Method and apparatus for improving the accuracy of position estimates in a satellite based navigation system
First Claim
1. An apparatus for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a satellite-based navigation system having a plurality of navigation satellites, the apparatus comprising:
- first means mounted on the vehicle for receiving the navigation signals from the plurality of satellites and for computing, from the navigation signals, a first pseudorange for each of the plurality of satellites, each said first pseudorange representing the distance between said first means and a corresponding one of the plurality of satellites;
second means mounted on the vehicle for receiving the navigation signals from the plurality of satellites and for computing a second pseudorange for each of the plurality of satellites from the navigation signals, each said second pseudorange representing the distance between said second means and a corresponding one of the plurality of satellites;
third means for receiving said first and second pseudoranges and for computing, for each one of the plurality of satellites, an optimal pseudorange;
fourth means for computing a satellite position for each of the plurality of satellites from the navigation signals received by said first means; and
fifth means for computing the position of the vehicle from said satellite positions and said optimal pseudoranges.
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Abstract
An apparatus and method are disclosed for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a satellite-based navigation system. Precise position estimates are achieved by reducing effective receiver noise. A plurality of receiver means each compute a pseudorange for each satellite. A signal optimizer then uses the pseudoranges from each receiver means to compute an optimal pseudorange for each satellite. A processor means computes a vehicle position from the optimal pseudoranges.
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Citations
7 Claims
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1. An apparatus for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a satellite-based navigation system having a plurality of navigation satellites, the apparatus comprising:
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first means mounted on the vehicle for receiving the navigation signals from the plurality of satellites and for computing, from the navigation signals, a first pseudorange for each of the plurality of satellites, each said first pseudorange representing the distance between said first means and a corresponding one of the plurality of satellites; second means mounted on the vehicle for receiving the navigation signals from the plurality of satellites and for computing a second pseudorange for each of the plurality of satellites from the navigation signals, each said second pseudorange representing the distance between said second means and a corresponding one of the plurality of satellites; third means for receiving said first and second pseudoranges and for computing, for each one of the plurality of satellites, an optimal pseudorange; fourth means for computing a satellite position for each of the plurality of satellites from the navigation signals received by said first means; and fifth means for computing the position of the vehicle from said satellite positions and said optimal pseudoranges. - View Dependent Claims (2)
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3. An apparatus for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a Global Positioning System which includes a plurality of satellites orbiting the Earth, the apparatus comprising:
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first means mounted on the vehicle for receiving the, navigation signals from the plurality of satellites; second means mounted on the vehicle for receiving the navigation signals from the plurality of satellites; third means, electrically connected to said first and second means, for computing a satellite position for each satellite based on the navigation signals received by said first and second means, a first pseudorange from the navigation signals received by said first means, and a second pseudorange based on the navigation signals received by said second means; fourth means for receiving said first and second pseudoranges and for computing an optimal pseudorange for each satellite; and fifth means for computing the position of the vehicle from said satellite positions and said optimal pseudoranges. - View Dependent Claims (4)
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5. A method for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a satellite-based navigation system having a plurality of satellites, the method comprising the steps of:
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(a) receiving the navigation signals from each of the plurality of satellites at a plurality of antennas mounted on the vehicle; (b) computing from the navigation signals, for each antenna, a pseudorange to each satellite; (c) computing an optimal pseudorange for each satellite by averaging said pseudoranges across said plurality of antennas; (d) computing a satellite position for each of the plurality of satellites from the navigation signals; and (e) determining the position of the vehicle from said satellite positions and said optimal pseudoranges. - View Dependent Claims (6, 7)
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Specification