Analog Front End For System Simultaneously Receiving GPS and GLONASS Signals

• US 20110181467A1
• Filed: 04/05/2010
• Published: 07/28/2011
• Est. Priority Date: 01/25/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lin, Qiang, Samavati, Hirad, McFarland, William J., Sun, Qinfang
• Granted Patent: US 8,587,477 B2
• Time in Patent Office: Days
• US Class Current: 342/357.73
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain

Abstract

A receiver for receiving both GPS signals and GLONASS signals is provided. This receiver includes an analog front end (AFE), a GPS digital front end (DFE) and a GLONASS DFE for receiving an output of the AFE, and a dual mode interface (DMI) for receiving outputs of the GPS and GLONASS DFEs. Search engines are provided for receiving outputs of the DMI. Notably, certain front-end components of the AFE are configured to process both the GPS signals and the GLONASS signals.

Claims

1. A receiver for receiving GPS signals and GLONASS signals, the receiver comprising:

an analog front end (AFE);

a GPS digital front end (DFE) and a GLONASS DFE for receiving respective GPS and GLONASS outputs of the AFE;

a dual mode interface (DMI) for receiving outputs of the GPS and GLONASS DFEs; and

search engines for receiving outputs of the DMI,

wherein front-end components of the AFE are configured to process both the GPS signals and the GLONASS signals, wherein the AFE includes a single local oscillator (LO), a GPS polyphase filter, and a GLONASS polyphase filter, and wherein an LO frequency and a filter center frequency for at least one of the GPS polyphase filter and the GLONASS polyphase filter are tunable.

2. The receiver of claim 1, wherein the front-end components include a low noise amplifier (LNA).

3. The receiver of claim 1, wherein the front-end components include a single mixer set.

4. The receiver of claim 1, wherein the front-end components include a single I/Q mixer pair.

7. The receiver of claim 1, wherein the LO is dynamically tunable.

9. The receiver of claim 1, wherein the LO frequency and the filter center frequency are dynamically tunable.

10. The receiver of claim 1, wherein the LO is an integer-N synthesizer.

11. The receiver of claim 1, wherein passbands of the GPS polyphase filter and the GLONASS polyphase filter are selectable to be one of positive frequencies and negative frequencies.

12. The receiver of claim 11, wherein passband selection is one of static and dynamic.

13. The receiver of claim 1, wherein the AFE includes a GPS polyphase filter and a GLONASS polyphase filter, and wherein a filter bandwidth for each of the GPS polyphase filter and the GLONASS polyphase filter is tunable.

14. The receiver of claim 13, wherein the filter bandwidth is dynamically tunable.

16. The receiver of claim 1, wherein a frequency of the LO is set between GPS and GLONASS frequencies.

17. The receiver of claim 16, wherein the frequency of the LO is set such that a GPS intermediate frequency (IF) is below a GLONASS IF.

18. The receiver of claim 17, wherein the GPS IF is approximately between 1-6 MHz.

19. The receiver of claim 18, wherein the frequency of the LO is approximately 1581.67 MHz.

5. (canceled)

6. (canceled)

8. (canceled)

15. (canceled)

20. A method for generating a local oscillator (LO) frequency for a receiver configured to receive both GPS signals and GLONASS signals, the method comprising:

setting the LO frequency between GPS and GLONASS frequencies.

21. The method of claim 20, wherein the LO frequency is set such that a GPS intermediate frequency (IF) is below a GLONASS IF.

22. The method of claim 21, wherein the LO frequency is set such that the GPS IF is approximately between 1-6 MHz.

23. The method of claim 22, wherein the LO frequency is approximately 1581.67 MHz.

24. A method of operating a receiver configured to receive both GPS and GLONASS signals, the method comprising:

selecting an operation mode from one of a GPS-only mode, a GPS and GLONASS fixed mode, and a GPS and GLONASS dynamic mode,

wherein the GPS and GLONASS fixed mode has GPS and GLONASS always on, and

wherein the GPS and GLONASS dynamic mode has one of GPS and GLONASS always on, and another on based on predetermined conditions.

25. A receiver for simultaneously receiving GPS and GLONASS signals, the receiver comprising:

an analog front end (AFE);

a digital front end (DFE) including a GPS path and a GLONASS path, the DFE receiving an output of the AFE;

a dual mode interface (DMI) for receiving outputs of the DFE;

search engines for receiving outputs of the DMI; and

deactivation circuitry for deactivating dedicated circuitry of the DFE and the DMI when one of the GPS and the GLONASS signals is not needed.

26. The receiver of 25, wherein the deactivation circuitry is controlled by a navigation engine.

27. A receiver for simultaneously receiving GPS and GLONASS signals, the receiver comprising:

an analog front end (AFE);

a digital front end (DFE) including a GPS path and a GLONASS path, the DFE receiving an output of the AFE;

a dual mode interface (DMI) for receiving outputs of the DFE;

search engines for receiving outputs of the DMI; and

deactivation circuitry for deactivating dedicated circuitry of a first system when signals solely from a second system provide position determination.

28. (canceled)