Method and apparatus for determining a position of a gnss receiver

Abstract

A method of determining a position of a GNSS receiver includes: receiving, at the GNSS receiver, information from at least two GNSS satellites and an estimated location area from a non-GNSS positioning application, determining candidate pseudoranges corresponding to candidate correlation peaks determined based on the information received from the at least two GNSS satellites; determining possible positions of the GNSS receiver using the candidate pseudoranges and the estimated location area; determining a best possible position of the GNSS receiver from the possible positions; and setting the best possible position as the position of the GNSS receiver; wherein when multiple candidate correlation peaks corresponding to one of the at least two GNSS satellites are determined, the estimated location area is usable to reduce the number of candidate correlation peaks prior to candidate pseudoranges being determined.

1 . A method of determining a position of a GNSS receiver comprising:
 receiving, at the GNSS receiver, information from at least two GNSS satellites;   receiving, at the GNSS receiver, an estimated location area from a non-GNSS positioning application;   determining candidate pseudoranges corresponding to candidate correlation peaks determined based on the information received from the at least two GNSS satellites;   determining possible positions of the GNSS receiver using the candidate pseudoranges and the estimated location area;   determining a best possible position of the GNSS receiver from the possible positions; and   setting the best possible position as the position of the GNSS receiver;   wherein when multiple candidate correlation peaks corresponding to one of the at least two GNSS satellites are determined, the estimated location area is usable to reduce the number of candidate correlation peaks prior to candidate pseudoranges being determined.   
     
     
         2 . A method as claimed in  claim 1 , wherein determining a best possible position from the possible positions comprises: using a misclosure vector representing differences between the candidate pseudoranges and the possible positions and an indication of pseudorange quality. 
     
     
         3 . A method as claimed in  claim 1 , wherein the indication of pseudorange quality is based on received signal strength and satellite elevation of the GNSS satellite associated with the pseudorange. 
     
     
         4 . A computer readable medium comprising instructions executable on a processor for implementing the method of  claim 1 . 
     
     
         5 . A method as claimed in  claim 1 , wherein the information from at least two GNSS satellites and the estimated location area from the non-GNSS positioning application are received at generally the same time. 
     
     
         6 . A method as claimed in  claim 1 , wherein the non-GNSS positioning application is an application capable of providing an initial position. 
     
     
         7 . A method as claimed in  claim 5 , wherein the non-GNSS positioning application is based on one of: WiFi, Cellular, land-mobile radio, radio broadcast and GeoIP. 
     
     
         8 . A method as claimed in  claim 1 , comprising receiving GNSS satellite information from a GNSS receiver of another mobile device. 
     
     
         9 . A method as claimed in  claim 1 , wherein at least one of the candidate pseudoranges corresponds to an acquired one of the GNSS satellites. 
     
     
         10 . A mobile device comprising:
 an antenna;   a GNSS receiver for receiving information from at least two GNSS satellites and for receiving an estimated location area from a non-GNSS positioning application; and   a processor in communication with the GNSS receiver; the processor determining candidate pseudoranges corresponding to candidate correlation peaks determined based on the information received from the at least two GNSS satellites, determining a best possible position of the GNSS receiver from possible positions of the GNSS receiver determined using the candidate pseudoranges and the estimated location area and setting the best possible position as the position of the GNSS receiver;   wherein when multiple candidate correlation peaks corresponding to one of the at least two GNSS satellites are determined, the estimated location area is usable to reduce the number of candidate correlation peaks prior to candidate pseudoranges being determined.   
     
     
         11 . A mobile device as claimed in  claim 10 , wherein the processor receives GNSS satellite information from a GNSS receiver of another mobile device. 
     
     
         12 . A mobile device as claimed in  claim 10 , wherein at least one of the candidate pseudoranges corresponds to an acquired one of the GNSS satellites.