Background crystal oscillator calibration

• US 10,397,887 B2
• Filed: 01/26/2018
• Issued: 08/27/2019
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wu, Jie, Filipovic, Daniel Fred, Simic, Emilija Milorad, Agarwal, Vishal
• Primary Examiner(s): Urban, Edward F
• Assistant Examiner(s): Mathew, Max
• Application Number:
  US15/881,685
• Publication Number:
  US 20180160381A1
• Time in Patent Office: 578 Days
• Field of Search: 455 6711, 34235762, 331 73, 331 74, 331154, 331158
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: H03L 1/022 by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature H03L1/021 takes precedence
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

System and method for temperature-calibration of a crystal oscillator (XO) in a mobile device. A temperature-calibration status of the XO is determined and a trigger condition related to temperature-calibration of the XO is detected. If the temperature-calibration status of the XO is not fully temperature-calibrated or if the XO has not been previously temperature-calibrated, a temperature-calibration session is initiated by an XO manager based on the condition, wherein a receiver is configured to receive signals and temperature-calibration of the XO is performed in a background mode based on the received signals. The condition based triggering ensures that the XO is temperature-calibrated prior to launch of any position based or global navigation satellite systems (GNSS) based applications on the mobile device. The trigger condition can include first use or power-on, charging, presence in an outdoor environment, variation in operating temperature, pre-specified time, and/or user input pertaining to the mobile device.

Claims

1. A method of temperature-calibrating a non-temperature compensated crystal oscillator (XO) in a mobile device, the method comprising:

determining that a temperature-calibration status of the XO is not fully temperature-calibrated;

detecting a trigger condition related to temperature-calibration of the XO; and

initiating a temperature-calibration session, wherein the temperature-calibration session comprises;

receiving wireless signals based on the trigger condition; and

temperature-calibrating the XO in a background mode based on the received wireless signals, wherein the mobile device is configured to execute position based applications or global navigation satellite systems (GNSS) based applications, and the background mode is independent from the position based applications or global navigation satellite systems (GNSS) based applications.

2. The method of claim 1, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source.

3. The method of claim 1, wherein the trigger condition comprises one or more of:

a first use of the mobile device, wherein the first use is associated with powering on the mobile device;

an imminent launch of a position based application or global navigation satellite systems (GNSS) based application on the mobile device;

charging the mobile device;

comprises detecting presence of the mobile device in an outdoor location;

or

a variation in operating temperature of the mobile device.

4. The method of claim 1, further comprising updating the temperature-calibration status of the XO as completed, detecting a second trigger condition, and suppressing the second trigger condition based on the updated temperature-calibration status.

5. The method of claim 1, further comprising recording a first time associated with temperature-calibrating the XO, detecting a second trigger condition and if a pre-specified time has lapsed since the first time, initiating a second temperature-calibration session.

6. The method of claim 1, wherein the trigger condition comprises detecting at least one global navigation satellite systems (GNSS) signal.

7. The method of claim 6, wherein the trigger condition is further based on a signal strength of the least one GNSS signal.

8. A mobile device comprising:

a non-temperature compensated crystal oscillator (XO);

a receiver; and

a processor configured to;

determine a temperature-calibration status of the XO is not fully temperature-calibrated;

detect a trigger condition related to temperature-calibration of the XO; and

initiate a temperature-calibration session, wherein the temperature-calibration session comprises;

enabling the receiver to receive wireless signals based on the trigger condition; and

temperature-calibrating the XO in a background mode based on the received wireless signals, wherein the mobile device is configured to execute position based applications or global navigation satellite systems (GNSS) based applications, and the background mode is independent from the position based applications or global navigation satellite systems (GNSS) based applications.

9. The mobile device of claim 8, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source.

10. The mobile device of claim 8, wherein the trigger condition comprises one or more of:

a first use of the mobile device, wherein the first use is associated with powering on the mobile device;

an imminent launch of a position based application or global navigation satellite systems (GNSS) based application on the mobile device;

charging the mobile device;

comprises detecting presence of the mobile device in an outdoor location;

or

a variation in operating temperature of the mobile device.

