Method and apparatus for position determination with extended SPS orbit information
First Claim
1. A processor-implemented method on a mobile station, comprising:
- receiving, by the mobile station, coarse orbit data, wherein the coarse orbit data comprises a coarse estimate of positions and clock timing of a first satellite;
receiving, by the mobile station over a communication network coupled to a location assistance server, correction information for the first satellite, the correction information for the first satellite being generated by the location assistance server based on a difference between the same coarse orbit data received by the mobile station and precise orbit data, and further based on a first coordinate system defined as a function of an instantaneous position of the first satellite, wherein the precise orbit data comprises a precise estimate of the positions and clock timing of the first satellite;
converting, by the mobile station, the received correction information for the first satellite from the first coordinate system to a second coordinate system;
computing, by a processor of the mobile station, the positions and clock timing of the first satellite based on the received coarse orbit data and the correction information for the first satellite;
receiving, by the mobile station, real-time orbit data of a second satellite, wherein the real-time orbit data is sent to the mobile station through satellite positioning system (SPS) signals broadcast from the second satellite and comprises a precise representation of positions and clock timing of the second satellite;
computing, by the processor of the mobile station, the positions and clock timing of the second satellite based on additional coarse orbit data and correction information, the additional coarse orbit data and correction information received by the mobile station for the second satellite;
determining, by the processor of the mobile station, a first estimated location for the mobile station based on the real-time orbit data of the second satellite and the computed positions and clock timing of the first satellite, wherein the first estimated location is an estimated position of the mobile station;
switching from the real-time orbit data of the second satellite to the computed positions and clock timing of the second satellite in response to at least one of;
expiration of a period of validity of the real-time orbit data of the second satellite, or a lack of line of sight to the second satellite, or a lack of signal reception from the second satellite; and
after switching to the computed positions and clock timing of the second satellite, using the computed positions and clock timing of the second satellite to determine a second estimated location for the mobile station, wherein the second estimated location is an estimated position of the mobile station.
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Abstract
A method and system for assisting mobile stations to locate a satellite use an efficient messaging format. A server computes a correction between coarse orbit data of a satellite and precise orbit data of the satellite. A coordinate system is chosen such that variation of the correction is substantially smooth over time. The server further approximates the correction with mathematical functions to reduce the number of bits necessary for transmission to a mobile station. The mobile station, upon receiving the coefficients, evaluates the mathematical functions using the coefficients and a time of applicability (e.g., the current time), converts the evaluated result to a standard coordinate system, and applies the conversion result to the coarse orbit data to obtain the precise orbit data.
81 Citations
25 Claims
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1. A processor-implemented method on a mobile station, comprising:
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receiving, by the mobile station, coarse orbit data, wherein the coarse orbit data comprises a coarse estimate of positions and clock timing of a first satellite; receiving, by the mobile station over a communication network coupled to a location assistance server, correction information for the first satellite, the correction information for the first satellite being generated by the location assistance server based on a difference between the same coarse orbit data received by the mobile station and precise orbit data, and further based on a first coordinate system defined as a function of an instantaneous position of the first satellite, wherein the precise orbit data comprises a precise estimate of the positions and clock timing of the first satellite; converting, by the mobile station, the received correction information for the first satellite from the first coordinate system to a second coordinate system; computing, by a processor of the mobile station, the positions and clock timing of the first satellite based on the received coarse orbit data and the correction information for the first satellite; receiving, by the mobile station, real-time orbit data of a second satellite, wherein the real-time orbit data is sent to the mobile station through satellite positioning system (SPS) signals broadcast from the second satellite and comprises a precise representation of positions and clock timing of the second satellite; computing, by the processor of the mobile station, the positions and clock timing of the second satellite based on additional coarse orbit data and correction information, the additional coarse orbit data and correction information received by the mobile station for the second satellite; determining, by the processor of the mobile station, a first estimated location for the mobile station based on the real-time orbit data of the second satellite and the computed positions and clock timing of the first satellite, wherein the first estimated location is an estimated position of the mobile station; switching from the real-time orbit data of the second satellite to the computed positions and clock timing of the second satellite in response to at least one of;
