Method and apparatus for processing of satellite signals without time of day information
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 of locating position of a satellite from a satellite signal receiver, the method comprising:
receiving a first plurality of data from the satellite;
computing an initial satellite position estimate, estimating a position of the satellite at a particular time according to a mathematical model and the first plurality of data;
receiving a second plurality of data from the satellite; and
computing an updated satellite position estimate, estimating the position of the satellite at the same particular time as estimated by the initial satellite position estimate, according to the mathematical model and the second plurality of data.
2. The method of claim 1 , wherein the initial satellite position estimate and the updated satellite position estimate are computed within the satellite signal receiver.
3. The method of claim 1 , wherein the first plurality of data comprises at least one pseudorange that estimates a distance of the satellite signal receiver to the satellite.
4. The method of claim 3 , wherein the mathematical model is used to create an absolute time according to the at least one pseudorange.
5. The method of claim 4 , wherein the initial satellite position estimate is computed according to the absolute time.
6. The method of claim 1 , wherein computing the initial satellite position estimate comprises computing a particular time estimate.
7. The method of claim 6 , wherein computing the updated satellite position estimate comprises updating the initial satellite position estimate and the particular time estimate.
8. The method of claim 1 , wherein the mathematical model is dynamically updated according to the second plurality of data.
9. A system for computing position of a satellite, the system comprising:
a receiver for receiving a first plurality of data from the satellite at a first time and receiving a second plurality of data from the satellite at a second time; and
a processor for using a mathematical model, wherein the processor computes an initial satellite position estimate, estimating a position of the satellite at a particular time according to the mathematical model and the first plurality of data, and wherein the processor computes an updated satellite position estimate, estimating the position of the satellite at the same particular time as estimated by the initial satellite position estimate, according to the mathematical model and the second plurality of data.
10. The system of claim 9 , wherein the processor and the receiver are in a single device.
11. The system of claim 9 , wherein the first plurality of data comprises at least one pseudorange for estimating a distance of the receiver to the satellite.
12. The system of claim 9 , wherein the mathematical model is used to create an absolute time according to the at least one pseudorange.
13. The system of claim 12 , wherein the initial satellite position estimate is computed according to the absolute time.
14. The system of claim 9 , wherein computing the initial satellite position estimate comprises computing a particular time estimate.
15. The system of claim 14 , wherein computing the updated satellite position estimate comprises updating the initial satellite position estimate and the particular time estimate.
16. The system of claim 9 , wherein the mathematical model is dynamically updated according to the second plurality of data.
17. The method of claim 4 , wherein the absolute time is not initially accurately known.
18. The system of claim 12 , wherein the absolute time is not initially accurately known.