Satellite navigation receiver having configurable acquisition and tracking engines

• US 7,705,778 B2
• Filed: 10/30/2008
• Issued: 04/27/2010
• Est. Priority Date: 06/27/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Yeh, Wen-Chang, Sun, Qinfang
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US12/261,896
• Publication Number:
  US 20090322599A1
• Time in Patent Office: 544 Days
• Field of Search: 342/357.12, 342/357.15
• US Class Current: 342/357.69
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• 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 satellite navigation receiver having a flexible acquisition and tracking engine architecture. The flexible acquisition engine has a reconfigurable delay line that can be used either as a single entity or divided into different sections. Consequently, it can be configured to search different satellite vehicles, a single Doppler frequency, and full CA code in parallel. When configuring the delay line into different sections, each section is used to search a partial CA code. In this configuration, multiple Doppler mode, multiple satellite vehicles, multiple Doppler frequencies, and partial CA code can be searched in parallel. Furthermore, the different sections of the CA code can be time-multiplexed into a correlator, which can then be over clocked to achieve full CA code correlation. The flexible tracking engine includes a number of parallel tracking channels, whereby each individual channel has a number of taps or fingers, which can be used to lock onto different delays. During tracking, one of the taps can be used to lock on to the center of the peak. This leaves the other taps free to be used to perform other functions, such as determining the shape of the peak, detecting earlier arrivals for line of sight component, and obtaining an estimate of the noise floor. The flexible tracking engine is configurable to help acquisition functions, such as fine acquisition, false trigger detection, and/or fast reacquisition.

Claims

1. A satellite navigation receiver comprising:

an analog section for performing analog signal processing on a received satellite navigation signal;

a tracking engine coupled to the analog section that tracks the satellite navigation signal, wherein the tracking engine comprises a plurality of tracking channels, each tracking channel having a configurable plurality of taps that can be used to lock on to a plurality of different delays, wherein a spacing between the taps is determined by a desired search range; and

a processor coupled to the tracking engine that processes data to provide location information.

2. The satellite navigation receiver of claim 1, wherein one of the taps is locked to a center of a correlation peak.

3. The satellite navigation receiver of claim 2, wherein one of the taps is used to determine a shape of the correlation peak.

4. The satellite navigation receiver of claim 3, wherein the shape of the correlation peak is used to compute a discriminator for a delay lock loop in fine timing adjustment.

5. The satellite navigation receiver of claim 2, wherein one of the taps is used to detect earlier arrivals for an LOS component.

6. The satellite navigation receiver of claim 2, wherein one of the taps is used to correlate with wrong timing in order to obtain an estimate of a noise floor.

7. The satellite navigation receiver of claim 1, wherein the tracking engine performs fine acquisition.

8. The satellite navigation receiver of claim 7, wherein fine acquisition searches a Doppler frequency and code phase around a coarse acquisition peak to reduce an estimation error.

9. The satellite navigation receiver of claim 1, wherein the tracking engine detects false triggers.

10. The satellite navigation receiver of claim 9, wherein the false triggers are determined by searching a range around top correlation peaks using a longer integration.

11. The satellite navigation receiver of claim 1, wherein the tracking engine performs a fast reacquisition.

12. The satellite navigation receiver of claim 11, wherein a search is performed within a small range of parameters corresponding to the last known location of an SV.

13. The satellite navigation receiver of claim 1 further comprising an acquisition engine that acquires the satellite navigation signal, wherein the acquisition engine performs an acquisition search while the tracking engine performs functions that can be used to perform fine acquisition, false trigger detection, or fast reacquisition.

14. The satellite navigation receiver of claim 1, further comprising an acquisition engine that acquires the satellite navigation signal, wherein the tracking engine further performs acquisition tasks in the tracking engine.

15. A GPS receiver comprising:

an analog section for performing analog signal processing on a received satellite navigation signal;

a tracking engine coupled to the analog section that tracks the satellite navigation signal, wherein the tracking engine comprises a plurality of tracking channels, each tracking channel operable to search for one Doppler frequency and a configurable plurality of code phases in parallel, wherein a spacing between the plurality of code phases is determined by a desired search range; and

a processor coupled to the tracking engine that processes data to provide location information.

16. The GPS receiver of claim 15, wherein the tracking engine comprises sixteen tracking channels and seven code phases.

17. The GPS receiver of claim 15, further comprising an acquisition engine that acquires the satellite navigation signal, wherein the acquisition engine performs an acquisition search while the tracking engine performs functions that may be used to perform at least one of:

fine acquisition, false trigger detection, and fast reacquisition.

18. A method of determining a location of a GPS receiver comprising:

acquiring a signal from a GPS satellite;

searching for one Doppler frequency and a configurable plurality of CA code phases in parallel, wherein a spacing between the plurality of CA code phases is determined by a desired search range; and

generating location information based on the searching step.

19. The method of claim 18 further comprising determining a shape of a peak correlation.

20. The method of claim 18 further comprising detecting early arrivals for a LOS component.

21. The method of claim 18 further comprising obtaining an estimate of a noise floor by correlating to a wrong timing.

22. The method of claim 18 further comprising using a tracking channel to perform some acquisition functions.

23. The method of claim 22, wherein the acquisition functions include performing fine acquisition.

24. The method of claim 22, wherein the acquisition functions include detecting false triggers.

25. The method of claim 22, wherein the acquisition functions include reacquiring the signal.

26. The method of claim 18, wherein the signal is acquired by an acquisition engine and the searching is performed by a tracking engine.