expiration of a period of validity of the real-time orbit data of the second satellite, or a lack of line of sight to the second satellite, or a lack of signal reception from the second satellite; andafter switching to the computed positions and clock timing of the second satellite, using the computed positions and clock timing of the second satellite to determine a second estimated location for the mobile station, wherein the second estimated location is an estimated position of the mobile station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 23)
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9. A mobile station, comprising:
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a receiver, the receiver configured to; receive coarse orbit data, wherein the coarse orbit data comprises a coarse estimate of positions and clock timing of a first satellite; receive, over a communication network coupled to a location assistance server, correction information for the first satellite, the correction information for the first satellite being generated by the location assistance server based on a difference between the same coarse orbit data received by the mobile station and precise orbit data, and further based on a first coordinate system defined as a function of an instantaneous position of the first satellite, wherein the precise orbit data comprises a precise estimate of the positions and clock timing of the first satellite; convert the received correction information for the first satellite from the first coordinate system to a second coordinate system; and receive real time orbit data of a second satellite, wherein the real-time orbit data is sent to the mobile station through satellite positioning system (SPS) signals broadcast from the second satellite and comprises a precise representation of positions and clock timing of the second satellite; and a processor coupled to the receiver, wherein the processor is configured to; compute the positions and clock timing of the first satellite based on the received coarse orbit data and the correction information for the first satellite; compute the positions and clock timing of the second satellite based on additional coarse orbit data and correction information, the additional coarse orbit data and correction information received by the mobile station for the second satellite; determine a first estimated location for the mobile station based on the real-time orbit data of the second satellite and the computed positions and clock timing of the first satellite, wherein the first estimated location is an estimated position of the mobile station; switch from the real-time orbit data of the second satellite to the computed positions and clock timing of the second satellite in response to at least one of;
expiration of a period of validity of the real-time orbit data of the second satellite, or a lack of line of sight to the second satellite, or a lack of signal reception from the second satellite; andafter switching to the computed positions and clock timing of the second satellite, use the computed positions and clock timing of the second satellite to determine a second estimated location for the mobile station, wherein the second estimated location is an estimated position of the mobile station. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 24)
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17. A non-transitory computer-readable medium comprising instructions, which when executed by a processor of a mobile station, cause the processor to:
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receive coarse orbit data, wherein the coarse orbit data comprises a coarse estimate of positions and clock timing of a first satellite; receive, over a communication network coupled to a location assistance server, correction information for the first satellite, the correction information for the first satellite being generated by the location assistance server based on a difference between the same coarse orbit data received by the mobile station and precise orbit data, and further based on a first coordinate system defined as a function of an instantaneous position of the first satellite, wherein the precise orbit data comprises a precise estimate of the positions and clock timing of the first satellite; convert the received correction information for the first satellite from the first coordinate system to a second coordinate system; compute the positions and clock timing of the first satellite based on the received coarse orbit data and the correction information for the first satellite; receive real-time orbit data of a second satellite, wherein the real-time orbit data is sent to the mobile station through satellite positioning system (SPS) signals broadcast from the second satellite and comprises a precise representation of positions and clock timing of the second satellite; compute the positions and clock timing of the second satellite based on additional coarse orbit data and correction information, the additional coarse orbit data and correction information received by the mobile station for the second satellite; determine a first estimated location for the mobile station based on the real-time orbit data of the second satellite and the computed positions and clock timing of the first satellite, wherein the first estimated location is an estimated position of the mobile station; switch from the real-time orbit data of the second satellite to the computed positions and clock timing of the second satellite in response to at least one of;
expiration of a period of validity of the real-time orbit data of the second satellite, or a lack of line of sight to the second satellite, or a lack of signal reception from the second satellite; andafter switching to the computed positions and clock timing of the second satellite, use the computed positions and clock timing of the second satellite to determine a second estimated location for the mobile station, wherein the second estimated location is an estimated position of the mobile station. - View Dependent Claims (18, 19, 20, 21, 22, 25)
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Specification