System and method for determining position using doppler velocities
First Claim
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1. A method for determining a position of a GPS receiver capable of receiving navigation messages from a plurality of satellites comprising the steps of:
- receiving navigation messages from a plurality of satellites;
measuring Doppler velocities for the plurality of satellites from the received navigation messages at a given time;
calculating Doppler velocities for an estimated position of the receiver corresponding to the plurality of satellites from ephemeris data at the given time;
comparing calculated Doppler velocities with measured Doppler velocities for the plurality of satellites;
finding a corrected estimated position of the receiver using the compared Doppler velocities; and
iterating the position estimate by using the corrected estimated position to calculate new Doppler velocities for the plurality of satellites and comparing the calculated new Doppler velocities to the measured Doppler velocities.
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Abstract
This disclosure is directed to systems and methods for providing GPS positioning determinations from a single set of Doppler measurements from a plurality of satellites in conjunction with satellite ephemeris data and a rough GPS time estimate. Measured Doppler velocities are compared with Doppler velocities calculated from ephemeris data and used to estimate the receiver position.
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Citations
18 Claims
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1. A method for determining a position of a GPS receiver capable of receiving navigation messages from a plurality of satellites comprising the steps of:
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receiving navigation messages from a plurality of satellites; measuring Doppler velocities for the plurality of satellites from the received navigation messages at a given time; calculating Doppler velocities for an estimated position of the receiver corresponding to the plurality of satellites from ephemeris data at the given time; comparing calculated Doppler velocities with measured Doppler velocities for the plurality of satellites; finding a corrected estimated position of the receiver using the compared Doppler velocities; and iterating the position estimate by using the corrected estimated position to calculate new Doppler velocities for the plurality of satellites and comparing the calculated new Doppler velocities to the measured Doppler velocities. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A GPS receiver configured to:
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receive navigation messages from a plurality of satellites; measure Doppler velocities for the plurality of satellites at a given time from the received navigation messages; calculate Doppler velocities for an estimated position of the receiver corresponding to the plurality of satellites from ephemeris data at the given time; compare calculated Doppler velocities with measured Doppler velocities for the plurality of satellites; find a corrected estimated position of the receiver using the compared Doppler velocities; and iterate the position estimate by using the corrected estimated position to calculate new Doppler velocities for the plurality of satellites and comparing the calculated new Doppler velocities to the measured Doppler velocities. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification