Signal detector employing correlation analysis of non-uniform and disjoint sample segments

• US 7,002,516 B2
• Filed: 08/19/2003
• Issued: 02/21/2006
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Gronemeyer, Steven A.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/644,311
• Publication Number:
  US 20050035905A1
• Time in Patent Office: 917 Days
• Field of Search: 455/403, 455/422.1, 455/426.1, 455427-430, 4554561-4566, 455/457, 375130-153, 375224-236, 375340-343, 342/378, 34235701-35717, 705/1
• US Class Current: 342/378
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence

Abstract

A wireless communication device (e.g., a cellular telephone) includes one transceiver for voice or data communication and a global positioning system (GPS) receiver a signal for receiving a GPS signal from the GPS satellites. The GPS receiver does not receive the GPS signal when the transceiver is transmitting, so that the GPS signal receives may consist of multiple signal segments of various duration and various delays. A method is provided which combine correlations of these multiple signal segments cumulatively until a sufficiently signal-to-noise ratio is achieved to allow detection of the transmitted signal of one or more of the GPS satellites.

Claims

1. A wireless communication device, comprising at least one component including at least one transceiver supporting voice communication, a Global Positioning System (GPS) receiver, and at least one signal processor, the components producing position information of the device by receiving a control signal that is generated in response to at least one event, controlling at least one of receipt and processing of at least one signal in response to a state of the control signal, performing correlation analyses of multiple segments of the received signal from separate and distinct periods of time, generating cumulative correlation data by combining selected results of the correlation analyses, and maintaining at least one parameter of the at least one received signal across a time period of the at least one event using the cumulative correlation data.

2. The device of claim 1, wherein the at least one event includes at least one of transmission by at least one local transmitter, blanking the received signal, detected interference of the received signal, a signal-to-noise ratio of the received signal being below a threshold, voltage magnitudes that exceed prespecified thresholds, and rates of change of voltages that exceed prespecified thresholds.

3. The device of claim 1, wherein the at least one parameter includes at least one of carrier signal frequency, carrier signal phase, code frequency, and code phase.

4. The device of claim 1, wherein the components further include at least one local signal generator that maintains a state of a local GPS replica waveform during the at least one event.

5. The device of claim 1, wherein controlling at least one of receipt and processing includes receiving a first segment and a second segment of the signal, wherein the signal includes at least one of noise and pseudo-noise and the first and second segments represent samples of the signal during first and second periods of time.

6. The device of claim 1, further comprising:

a hypothesis generator that generates at least one hypothesis; and

at least one matched filter that performs the correlation analyses, wherein the correlation analyses includes generating first correlation data representative of a correlation between at least one first segment of the signal and the hypothesis, and second correlation data representative of a correlation between at least one second segment of the signal and the hypothesis.

7. The device of claim 1, further comprising at least one matched filter that determines a parameter difference between correlation data of the correlation analyses and adjusts selected correlation data responsive to the parameter difference, wherein generating cumulative correlation data comprises combining the adjusted correlation data with the correlation data.

8. The device of claim 1, wherein generating cumulative correlation data includes adjusting selected correlation data of the correlation analyses by shifting the selected correlation data in response to a difference in the at least one parameter.

9. The device of claim 1, wherein the received signal is a carrier signal modulated with at least one code.

10. A communication system, comprising:

means for receiving a control signal that is generated in response to at least one event;

means for controlling at least one of receipt and processing of at least one signal in response to a state of the control signal;

means for performing correlation analyses of multiple segments of the received signal from separate and distinct periods of time;

means for generating cumulative correlation data by combining selected results of the correlation analyses; and

means for maintaining at least one parameter of the at least one received signal across a time period of the at least one event using the cumulative correlation data.

11. The system of claim 10, further comprising means for maintaining at least one local time reference signal during the at least one event, the local time reference signal related to a time base of a transmitter of the received signal.

