Method and apparatus for computing position using instantaneous doppler measurements from satellites
Method and apparatus for computing position using instantaneous Doppler measurements from satellites is described. In one example, instantaneous Doppler measurements are measured for a plurality of satellite signals relative to a satellite signal receiver. The instantaneous Doppler measurements are transmitted to a server. Position of the satellite signal receiver is computed at the server using the instantaneous Doppler measurements. In another example, at least one fractional pseudorange is measured between the satellite signal receiver and a respective at least one satellite. At least one instantaneous Doppler measurement is measured for a respective at least one satellite signal relative to the satellite signal receiver. The at least one pseudorange and the at least one instantaneous Doppler measurement are sent to a server. Position of the satellite signal receiver is computed at the server using the at least one pseudorange and the at least one instantaneous Doppler measurement.
1. A method of locating position of a satellite signal receiver, comprising:
measuring at least one fractional pseudorange between the satellite signal receiver and a respective at least one satellite;
measuring at least one instantaneous Doppler measurement for a respective at least one satellite signal relative to the satellite signal receiver;
transmitting the at least one pseudorange and the at least one instantaneous Doppler measurement to a server; and
computing a position of the satellite signal receiver at the server using the at least one pseudorange and the at least one instantaneous Doppler measurement, wherein computing comprises:
computing an initial position of the satellite signal receiver using the at least one instantaneous Doppler measurement;
computing an integer millisecond portion of the at least one fractional pseudorange using the initial position to form at least one full pseudorange; forming pseudorange residuals using the at least one full pseudorange and the initial position; and
computing an update of the initial position.
2. The method of claim 1 , wherein the position is a two-dimensional position comprising x and y coordinates in a horizontal plane.
3. The method of claim 1 , wherein the computing step comprises:
estimating an initial position of the satellite signal receiver;
forming Doppler residuals using the initial position and the at least one instantaneous Doppler measurement;
forming pseudorange residuals using the initial position and the at least one fractional pseudorange;
relating the Doppler residuals and the pseudorange residuals to a change in the initial position; and
computing an update of the initial position.
4. The method of claim 3 , wherein the estimating step comprises: obtaining an approximate position of the satellite signal receiver from a wireless communication network.
5. The method of claim 3 , wherein the initial position is an arbitrary location.
6. The method of claim 3 , wherein the initial position is a center of a country or a continent in which the satellite signal receiver is operating.
7. The method of claim 1 , further comprising: computing a frequency error associated with an oscillator of the satellite signal receiver using the at least one instantaneous Doppler measurement and the at least one fractional pseudorange.
8. The method of claim 1 , further comprising: computing a time error associated with a clock of the satellite signal receiver using the at least one instantaneous Doppler measurement and the at least one fractional pseudorange.
9. The method of claim 1 , wherein the instantaneous Doppler measurements are measured over a time interval that is less than one second.
10. The method of claim 9 , wherein measuring at least one instantaneous Doppler measurement for a respective at least one satellite signal relative to the satellite signal receiver further comprises measuring at least one instantaneous for a single satellite signal relative to the satellite signal receiver by measuring the Doppler measurement for only the single satellite signal relative to the satellite signal receiver.
11. A system for locating position, comprising:
a remote receiver having a satellite signal receiver, a microcontroller, and a wireless transceiver; and a server in wireless communication with the remote receiver;
where the satellite signal receiver receives satellite signals; where the microcontroller determines at least one fractional pseudorange between the satellite signal receiver and at least one satellite and determines at least one instantaneous Doppler measurement for at least one satellite signal of the satellite signals relative to the satellite signal receiver; and
where the wireless transceiver transmits the at least one fraction pseudorange and the at least one instantaneous Doppler measurement to the server for computing a position of the remote receiver; and
wherein the instantaneous Doppler measurements are measured over a time interval that is less than one second; and
wherein measuring at least one instantaneous Doppler measurement for a respective at least one satellite signal relative to the satellite signal receiver further comprises measuring at least one instantaneous for a single satellite signal relative to the satellite signal receiver by measuring the Doppler measurement for only the single satellite signal relative to the satellite signal receiver.
12. The system of claim 11 , wherein the server is configured to estimate an initial position of the satellite signal receiver, form Doppler residuals using the initial position and the at least one instantaneous Doppler measurement, form pseudorange residuals using the initial position and the at least one fractional pseudorange, relate the Doppler residuals and the pseudorange residuals to a change in the initial position, and compute an update of the initial position.
13. A method of locating position of a satellite signal receiver, comprising:
measuring at least one fractional pseudorange between the satellite signal receiver and a respective at least one satellite;
measuring at least one instantaneous Doppler measurement for a respective at least one satellite signal relative to the satellite signal receiver;
transmitting the at least one pseudorange and the at least one instantaneous Doppler measurement to a server; and
computing a position of the satellite signal receiver at the server using the at least one pseudorange and the at least one instantaneous Doppler measurement; and
wherein the instantaneous Doppler measurements are measured over a time interval that is less than one second; and
wherein measuring at least one instantaneous Doppler measurement for a respective at least one satellite signal relative to the satellite signal receiver comprises measuring at least one instantaneous for a single satellite signal relative to the satellite signal receiver by measuring the Doppler measurement for only the single satellite signal relative to the satellite signal receiver.
14. The method of claim 13 , wherein the position is a two-dimensional position comprising x and y coordinates in a horizontal plane.
15. The method of claim 13 , wherein the computing step comprises: estimating an initial position of the satellite signal receiver:
forming Doppler residuals using the initial position and the at least one instantaneous Doppler measurement;
forming pseudorange residuals using the initial position and the at least one fractional pseudorange;
relating the Doppler residuals and the pseudorange residuals to a change in the initial position; and
computing an update of the initial position.
16. The method of claim 15 , wherein the estimating step comprises: obtaining an approximate position of the satellite signal receiver from a wireless communication network.
17. The method of claim 15 , wherein the initial position is an arbitrary location.
18. The method of claim 15 , wherein the initial position is a center of a country or a continent in which the satellite signal receiver is operating.
19. The method of claim 13 , further comprising: computing a frequency error associated with an oscillator of the satellite signal receiver using the at least one instantaneous Doppler measurement and the at least one fractional pseudorange.
20. The method of claim 13 , further comprising: computing a time error associated with a clock of the satellite signal receiver using the at least one instantaneous Doppler measurement and the at least one fractional pseudorange.