System and method for position calculation of a mobile device

Abstract

A system and method for determining a location of a device. Plural signals from a first plurality of satellites may be received a the device where an estimated location of the device is determined as a function of frequency information from the signals. A location of the device may then be determined as a function of the estimated location and/or as a function of phase information from the signals. A second plurality of satellites may also be determined as a function of any one of the determined locations. In such embodiments, assistance data may be transmitted to the device that includes information from the second plurality of satellites. Another location of the device may then be determined from this information.

1 . A method for determining a location of a device, the method comprising:
 (a) receiving at said device plural signals from a first plurality of satellites;   (b) determining a first estimated location of said device as a function of frequency information from said signals;   (c) determining a second plurality of satellites as a function of said first estimated location;   (d) transmitting assistance data to said device, said assistance data including information from said second plurality of satellites; and   (e) determining a second estimated location of said device from said information from said second plurality of satellites.   
     
     
         2 . The method of  claim 1  further comprising the step of determining a third estimated location of said device as a function of phase information from said signals. 
     
     
         3 . The method of  claim 1  wherein said first plurality of satellites is at least four. 
     
     
         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, Global Navigation Satellite System (“GLONASS”), and Quasi-Zenith Satellite System (“QZSS”). 
     
     
         6 . The method of  claim 1  wherein the device 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. 
     
     
         7 . The method of  claim 1  wherein said first estimated location is determined as a function of coordinates for origin in an Earth-Centered Earth-fixed (“ECEF”) coordinate system. 
     
     
         8 . The method of  claim 1  wherein said first and second plurality of satellites are mutually exclusive. 
     
     
         9 . The method of  claim 1  wherein said frequency information includes Doppler shift information. 
     
     
         10 . The method of  claim 2  wherein said phase information includes coarse acquisition (“C/A”) code phase information. 
     
     
         11 . A system for determining the location of a device from signals received from a plurality of Global Navigation Satellite System (“GNSS”) satellites comprising:
 (a) a receiver for receiving plural signals from a first plurality of satellites;   (b) circuitry for determining a first estimated location of said device as a function of frequency information from said signals;   (c) circuitry for determining a second plurality of satellites as a function of said first estimated location;   (d) a transmitter for transmitting assistance data to said device, said assistance data including information from said second plurality of satellites; and   (e) circuitry for determining a second estimated location of said device from said information from said second plurality of satellites.   
     
     
         12 . The system of  claim 11  further comprising circuitry for determining a third estimated location of said device as a function of phase information from said signals. 
     
     
         13 . The system of  claim 11  wherein said first plurality of satellites is at least four. 
     
     
         14 . The system of  claim 11  wherein the GNSS is selected from the group consisting of: Global Positioning System (“GPS”), Galileo, Global Navigation Satellite System (“GLONASS”), and Quasi-Zenith Satellite System (“QZSS”). 
     
     
         15 . The system of  claim 11  wherein the device 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. 
     
     
         16 . The system of  claim 11  wherein said first estimated location is a function of coordinates for origin in an Earth-Centered Earth-fixed (“ECEF”) coordinate system. 
     
     
         17 . The system of  claim 11  wherein said first and second plurality of satellites are mutually exclusive. 
     
     
         18 . The system of  claim 11  wherein said frequency information includes Doppler shift information. 
     
     
         19 . The system of  claim 12  wherein said phase information includes coarse acquisition (“C/A”) code phase information. 
     
     
         20 . A method for determining a location of a device, the method comprising:
 (a) receiving at said device plural signals from a first plurality of satellites;   (b) determining a first estimated location of said device as a function of frequency information from said signals;   (c) determining a second estimated location of said device as a function of said first estimated location and as a function of phase information from said signals;   (d) determining a second plurality of satellites as a function of said first or second estimated location;   (e) transmitting assistance data to said device, said assistance data including information from said second plurality of satellites; and   (f) determining a third estimated location of said device from said information from said second plurality of satellites.   
     
     
         21 . The method of  claim 20  wherein said first plurality of satellites is at least four. 
     
     
         22 . The method of  claim 20  wherein the satellites are part of a Global Navigation Satellite System (“GNSS”). 
     
     
         23 . The method of  claim 22  wherein the GNSS is selected from the group consisting of: Global Positioning System (“GPS”), Galileo, Global Navigation Satellite System (“GLONASS”), and Quasi-Zenith Satellite System (“QZSS”). 
     
     
         24 . The method of  claim 20  wherein the device 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. 
     
     
         25 . The method of  claim 20  wherein said first estimated location is determined as a function of coordinates for origin in an Earth-Centered Earth-fixed (“ECEF”) coordinate system. 
     
     
         26 . The method of  claim 20  wherein said first and second plurality of satellites are mutually exclusive. 
     
     
         27 . The method of  claim 20  wherein said frequency information includes Doppler shift information. 
     
     
         28 . The method of  claim 20  wherein said phase information includes coarse acquisition (“C/A”) code phase information.