APPARATUS AND METHODS FOR MAINTAINING A RELIABLE TIME CLOCK ON A MOBILE COMPUTING DEVICE SUPPORTING SATELLITE BASED POSITION DETERMINATION CAPABILITY

• US 20090219205A1
• Filed: 02/28/2008
• Published: 09/03/2009
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Shi, Jianxiong, Jazra, Cherif
• Granted Patent: US 8,009,519 B2
• Time in Patent Office: Days
• US Class Current: 342/357.640
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G04R 20/02 the radio signal being sent by a satellite, e.g. GPS
• CPC Class Codes: G04R 20/14 the radio signal being a telecommunication standard signal, e.g. GSM

Abstract

Various embodiments for maintaining a reliable time clock on a mobile computing device are described. In one embodiment, a mobile computing device may optionally enable and disable acquisition of time data from multiple sources including a mobile network and a global positioning system (GPS) satellite. The mobile computing device may comprise a time clock to display local time information derived from stored time data and may prioritize the multiple sources for writing and overwriting the stored time data to converge to the most reliable time data available. Other embodiments are described and claimed.

Claims

1. A mobile computing device comprising a time clock to display local time information derived from stored time data, the mobile computing device optionally enabling and disabling acquisition of time data from multiple sources including a mobile network and a global positioning system (GPS) satellite, the mobile computing device to prioritize the multiple sources for writing and overwriting the stored time data to converge to the most reliable time data available.

2. The mobile computing device of claim 1, wherein time data broadcast by the mobile network is acquired automatically while acquisition of time data from the mobile network is enabled.

3. The mobile computing device of claim 1, wherein time data is acquired from sources other than the mobile network while acquisition of time data from the mobile network is disabled.

4. The mobile computing device of claim 3, wherein time data is input by a user of the mobile computing device.

5. The mobile computing device of claim 3, wherein time data is retrieved from a time server.

6. The mobile computing device of claim 1, wherein time data is acquired from the GPS satellite when a position fix is invoked to determine a current location of the mobile computing device.

7. The mobile computing device of claim 1, wherein the stored time data comprises at least time-of-day (TOD) data and date data, the mobile computing device to prioritize the GPS satellite over all other sources of TOD data and date data while acquisition of date and time from the GPS satellite is enabled.

8. The mobile computing device of claim 7, wherein previously acquired TOD data and date data is overwritten with current TOD data and date data derived from a signal broadcast by the GPS satellite.

9. The mobile computing device of claim 7, wherein TOD and date data derived from a signal broadcast by the GPS satellite cannot be overwritten with new TOD and date data acquired from a source other than the GPS satellite while acquisition of date and time from the GPS satellite is enabled.

10. The mobile computing device of claim 1, the time data stored by the time clock comprising time zone data and daylight savings time (DST) data, the mobile computing device to enable acquisition of time zone from the mobile network while acquisition of date and time from the GPS satellite is enabled.

11. The mobile computing device of claim 10, the mobile network having priority over all other sources of time zone data and DST data while acquisition of time zone from the mobile network is enabled.

12. The mobile computing device of claim 11, wherein previously acquired time zone data and DST data is overwritten with current time zone data and DST data acquired from the mobile network.

13. The mobile computing device of claim 11, wherein time zone data and DST data cannot be overwritten with new time zone data and DST data acquired from a source other than the mobile network while acquisition of time zone from the mobile network is enabled.

14. The mobile computing device of claim 10, the time clock to derive the local time from stored time data comprising current Coordinated Universal Time (UTC) data, time zone data representing a time zone offset to the UTC, and DST data representing a DST offset to the UTC.

15. The mobile computing device of claim 14, wherein the current UTC data is derived from GPS time and GPS-UTC correction information decoded from a signal broadcast by the GPS satellite and overwrites UTC data previously acquired from the mobile network, and the time zone data and DST data are broadcast by the mobile network.

17. The method of claim 11, further comprising acquiring time zone data from the mobile network.

18. The method of claim 11, further comprising acquiring daylight savings time (DST) data from the mobile network.

19. The method of claim 11, further comprising disabling acquisition of date and time from the mobile network.

20. The method of claim 19, further comprising acquiring TOD data and date data manually input by a user of the mobile computing device.

16. A method comprising:

enabling acquisition of time data by a mobile computing device from multiple sources including a mobile network and a global positioning system (GPS) satellite;

prioritizing the GPS satellite relative to the mobile network;

acquiring time data comprising time-of-day (TOD) data and date data broadcast by a mobile network;

storing the time data acquired from the mobile network;

deriving current TOD and date data from a decoded signal broadcast by the GPS satellite;

overwriting the TOD data and date data acquired from the mobile network with the current TOD data and date data time; and

displaying local time information derived from the stored time data comprising the current TOD data and date data time.

21. A computer-readable storage medium comprising executable computer program instructions that when executed enable a computing system to:

enable acquisition of time data by a mobile computing device from multiple sources including a mobile network and a global positioning system (GPS) satellite;

prioritize the GPS satellite relative to the mobile network;

acquire time data comprising time-of-day (TOD) data and date data broadcast by a mobile network;

store the time data acquired from the mobile network;

derive current TOD and date data from a decoded signal broadcast by the GPS satellite;

overwrite the TOD data and date data acquired from the mobile network with the current TOD data and date data time; and

display local time information derived from the stored time data comprising the current TOD data and date data time.

22. The computer-readable storage medium of claim 21, further comprising executable computer program instructions that when executed enable a computing system to acquire time zone data from the mobile network.

23. The computer-readable storage medium of claim 21, further comprising executable computer program instructions that when executed enable a computing system to acquire daylight savings time (DST) data from the mobile network.

24. The computer-readable storage medium of claim 21, further comprising executable computer program instructions that when executed enable a computing system to disable acquisition of date and time from the mobile network.

25. The computer-readable storage medium of claim 21, further comprising executable computer program instructions that when executed enable a computing system to acquire TOD data and date data manually input by a user of the mobile computing device.