GPS Enhancement for Wireless Devices

Abstract

Methods and systems are disclosed to help improve accuracy of location determination for a wireless communication device. An exemplary method involves: (a) at a wireless communication device operating in a radio access network, making a determination that the wireless communication device is likely to lose global positioning system (GPS) connectivity; (b) in response to the determination, powering on a GPS receiver to receive GPS location data for the wireless communication device; and (c) powering off the GPS receiver and storing the received GPS location data.

1 . A method comprising:
 at a wireless communication device operating in a radio access network, making a determination that the wireless communication device is located at a location where the wireless communication device is likely to lose global positioning system (GPS) connectivity;   in response to the determination:
 (i) operating a GPS receiver to receive GPS location data for the wireless communication device; and 
 (ii) powering off the GPS receiver and storing the received GPS location data. 
   
     
     
         2 . The method of  claim 1 , wherein making the determination that the wireless communication device is located at a location where the wireless communication device is likely to lose GPS connectivity comprises receiving a user input indicating that the user is about to enter a non-GPS zone. 
     
     
         3 . The method of  claim 1 , wherein making the determination that the wireless communication device is located at a location where the wireless communication device is likely to lose GPS connectivity comprises determining that the sector in which the WCD is located is a GPS-priority sector for the WCD. 
     
     
         4 . The method of  claim 3 , wherein determining that the sector in which the WCD is located is a GPS-priority sector for the WCD is performed in response to the WCD entering the sector. 
     
     
         5 . The method of  claim 1 , further comprising the WCD initially:
 generating GPS-availability data identifying GPS-priority sectors for the WCD; and   at least one of (a) storing the GPS-availability data in data storage at the WCD and (b) transmitting the GPS-availability data to the RAN to be stored in data storage at the RAN;   wherein making the determination that the wireless communication device is located at a location where the wireless communication device is likely to lose GPS connectivity comprises determining that the WCD is operating in a GPS-priority sector.   
     
     
         6 . The method of  claim 5 , wherein generating the GPS-availability data identifying GPS-priority sectors for the WCD comprises, during a setup period of a predetermined duration, periodically:
 powering on the GPS receiver and making a determination as to whether or not a GPS signal is available to the WCD;   if a GPS signal not available, then:
 (i) identifying which sector of the RAN the WCD is operating in; and 
 (ii) generating GPS-availability data indicating that the sector is a GPS-priority sector for the WCD. 
   
     
     
         7 . The method of  claim 5 , wherein generating the GPS-availability data identifying GPS-priority sectors for the WCD comprises, during a setup period of a predetermined duration:
 monitoring GPS connectivity for the WCD; and   detecting when GPS connectivity is unavailable to the WCD and identifying one or more sectors in which the WCD is located when GPS connectivity is unavailable.   
     
     
         8 . The method of  claim 7 , wherein generating the GPS-availability data identifying GPS-priority sectors for the WCD further comprises creating a data entry for each sector where GPS connectivity was indicated to be unavailable, wherein the data entry indicates the sector is a GPS-priority sector. 
     
     
         9 . The method of  claim 7 , wherein generating the GPS-availability data identifying GPS-priority sectors for the WCD further comprises:
 determining, for each of the sectors, a corresponding non-GPS level indicating how often or how many times GPS connectivity was unavailable during the setup period;   wherein the non-GPS level is above a predetermined threshold then generating a data entry indicating that the corresponding sector is a GPS-priority sector.   
     
     
         10 . The method of  claim 1 , wherein making the determination that the wireless communication device is located at a location where the wireless communication device is likely to lose GPS connectivity comprises:
 identifying which sector of the RAN the WCD is operating in; and   accessing a GPS-availability database to determine whether or not the sector in which the RAN is operating is a GPS-priority sector, wherein operating in the GPS-priority sector indicates that the wireless communication device is likely to lose GPS connectivity.   
     
     
         11 . The method of  claim 1 , wherein the wireless communication device, by default, operates with the GPS receiver powered off, when not performing the method of  claim 1 . 
     
     
         12 . The method of  claim 1 , wherein the wireless communication device enters a non-GPS zone and loses GPS connectivity, the method further comprising:
 while the wireless communication device is located in the non-GPS zone without GPS connectivity, transmitting the stored GPS location data to a radio access network.   
     
     
         13 . The method of  claim 1 , the method further comprising, after powering off the GPS receiver, using at least one of (a) a compass and an accelerometer and (b) trilateration data based on signals from a plurality of nearby base stations to track location of the wireless communication device from the stored GPS location data. 
     
     
         14 . The method of  claim 1 , wherein the WCD performs the method of  claim 1  in order to store the last-available GPS coordinates before entering a non-GPS zone. 
     
     
         15 . A method comprising:
 at a radio access network configured to provide wireless service to a wireless communication device in a plurality of sectors, identifying one or more GPS-priority sectors where the wireless communication device is likely to lose GPS connectivity;   making a determination that the wireless communication device is located in one of the GPS-priority sectors; and   in response to the determination, transmitting a message to the wireless communication device that indicates that the wireless communication device is located in one of the GPS-priority sectors, thereby causing the wireless communication device to operate a GPS receiver to receive GPS location data for the wireless communication device, store the received GPS location data, and then power off the GPS receiver.   
     
     
         16 . The method of  claim 15 , wherein identifying one or more GPS-priority sectors where the wireless communication device is likely to lose GPS connectivity comprises receiving GPS-availability data from a wireless communication device, wherein the GPS-availability data indicates one or more GPS-priority sectors. 
     
     
         17 . The method of  claim 15 , wherein identifying one or more GPS-priority sectors where the wireless communication device is likely to lose GPS connectivity comprises:
 identifying one or more non-GPS zones associated with the subscriber; and   determining the sector in which each of the non-GPS zones is located.   
     
     
         18 . The method of  claim 17 , wherein the one or more non-GPS zones associated with the subscriber comprise at least one of (a) a billing address of the subscriber, (b) a home address of the subscriber, and (c) a work address of the subscriber. 
     
     
         19 . The method of  claim 15 , wherein identifying one or more GPS-priority sectors where the wireless communication device is likely to lose GPS connectivity comprises identifying one or more general GPS-priority sectors. 
     
     
         20 . A system comprising:
 a non-transitory computer readable medium; and   program logic stored in the non-transitory computer readable medium and executable by the at least one processor to:
 (a) determine that a wireless communication device is located at a location where the wireless communication device is likely to lose global positioning system (GPS) connectivity; and 
 (b) in response to a determination that the wireless communication device is located at a location where the wireless communication device is likely to lose GPS connectivity:
 (i) operate a GPS receiver to receive GPS location data for the wireless communication device; 
 (ii) store the received GPS location data in the data storage; and 
 (iii) power off the GPS receiver. 
 
   
     
     
         21 . The system of  claim 20 , further comprising program logic stored in the non-transitory computer readable medium and executable by the at least one processor to maintain a GPS-availability database indicating GPS-priority sectors for the wireless communication device.