| 摘要 |
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. |
| 主权项 |
1. A method by a mobile station of locating a satellite, the method comprising:
receiving, by the mobile station, coarse orbit data of the satellite including a coarse estimate of the satellite's position; generating, by the mobile station, a coarse satellite position of the satellite using at least the coarse estimate of the satellite's position; receiving, by the mobile station, coarse orbit correction data of the satellite calculated using the coarse orbit data and predicted orbit data of the satellite, wherein the calculation of the coarse orbit correction data occurs at an entity geographically distinct from the mobile station, and wherein the predicted orbit data is more accurate than the coarse orbit data; reconstructing, by the mobile station, at least one spatial correction value to the coarse orbit data at least based on the coarse orbit correction data; converting, by the mobile station, the at least one spatial correction value from a satellite-centered coordinate system to an earth-centered, earth-fixed coordinate system; and determining, by the mobile station, a corrected position of the satellite using the coarse satellite position of the satellite and the at least one spatial correction value converted to the earth-centered, earth-fixed coordinate system, wherein the corrected position of the satellite is more accurate than the coarse satellite position. |