11. The mobile device of claim 8, further comprising a status register configured to store the temperature-calibration status of the XO, wherein the processor is further configured to update the temperature-calibration status of the XO in the status register as temperature-calibrated, detect a second trigger condition, and suppress the second trigger condition based on the updated temperature-calibration status stored in the status register.

12. The mobile device of claim 8, further comprising a memory configured to store a first time associated with temperature-calibrating the XO, wherein the processor is further configured to read the first time from the memory upon detecting a second trigger condition and initiate a second temperature-calibration session if a pre-specified time has lapsed since the first time.

13. The mobile device of claim 8, integrated in at least one semiconductor die.

14. The mobile device of claim 8, integrated into a device, selected from a group consisting of a set-top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, and a computer.

15. The mobile device of claim 8, wherein the trigger condition comprises detecting at least one global navigation satellite systems (GNSS) signal.

16. The mobile device of claim 15, wherein the trigger condition is further based on a signal strength of the least one GNSS signal.

17. A wireless communication system comprising:

a non-temperature compensated crystal oscillator (XO);

means for receiving wireless signals;

means for determining that a temperature-calibration status of the XO is not fully temperature-calibrated;

means for detecting a trigger condition related to temperature-calibration of the XO; and

means for initiating a temperature-calibration session, wherein the temperature-calibration session comprises;

enabling the means for receiving wireless signals based on the trigger condition; and

temperature-calibrating the XO in a background mode based on the received wireless signals, wherein the wireless communication system comprises means for executing position based applications or global navigation satellite systems (GNSS) based applications, and the background mode is independent from the position based applications or global navigation satellite systems (GNSS) based applications.

18. The wireless communication system of claim 17, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source.

19. The wireless communication system of claim 17, wherein the trigger condition comprises one or more of:

a first use of the wireless communication system, wherein the first use is associated with powering on the wireless communication system;

an imminent launch of a position based application or global navigation satellite systems (GNSS) based application on the wireless communication system;

charging the wireless communication system;

comprises detecting presence of the wireless communication system in an outdoor location;

or

a variation in operating temperature of the wireless communication system.

20. The wireless communication system of claim 17, further comprising means for storing the temperature-calibration status of the XO, and means for suppressing a second trigger condition based on the stored temperature-calibration status.

21. The wireless communication system of claim 17, further comprising means for recording a first time associated with temperature-calibrating the XO, means for detecting a second trigger condition, and means for initiating a second temperature-calibration session if a pre-specified time has lapsed since the first time.

22. A non-transitory computer-readable storage medium comprising code, which, when executed by a processor, causes the processor to perform operations for temperature-calibrating of a non-temperature compensated crystal oscillator (XO) in a mobile device, the non-transitory computer-readable storage medium comprising:

code for determining that a temperature-calibration status of the XO is not fully temperature-calibrated;

code for detecting a trigger condition related to temperature-calibration of the XO; and

code for initiating a temperature-calibration session, wherein the temperature-calibration session comprises;

receiving wireless signals based on the trigger condition; and

temperature-calibrating the XO in a background mode based on the received wireless signals, wherein the mobile device is configured to execute position based applications or global navigation satellite systems (GNSS) based applications, and the background mode is independent from the position based applications or global navigation satellite systems (GNSS) based applications.

23. The non-transitory computer-readable storage medium of claim 22, wherein the received wireless signals comprise one or more of global navigation satellite systems (GNSS) signals, signals from a calibrated terrestrial source, or signals from a geo-stationary source.

24. The non-transitory computer-readable storage medium of claim 22, wherein the trigger condition comprises one or more of:

a first use of the mobile device, wherein the first use is associated with powering on the mobile device;

an imminent launch of a position based application or global navigation satellite systems (GNSS) based application on the mobile device;

charging the mobile device;

comprises detecting presence of the mobile device in an outdoor location;

or

a variation in operating temperature of the mobile device.

25. The non-transitory computer-readable storage medium of claim 22, further comprising code for storing the temperature-calibration status of the XO, and code for suppressing a second trigger condition based on the stored temperature-calibration status.

26. The non-transitory computer-readable storage medium of claim 22, further comprising code for recording a first time associated with temperature-calibrating the XO, code for detecting a second trigger condition, and code for initiating a second temperature-calibration session if a pre-specified time has lapsed since the first time.