensors (15) by compensating for the lever arm or offset between the Global Positioning System (GPS) antenna (11) and the center of rotation of the vehicle. When turning at moderate speeds, the error induced in the GPS heading by this lever arm can be the dominant error effect. Accordingly, the present invention recognizes this source of error and further describes a method and apparatus for estimating and compensating for the error effect of this lever arm.
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Citations
22 Claims
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1. A method for improving the heading of a global positioning satellite (GPS) receiver installed on a movable vehicle, the GPS receiver including a GPS antenna for receiving GPS signals, the method comprising the steps of:
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recognizing that when the movable vehicle is turning the GPS antenna has a velocity component not aligned with a velocity of the movable vehicle when the GPS antenna is offset relative to a center of rotation of the vehicle; recognizing that said velocity component of the GPS antenna causes error in heading of the GPS receiver; and compensating the heading of the GPS receiver based upon the recognition of said velocity component of the GPS antenna using an external source of heading. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for compensating for heading error effects in a global positioning satellite (GPS) receiver residing on a movable vehicle caused by a GPS antenna being offset relative to a center of rotation of said movable vehicle, said apparatus comprising:
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an external source of heading for sensing heading changes of said movable vehicle; means for determining a heading residual between a GPS heading derived from said GPS receiver and a heading based on said external source of heading; means for determining a lever arm distance that said GPS antenna is offset relative to the center of rotation of said movable vehicle using said heading residual; and means for compensating said GPS heading from error induced by said GPS antenna being offset relative to the center of rotation of said movable vehicle using said determined lever arm distance. - View Dependent Claims (12, 13, 14)
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15. Apparatus for compensating for heading error effects in a global positioning satellite (GPS) receiver installed on a movable vehicle, said heading error effects caused by a GPS antenna being offset relative to a center of rotation of the movable vehicle, the apparatus comprising:
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an external source of heading for sensing heading changes of said movable vehicle; means for determining a heading residual between a GPS heading derived from said GPS receiver and a heading based on said external source of heading; means for determining a lever arm distance that said GPS antenna is offset relative to the center of rotation of said movable vehicle; and means for compensating GPS heading based upon said determined lever arm distance. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification