Intelligent global positioning system (GPS) information detection

• US 8,543,130 B2
• Filed: 02/29/2008
• Issued: 09/24/2013
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Golds, David
• Primary Examiner(s): Afshar, Kamran
• Assistant Examiner(s): Fahnert, Marisol
• Application Number:
  US12/040,862
• Publication Number:
  US 20090054078A1
• Time in Patent Office: 2,034 Days
• Field of Search: 4554561-4566, 455/3.02, 455/161.3, 455/181.1, 455/404.2, 455/440, 3423572-35778, 701200-226, 701400-425
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/34 Power consumption

Abstract

Intelligently caching global positioning system (GPS) location information from GPS satellites based on cellular radio signal strength received at a portable device. The GPS satellites broadcasts signals to the portable device and the cellular radio signal strength is at a first level indicative of a low GPS reception strength. A second level, at the portable device, of the cellular radio signal strength is detected, and the second level is indicative of an increase in GPS reception strength. GPS location information is speculatively read from the GPS satellites associated with the portable device in response to the detected second level and the increase of the GPS reception strength. The GPS location information is cached on the portable device such that the GPS location information is available to the portable device when the first level of the cellular radio signal strength is less than the second level.

Claims

1. A method for intelligently caching global positioning system (GPS) location information from GPS satellites, wherein the GPS satellites broadcast GPS signals to a portable device, said portable device receiving broadcasted signals as a function of a cellular radio signal strength, wherein the cellular radio signal strength is initially at a first level indicative of a low GPS signal reception strength, said method comprising:

detecting a second level of the cellular radio signal strength at the portable device, said second level indicative of an increase in GPS reception strength when the second level is greater than the first level;

when the second level is greater than the first level;

activating a timer when GPS location information is determined to be stale;

speculatively reading GPS location information from the GPS satellites associated with the portable device in response to the timer when the GPS reception strength increases, wherein the reading occurs within a pre-set time interval; and

storing the read GPS location information on the portable device;

when the second level is less than or equal to the first level;

activating a timer, said timer deactivating the detecting; and

permitting access, by the portable device, to the stored GPS location information;

providing a timestamp to the stored GPS location information on the portable device; and

removing the stored GPS location information on the portable device after a pre-determined period of time has lapsed with respect to the timestamp.

2. The method of claim 1, wherein detecting comprises detecting the GPS signal reception strength in response to the timer.

3. A system for intelligently caching global positioning system (GPS) location information on a portable device, said portable device being configured for receiving signals broadcast by a GPS satellite and determining a location of the portable device as a function thereof, said system comprising:

a transceiver adapted for receiving and transmitting signals from the GPS satellite;

a processor configured to execute computer-executable instructions for;

determining an increase in the GPS satellite signal strength received from the GPS satellite via the transceiver from a first level to a second level, said second level corresponding to at least a minimum signal strength for determining the location of the portable device;

determining when the GPS location information is stale;

reading a current location of the portable device in response to the determined increase in the GPS signal strength to the second level as received at the portable device and the GPS location information being stale, wherein the reading occurs within a pre-set time interval; and

a memory for caching, on the portable device, the read current location information of the portable device based on a timestamp of the read current location information provided by the processor;

wherein the processor is configured to monitor the GPS satellite signal strength from the first level to the second level and wherein the memory stores the monitored GPS satellite signal strength information, wherein the memory removes the monitored GPS satellite signal strength information after a pre-determined period of time has lapsed; and

wherein the processor is further configured to retrieve the read location information from the memory when the transceiver is unable to receive signals from the GPS satellite at a next location and to provide the read current location information.

4. The system of claim 3, wherein the processor is further configured to activate a timer if the second level is less than or equal to the first level, wherein the timer deactivates determining.

5. The system of claim 4, wherein the processor is configured to speculatively read the GPS location information in response to the timer.

6. The system of claim 3, wherein the processor determines the monitored GPS satellite signal strength from the first level to the second level, said second level corresponding to at least the minimum signal strength for determining the location of the portable device.

7. A method for intelligently caching global positioning system (GPS) location information from GPS satellites, wherein the GPS satellites broadcasting GPS signals to a portable device, said portable device receiving broadcasted signals as a function of a cellular radio signal strength, wherein the cellular radio signal strength is initially at a first level indicative of a low GPS signal reception strength, said method comprising:

determining when the GPS location information is stale;

monitoring the cellular radio signal strength at the portable device;

detecting a second level of the monitored cellular radio signal strength at the portable device, said second level indicative of an increase in GPS reception strength when the second level is greater than the first level;

speculatively reading GPS location information from the GPS satellites associated with the portable device in response to the detected second level and the increase of the GPS reception strength and the GPS location information being stale, wherein the reading occurs within a pre-set time interval;

storing the read GPS location information on the portable device as a function of the cellular radio signal strength received at the portable device such that the read GPS location information is available to the portable device at times when the GPS location information is unavailable for update from the GPS satellites due to the low GPS reception strength at the first level;

providing a timestamp to the stored GPS location information on the portable device; and

removing the stored GPS location information after a pre-determined period of time has lapsed with respect to the timestamp.

8. The method of claim 7, further comprising activating a timer if the second level is less than or equal to the first level, wherein the timer deactivates detecting.

9. The method of claim 8, wherein speculatively reading comprises speculatively reading the GPS location information in response to the timer.