METHOD AND SYSTEM FOR ESTIMATION OF MOBILE STATION VELOCITY IN A CELLULAR SYSTEM BASED ON GEOGRAPHICAL DATA

• US 20110287778A1
• Filed: 05/16/2011
• Published: 11/24/2011
• Est. Priority Date: 05/24/2010
• Status: Active Grant

• Current Assignee: Cyberbit Ltd.
• Original Assignee: Nice Systems Limited (Nice Ltd)
• Inventors: Levin, Moshe, Freedman, Avraham
• Granted Patent: US 8,588,808 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 11/026 using moving transmitters
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A system and method for estimating velocity of a mobile station in a wireless communication system using time-frequency signal processing and a geographical database. The geographical database is used for prediction of ray trajectory and ray power to provide an estimate of propagation delay associated with database points.

Claims

1. A method of estimating velocity of a mobile station comprising:

receiving a signal from a mobile terminal;

determining a Doppler shift of said received signal; and

processing said signal using time-frequency signal processing and a geographical database to determine a velocity estimate.

2. The method of claim 1, wherein said processing further comprises analyzing said received signal using ray tracing.

3. The method of claim 2, wherein said processing further comprises using said time-frequency analysis to resolve said received signal into components and identifying scatterers and scatterers'"'"' contributions to said components.

4. The method of claim 3, wherein said processing further comprises identifying corresponding said scatterers and said rays, and calculating Doppler estimates of said corresponding scatterers and rays.

5. The method of claim 4, wherein said time-frequency signal processing further comprises determining a delay of said Doppler shift, and using matched filtering of said received signal and said delayed Doppler shifted signal.

6. The method of claim 5, wherein said delayed Doppler shifted signal is used to locate said scatterers on a map.

7. The method of claim 6, wherein said map is a delay-Doppler map.

8. The method of claim 5, wherein said Doppler shift is determined from a range gate.

9. The method of claim 8, further comprising determining a profile from said matched filtering, computing local maxima of a said profile to determine a partial model, and determining said estimation using said partial model.

10. The method of claim 8, further comprising using said Doppler shift determined from said range gate to determine clusters, and using at least said clusters to determine said estimate.

11. The method of claim 8, further comprising using ray tracing to further identify scatterers by calculating a Doppler spectra from said time-frequency analysis, determining one or more biases from said Doppler estimate, and calculating a best fit of said biases to said Doppler spectra.

12. The method of claim 11, wherein said best fit calculation includes a multidimensional search.

13. The method of claim 11, wherein said Doppler estimation for each said range gate is determined using a weighted least square estimator, where said weighted least square estimator further comprises computing velocity and direction of each said scatterer in each said range gate, estimating amplitude, phase and bias, estimating a standard deviation of errors of said amplitude, phase and bias estimates, using said standard deviation estimate to calculate said weighted least square estimate.

14. The method of claim 13, wherein said standard deviation estimate is calculated using ray tracing analysis.

15. The method of claim 13, wherein said standard deviation analysis is calculated using a profile of said Doppler spectra.

16. The method of claim 1, wherein said velocity estimate is in terms of magnitude and direction.

17. The method of claim 1, wherein said determining said Doppler shift further comprises determining a Doppler spread pattern.

18. The method of claim 17, wherein said processing further comprises using a predicted delay profile.

19. The method of claim 1, wherein said received signal from said mobile terminal is sent using an antenna array.

20. The method of claim 1, wherein said signal is received at a plurality of receivers to form a plurality of received signals, the location of each of said receivers is correlated to each said plurality of received signals, and said correlated received signals and said receiver locations are used in said processing.

21. A method for enhanced location estimation comprising:

receiving a signal from a mobile terminal;

determining a Doppler shift of said received signal;

processing said signal using time-frequency signal processing and a geographical database to determine a velocity estimate;

integrating said velocity estimate and location measurement data; and

calculating an enhanced location estimate using said integration.

22. The method of claim 21, wherein said integration further comprises filtering.

23. A system for estimating velocity of a mobile station comprising:

a mobile station capable of transmitting signals;

a fixed station capable of receiving signals transmitted by at least said mobile station;

a geographical database;

a processor operably connected to said fixed station and said geographical database, to process a signal sent from said mobile station to said fixed station with data from said geographical database to determine an estimate of velocity of said mobile station.

24. The system of claim 23, wherein said mobile station further comprises an antenna.

25. The system of claim 24, wherein said antenna is an antenna array.

26. The system of claim 23, wherein said fixed station further comprises a receiver and an antenna.

27. The system of claim 26, wherein said antenna is an antenna array.

28. The system of claim 23, wherein said geographical database is located within said fixed station.

29. The system of claim 23, wherein said processor is located within said fixed station.

30. The system of claim 23, further comprising a plurality of said fixed stations, and said processor to process said signals received by said plurality of fixed stations.

31. The system of claim 23, wherein said processor further processes said signal using time-frequency signal processing.

32. The system of claim 31, wherein said processor further processes said signal using ray tracing.

33. The system of claim 32, wherein said processor further processes said signal to resolve said signal into component parts and identify scatterers and scatterers'"'"' contributions to said components.

34. The system of claim 33, wherein said processor further processes said signal to calculate Doppler estimates of rays corresponding to scatterers.

35. The system of claim 34, wherein said processor further processes said signal using matched filtering of said Doppler estimate and of a shifted Doppler estimate.

36. The system of claim 35, wherein said processor further uses said delayed Doppler estimate and said geographical database to locate scatterers on a map.

37. The system of claim 35, wherein said processor determines said shifted Doppler estimate using a range gate.

38. The system of claim 37, wherein said processor further processes said signal to calculate a best fit of biases to a Doppler spectra, where said Doppler spectra is calculated from said time-frequency analysis using said ray tracing to identify said scatterers, and where said biases are calculated from said Doppler estimate.

39. The system of claim 37, wherein said processor further processes said signal to determine a weighted least squares estimator, where said weighted least squares estimator is calculated from the velocity and direction of each said scatterer in each said range gate, an estimate of amplitude, phase and bias, and an estimate of standard deviation of errors of said amplitude, phase and bias.

40. The system of claim 23, wherein said velocity estimate further comprises magnitude and direction.

41. The system of claim 23, wherein said processor further processes said signal using a predicted delay profile and a Doppler spread pattern, where said Doppler spread pattern is calculated from a Doppler shift of said signal.