Method and apparatus for forming a dynamic model to locate position of a satellite receiver
View Patent ↗Method and apparatus for locating position of a satellite signal receiver is described. In one example, pseudoranges are obtained that estimate the range of a satellite signal receiver to a plurality of satellites. An absolute time and a position are computed using the pseudoranges at a first time. The absolute time is then used to compute another position at a subsequent time. In another example, a plurality of states associated with a satellite signal receiver are estimated, where the plurality of states includes a time tag error state. A dynamic model is then formed relating the plurality of states, the dynamic model operative to compute position of the satellite signal receiver.
1. A method, comprising:
estimating a plurality of states associated with a satellite signal receiver, the plurality of states including a time tag error state, the time tag error state relating a local time associated with said satellite signal receiver and an absolute time associated with signals from a plurality of satellites; and
forming a dynamic model relating the plurality of states, the dynamic model operative to compute position of the satellite signal receiver.
2. The method of claim 1 , wherein the plurality of states further include a state related to a common mode error and at least one state related to the position of the satellite signal receiver.
3. The method of claim 1 , further comprising:
obtaining pseudoranges that estimate the range of the satellite signal receiver to the plurality of satellites;
updating the plurality of states within the dynamic model using the pseudoranges; and
computing a position of the satellite signal receiver using the dynamic model.
4. The method of claim 1 , wherein the dynamic model is formed within a sequential estimator.
5. The method of claim 1 , further comprising;
obtaining time-of-week information;
estimating a known value for the time tag error state within the dynamic model using the time-of-week information.
6. The method of claim 5 , further comprising:
decoding the time-of-week information from ephemeris data transmitted by the plurality of satellites.
7. The method of claim 1 , further comprising:
obtaining time-of-week information;
removing the time tag error state from the dynamic model in response to the time-of-week information.
8. The method of claim 7 , further comprising:
decoding the time-of-week information from ephemeris data transmitted by the plurality of satellites.
9. A mobile device, comprising:
a satellite signal receiver for providing pseudoranges that estimate the range of the mobile device to a plurality of satellites; and
a sequential estimator having a plurality of states associated with the satellite signal receiver, the plurality of states including a time tag error state, the time tag error state relating a local time associated with said satellite signal receiver and an absolute time associate with signals from the plurality of satellites.
10. The mobile device of claim 9 , wherein the sequential estimator is a Kalman filter.