12. The system of claim 10, further comprising means for generating at least one hypothesis, wherein the correlation analyses includes generating first correlation data representative of a correlation between at least one first segment of the signal and the hypothesis, and second correlation data representative of a correlation between at least one second segment of the signal and the hypothesis.

13. The system of claim 10, further comprising means for determining a parameter difference between correlation data of the correlation analyses and adjusting selected correlation data responsive to the parameter difference, wherein generating cumulative correlation data comprises combining the adjusted correlation data with the correlation data.

14. The system of claim 10, wherein generating cumulative correlation data includes adjusting selected correlation data of the correlation analyses by shifting the selected correlation data in response to a difference in the at least one parameter.

15. A method for at least one of detecting and tracking signals, comprising:

receiving a control signal that is generated in response to at least one event;

controlling at least one of receipt and processing of at least one signal in response to a state of the control signal;

performing correlation analyses of multiple segments of the received signal from separate and distinct periods of time;

generating cumulative correlation data by combining selected results of the correlation analyses; and

maintaining at least one parameter of the at least one received signal across a time period of the at least one event using the cumulative correlation data.

16. The method of claim 15, wherein the received signal is a carrier signal modulated with at least one code.

17. The method of claim 15, wherein the at least one event includes at least one of transmission by at least one local transmitter, blanking the received signal, detected interference of the received signal, a signal-to-noise ratio of the received signal being below a threshold, voltage magnitudes that exceed prespecified thresholds, and rates of change of voltages that exceed prespecified thresholds.

18. The method of claim 15, wherein the at least one parameter includes at least one of carrier signal frequency, carrier signal phase, code frequency, and code phase.

19. The method of claim 15, further comprising maintaining at least one local time reference signal during the at least one event, the local time reference signal related to a time base of a transmitter of the received signal.

20. The method of claim 15, wherein controlling at least one of receipt and processing includes receiving a first segment and a second segment of the signal, wherein the signal includes at least one of noise and pseudo-noise and the first and second segments represent samples of the signal during first and second periods of time.

21. The method of claim 15, further comprising generating at least one hypothesis, wherein the correlation analyses includes generating first correlation data representative of a correlation between at least one first segment of the signal and the hypothesis, and second correlation data representative of a correlation between at least one second segment of the signal and the hypothesis.

22. The method of claim 15, further comprising determining a parameter difference between correlation data of the correlation analyses and adjusting selected correlation data responsive to the parameter difference, wherein generating cumulative correlation data comprises combining the adjusted correlation data with the correlation data.

23. The method of claim 15, wherein generating cumulative correlation data includes adjusting selected correlation data of the correlation analyses by shifting the selected correlation data in response to a difference in the at least one parameter.

24. The method of claim 15, wherein the received signal is a Global Positioning System (GPS) signal.

25. A cellular telephone, comprising:

a voice communications system;

a Global Positioning System (GPS) receiver that receives GPS signals; and

at least one signal processing system coupled among the voice communications system and the GPS receiver, the signal processing system configured to perform at least one of detecting and tracking GPS signals, wherein at least one of the GPS receiver and the signal processing system receive and process the GPS signals in response to a state of a control signal that is generated in response to at least one event, wherein the signal processing system correlates multiple segments of the GPS signals from separate and distinct periods of time, generates cumulative correlation data by combining selected results of the correlations, and maintains at least one parameter of the GPS signals across a time period of the at least one event using the cumulative correlation data.

26. Computer readable media including instructions which, when executed in a processing system, perform at least one of detecting and tracking signals, by:

receiving a control signal that is generated in response to at least one event;

controlling at least one of receipt and processing of at least one signal in response to a state of the control signal;

performing correlation analyses of multiple segments of the received signal from separate and distinct periods of time;

generating cumulative correlation data by combining selected results of the correlation analyses; and

maintaining at least one parameter of the at least one received signal across a time period of the at least one event using the cumulative correlation data.