Method and apparatus for determining the geographic location of a device
View Patent ↗A method and apparatus for determining the location of a device from signals provided by a plurality of satellites. A device receives a first plurality of signals comprising one signal from each of a first plurality of satellites and determines a first location of the device as a function of the first plurality of signals. The device then determines a second location thereof as a function of a second plurality of signals if the first location is not within a predetermined threshold. The second plurality of signals is a first subset of the first plurality of signals.
1. In a method for determining the location of a device receiving signals from each of a plurality of satellites, the device having determined a first location from the received signals, the improvement comprising the steps of:
(a) comparing a quality of the first location of the device with a predetermined threshold; and
(b) determining additional locations of the device for each different combination of the received signals while leaving out N signal from the received signals if the quality of the first location is not within the predetermined threshold,
wherein N is a positive integer, and wherein the quality is defined by a lowest sum of the squared residuals.
2. The method of claim 1 wherein at least one of the received signals is provided by a cellular network.
3. The method of claim 2 wherein the quality is a function of information provided by the cellular network.
4. The method of claim 1 wherein the satellites are part of a Global Navigation Satellite System (“GNSS”).
5. The method of claim 4 wherein the GNSS is selected from the group consisting of: Global Positioning System (“GPS”), Galileo, GLONASS, and Quasi-Zenith Satellite System (“QZSS”).
6. The method of claim 1 wherein the device is a mobile unit.
7. The method of claim 6 wherein the mobile unit is selected from the group consisting of: cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.
8. A system for determining a location of a device from signals received from a plurality of Global Navigation Satellite System (“GNSS”) satellites comprising:
a receiver for receiving signals from each of a plurality of satellites;
a means for determining a first location of the device as a function of a quality of the received signals; and
a means for determining additional locations of the device as a function of each subset of said received signals while leaving out N signal from the received signals if said quality is not within a predetermined threshold, wherein N is a positive integer,
wherein said quality is a function of a lowest sum of the squared residuals determined from said signals.
9. The system of claim 8 wherein the satellites are part of a Global Navigation Satellite System (“GNSS”).
10. The system of claim 9 wherein the GNSS is selected from the group consisting of: Galileo, GLONASS, and Quasi-Zenith Satellite System (“QZSS”).
11. The system of claim 8 wherein the satellites are Global Positioning System (“GPS”) satellites.
12. The system of claim 8 wherein said quality is a function of ephemeris information transmitted by at least one satellite.
13. The system of claim 8 wherein the device is a mobile unit.
14. The system of claim 13 wherein the mobile unit is selected from the group consisting of: cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.
15. The system of claim 13 wherein the mobile unit receives signals from a cellular network.
16. The system of claim 15 wherein the location of the device is a function of information provided by the cellular network.
17. A method of calculating the position of a device comprising the steps of:
(a) receiving a first plurality of observations from a first plurality of satellites;
(b) determining a first position of the device as a function of a quality of the first plurality of observations;
(c) if the quality of the first plurality of observations fails to meet the predefined threshold then:
(i) determining a second position of the device as defined by a quality of a second plurality of observations, the second plurality being a subset of the first plurality of observations,
(ii) if the quality of the second plurality of observations fails to meet the predefined threshold then repeating step (i) for each subset of the first plurality of observations while leaving out at least one received observation, and
(iii) determining additional positions of the device using incrementally decreasing subsets of observations until a predetermined criteria is achieved.
18. The method of claim 17 wherein the criteria is a cardinality of observations is at least four.
19. The method of claim 17 wherein the criteria is the quality meets the predefined threshold.
20. The method of claim 17 wherein the criteria is the quality of all combinations of satellite observations have failed to meet the predefined threshold.
21. The method of claim 17 wherein the quality is a function of a lowest sum of the squared residuals.
22. The method of claim 17 wherein the device is receiving signals from a cellular network.
23. The method of claim 22 wherein the quality is a function of information provided from the cellular network.
24. The method of claim 17 wherein the satellites are part of a Global Navigation Satellite System (“GNSS”).
25. The method of claim 24 wherein the GNSS is selected from the group consisting of: Global Positioning System (“GPS”), Galileo, GLONASS, and Quasi-Zenith Satellite System (“QZSS”).
26. The method of claim 17 wherein the device is a mobile unit.
27. The method of claim 26 wherein the mobile unit is selected from the group consisting of: cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.