Method and device for using GNSS satellite trajectory extension data in mobile apparatus

1. A method for using GNSS satellite trajectory extension data in a mobile apparatus, said method comprising steps of:

obtaining at least one satellite navigation message for a satellite;

determining a propagating condition according to the obtained satellite navigation message;

estimating a plurality of parameters of a satellite trajectory prediction model according to the propagating condition to establish an estimated satellite trajectory prediction model;

propagating a set of satellite trajectory extension data by using the estimated satellite trajectory prediction model;

computing acquisition assistance data according to the satellite trajectory extension data; and

acquiring signals of the satellite by using the acquisition assistance data.

2. The method of claim 1 , further comprising adjusting the propagating condition of the satellite trajectory prediction model to find an optimized state of the satellite trajectory prediction model.

3. The method of claim 2 , wherein the parameters are adjusted with consideration of at least one of either satellite geometric information or coordinate transformation information.

4. The method of claim 1 , wherein the satellite trajectory prediction model is a compact force model parameterized by perturbation force components, and the parameters relate to the perturbation force components.

5. The method of claim 4 , wherein the satellite trajectory extension data set is divided into a plurality of trajectory segments and is propagated by integrating the trajectory segments one by one.

6. The method of claim 1 , wherein the satellite trajectory prediction model is an adjusted orbit model parameterized by orbital parameters.

7. The method of claim 6 , wherein the orbital parameters include Keplerian orbital elements.

8. The method of claim 7 , wherein the orbital parameters further include a plurality of dynamic parameters for describing addition perturbed accelerations acting on the satellite.

9. The method of claim 1 , wherein the satellite navigation message comprises information selected from a group consisting of broadcasting ephemeris, almanac, satellite position state vectors and satellite velocity state vectors.

10. The method of claim 1 , wherein the satellite navigation message is obtained from an external source other than the mobile apparatus.

11. The method of claim 1 , further comprising:

determining if a valid ephemeris for the satellite is available,

wherein the acquisition assistance data is computed according to the valid ephemeris if the valid ephemeris is available, while is computed according to the satellite trajectory extension data if the valid ephemeris is not available.

12. A device for predicting GNSS satellite trajectory extension data used in a mobile apparatus, said device comprising:

an interface for obtaining at least one satellite navigation message for a satellite; and

a microprocessor for determining a propagating condition according to the satellite navigation message, estimating a plurality of parameters of a satellite trajectory prediction model according to the propagating condition to establish an estimated satellite trajectory predication model, propagating a set of satellite trajectory extension data by using the estimated satellite trajectory prediction model, computing acquisition assistance data according to the satellite trajectory extension data, and acquiring signals of the satellite by using the acquisition assistance data.

13. The device of claim 12 , wherein the microprocessor further adjusts the propagating condition of the satellite trajectory prediction model to find an optimized state of the satellite trajectory prediction model.

14. The device of claim 13 , wherein the parameters are adjusted with consideration of at least one of either satellite geometric information or coordinate transformation information.

15. The device of claim 12 , wherein the satellite trajectory prediction model is a compact force model parameterized by perturbation force components, and the parameters relate to the perturbation force components.

16. The device of claim 15 , wherein the satellite trajectory extension data set is divided into a plurality of trajectory segments and is propagated by integrating the trajectory segments one by one.

17. The device of claim 12 , wherein the satellite trajectory prediction model is an adjusted orbit model parameterized by orbital parameters.

18. The device of claim 17 , wherein the orbital parameters include Keplerian orbital elements.

19. The device of claim 18 , wherein the orbital parameters further include a plurality of dynamic parameters for describing additional perturbed accelerations acting on the satellite.

20. The device of claim 12 , wherein the satellite navigation message comprises information selected from a group consisting of broadcasting ephemeris, almanac, satellite position state vectors and satellite velocity state vectors.

21. The device of claim 12 , wherein the satellite navigation message is obtained from an external source other than the mobile apparatus.

22. The device of claim 12 , wherein the microprocessor further determines if a valid ephemeris for the satellite is available, the microprocessor computes the acquisition assistance data according to the valid ephemeris if the valid ephemeris is available, while computes the acquisition assistance data according to the satellite trajectory extension data if the valid ephemeris is not available.