GLOBAL POSITIONING APPARATUS AND METHOD FOR USING A TEMPERATURE COMPENSATED OSCILLATOR TO PERFORM A POSITION FIX

• US 20070120734A1
• Filed: 09/05/2006
• Published: 05/31/2007
• Est. Priority Date: 10/02/2001
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Salkhi, Amin
• Granted Patent: US 7,317,418 B2
• Time in Patent Office: Days
• US Class Current: 342/357.620
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• CPC Class Codes: G01S 19/34 Power consumption

Abstract

A global positioning receiver unit utilizes a temperature compensated oscillator and a unit controller. The temperature compensated oscillator generates a clock signal, and the unit controller is configured to track GPS time based on the clock signal while the receiver unit is in a sleep state. The unit controller is further configured to perform a position fix based on a satellite signal and the GPS time tracked by the unit controller.

Claims

1-15. -15. (canceled)

16. A global positioning system (GPS) satellite signal receiver, comprising:

a signal processing circuit for acquiring and tracking a plurality of GPS satellite signals;

a power control circuit coupled to the signal processing circuit, the power control circuit enabling power to be supplied to the signal processing circuit during an active state, and suspending power from being supplied to the signal processing circuit during a sleep state;

a timer for keeping track of a duration of the sleep state;

a temperature-compensated oscillator for generating a clock signal; and

a controller, coupled to the timer and receiving the clock signal, which (i) tracks a GPS time;

(ii) upon the signal processing circuit entering the active state from the sleep state, determines whether or not the duration of the sleep state exceeds a threshold value;

(iii) when duration of the sleep state does not exceed the threshold value, performs a position fix using the GPS satellite signals acquired and the GPS time; and

(iv) when the duration of the sleep state is less than the threshold, the controller, performs the position fix without relying on the GPS time.

19. A method for controlling operational power in a global positioning system (GPS) satellite signal receiver, comprising:

providing a signal processing circuit for acquiring and tracking a plurality of GPS satellite signals;

providing a power control circuit coupled to the signal processing circuit, the power control circuit enabling power to be supplied to the signal processing circuit during an active state, and suspending power from being supplied to the signal processing circuit during a sleep state;

providing a timer for keeping track of a duration of the sleep state;

providing a temperature-compensated oscillator for generating a clock signal; and

providing a controller, coupled to the timer and receiving the clock signal, which (i) tracks a GPS time;

(ii) upon the signal processing circuit entering the active state from the sleep state, determines whether or not the duration of the sleep state exceeds a threshold value;

(iii) when duration of the sleep state does not exceed the threshold value, performs a position fix using the GPS satellite signals acquired and the GPS time; and

(iv) when the duration of the sleep state is less than the threshold, the controller, performs the position fix without relying on the GPS time.

20. The method of claim 19, further comprising:

Providing a first power source for powering the signal processing circuit during the active state; and

Providing a second power source for powering the controller to track GPS time during the sleep state.

21. The method of claim 19, further comprising configuring a counter to receive the clock signal and to output the clock signal at a reduced frequency to the controller.