Calibration and blanking in system simultaneously receiving GPS and GLONASS signals

• US 8,884,818 B1
• Filed: 04/05/2010
• Issued: 11/11/2014
• Est. Priority Date: 01/25/2010
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sun, Qinfang, Zhou, Hao
• Primary Examiner(s): Issing, Gregory C
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US12/754,577
• Time in Patent Office: 1,681 Days
• Field of Search: 342/357.63, 342/357.73, 342/357.77, 342/357.62, 342/357.72, 342/357.76
• US Class Current: 342/357.73
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• 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 simultaneously receiving Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) signals, the receiver comprising:

an analog front end (AFE) having at least a first filter, the AFE generating at least one analog-to-digital converted (ADC) output;

a digital front end (DFE) including a GPS path and a GLONASS path, the DFE receiving the at least one ADC output of the AFE, the GPS path having at least a second filter, the GLONASS path having at least a third filter;

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

search engines for receiving outputs of the DMI; and

calibration circuitry coupled to at least one of the first, second or third filters, wherein the calibration circuitry is configured to calibrate at least one of the first, second or third filters to correct for delays in components of the receiver and to cause a latency of the GPS and GLONASS signals to be equivalent.

2. The receiver of claim 1, wherein the calibration circuitry is configured to correct for delays in the AFE.

3. The receiver of claim 1, wherein the AFE includes a surface acoustic wave (SAW) filter.

4. The receiver of claim 1, wherein a temperature sensor is used to determine when calibration is required of the at least one of the first, second, or third filters in the receiver.

5. The receiver of claim 1, wherein a temperature sensor is used to adjust a correction amount used to correct for the delays.

6. The receiver of claim 1, wherein the AFE includes one or more intermediate frequency (IF) filters.

7. The receiver of claim 1, wherein a calibration signal is used to calculate a difference in the delays that is to be corrected by the calibration of the at least one of the first, second, or third filters in the receiver.

8. The receiver of claim 1, wherein the calibration circuitry is configured to correct for delays in the DFE.

9. The receiver of claim 8, wherein the DFE includes one or more baseband filters.

10. The receiver of claim 1, wherein correction for the delays is done using live GPS signals received during calibration.

11. A method for simultaneously receiving Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) signals, the method comprising:

with a receiver, receiving GPS and GLONASS signals simultaneously, the receiver having an analog front end (AFE), a digital front end (DFE), a dual mode interface (DMI), and search engines,

generating at least one analog-to-digital converted (ADC) output with the AFE, the AFE having at least a first filter,

receiving the at least one ADC output with the DFE, and generating a DFE output with the DFE, the DFE having a GPS path and a GLONASS path, the GPS path having at least a second filter, the GLONASS path having at least a third filter,

receiving the DFE output with the DMI, and producing signals for use by the search engines with the DMI; and

calibrating at least one of the first, second, or third filters in the receiver to correct for delays in components of the receiver and to cause a latency of the GPS and GLONASS signals to be equivalent.

12. The method of claim 11, the calibrating further comprising:

calibrating the first filter to correct for the delays and to cause the latency of the GPS and GLONASS signals to be equivalent.

13. The method of claim 11, wherein the first filter is a surface acoustic wave (SAW) filter.

14. The method of claim 11, the calibrating further comprising:

utilizing a temperature sensor to determine when calibration is required of the at least one of the first, second, and third filters in the receiver.

15. The method of claim 11, the calibrating further comprising:

utilizing a temperature sensor to adjust a correction amount used to correct for the delays.

16. The method of claim 11, wherein the AFE includes one or more intermediate frequency (IF) filters.

17. The method of claim 11, the calibrating further comprising:

generating a calibration signal to calculate a difference in the delays that is to be corrected by the calibrating the at least one of the first, second, or third filters in the receiver.

18. The method of claim 11, the calibrating further comprising:

calibrating the second and third filters to correct for the delays and to cause the latency of the GPS and GLONASS signals to be equivalent.

19. The method of claim 18, wherein the second and third filters are baseband filters.

20. The method of claim 11, the calibrating further comprising:

utilizing live GPS signals received during calibration to correct for the delays and to cause the latency of the GPS and GLONASS signals to be equivalent.

21. An electronic device for simultaneously receiving Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) signals, the electronic device comprising:

an analog front end (AFE) having at least a first filter, the AFE generating at least one analog-to-digital converted (ADC) output;

a digital front end (DFE) including a GPS path and a GLONASS path, the DFE receiving the at least one ADC output of the AFE, the GPS path having at least a second filter, the GLONASS path having at least a third filter;

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

search engines for receiving outputs of the DMI; and

calibration circuitry coupled to at least one of the first, second or third filters, wherein the calibration circuitry is configured to calibrate at least one of the first, second or third filters to correct for delays in components of the electronic device and to cause a latency of the GPS and GLONASS signals to be equivalent.

22. The electronic device of claim 21, wherein the calibration circuitry is configured to correct for delays in the AFE.

23. The electronic device of claim 21, wherein the AFE includes a surface acoustic wave (SAW) filter.

24. The electronic device of claim 21, wherein a temperature sensor is used to determine when calibration is required of the at least one of the first, second, or third filters in the electronic device.

25. The electronic device of claim 21, wherein a temperature sensor is used to adjust a correction amount used to correct for the delays.

26. The electronic device of claim 21, wherein the AFE includes one or more intermediate frequency (IF) filters.

27. The electronic device of claim 21, wherein a calibration signal is used to calculate a difference in the delays that is to be corrected by calibration of the at least one of the first, second, or third filters in the electronic device.

28. The electronic device of claim 21, wherein the calibration circuitry is configured to correct for delays in the DFE.

29. The electronic device of claim 28, wherein the DFE includes one or more baseband filters.

30. The electronic device of claim 21, wherein correction for the delays is done using live GPS signals received during calibration.