Baseline selection method for use in a wireless location system

• US 20020101375A1
• Filed: 12/05/2001
• Published: 08/01/2002
• Est. Priority Date: 01/08/1999
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.), Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Harbison, Andrew F., Anderson, Robert J., Sheehan, Joseph W., Stilp, Louis A., Rogers, Alan E. E.
• Granted Patent: US 6,483,460 B2
• Time in Patent Office: Days
• US Class Current: 342/465
• CPC Class Codes: G01S 1/026 of associated receivers
• CPC Class Codes: G01S 2205/006 for emergency situations
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 2205/06 Emergency
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0215 Interference
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/02216 Timing or synchronisation of the receivers
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/0246 involving frequency difference of arrival or Doppler measurements G01S5/02685 takes precedence
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0268 by deriving positions from different combinations of signals or of estimated positions in a single positioning system
• CPC Class Codes: G01S 5/0284 Relative positioning
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 76/50 for emergency connections
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A Wireless Location System includes signal collection systems and location processors for processing digital data provided by the signal collection systems. To determine the geographic location of a mobile wireless transmitter, time difference of arrival, or TDOA, data is determined with respect to a plurality of first signal collection system/antenna-second signal collection system/antenna baselines. A method for selecting baselines for use in location processing comprises calculating a number of parameters for each of the plurality of baselines, and including in a final location solution only those baselines meeting or exceeding predefined threshold criteria for each of the parameters.

Claims

1. A method for use in a wireless location system to determine the geographic location of a mobile wireless transmitter, the method comprising:

calculating a number of parameters for each of the plurality of baselines; and

including in a final location solution only those baselines meeting or exceeding predefined threshold criteria for each of the parameters.

2. A method as recited in claim 1, wherein the wireless location system includes signal collection systems and at least one location processor for processing digital data provided by the signal collection systems, wherein TDOA data is determined with respect to a plurality of first signal collection system/antenna-second signal collection system/antenna baselines.

3. A method as recited in claim 2, wherein the parameters include the average power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing.

4. A method as recited in claim 2, wherein the parameters include the peak power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing.

5. A method as recited in claim 2, wherein the parameters include the variance in the power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing

6. A method as recited in claim 2, wherein the parameters include the correlation value from a cross-spectra correlation between the second signal collection system/antenna used in the baseline and a first signal collection system/antenna.

7. A method as recited in claim 2, wherein the parameters include the delay value for the baseline.

8. A method as recited in claim 2, wherein the parameters include multipath mitigation parameters.

9. A method as recited in claim 2, wherein the parameters include residual values remaining after multipath mitigation calculations.

10. A method as recited in claim 2, wherein the parameters include a contribution of the second signal collection system/antenna to a weighted geometric dilution of precision in the final location solution.

11. A method as recited in claim 2, wherein the parameters include a measure of the quality of fit of the baseline in the final location solution, if the baseline were included.

13. An apparatus as recited in claim 12, wherein the wireless location system includes signal collection systems and at least one location processor for processing digital data provided by the signal collection systems, wherein TDOA data is determined with respect to a plurality of first signal collection system/antenna-second signal collection system/antenna baselines.

14. An apparatus as recited in claim 13, wherein the parameters include the average power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing.

15. An apparatus as recited in claim 13, wherein the parameters include the peak power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing.

16. An apparatus as recited in claim 13, wherein the parameters include the variance in the power of the transmission as received at the second signal collection system/antenna port used in a baseline and over an interval used for location processing

17. An apparatus as recited in claim 13, wherein the parameters include the correlation value from a cross-spectra correlation between the second signal collection system/antenna used in the baseline and a first signal collection system/antenna.

18. An apparatus as recited in claim 13, wherein the parameters include the delay value for the baseline.

19. An apparatus as recited in claim 13, wherein the parameters include multipath mitigation parameters.

20. An apparatus as recited in claim 13, wherein the parameters include residual values remaining after multipath mitigation calculations.

21. An apparatus as recited in claim 13, wherein the parameters include a contribution of the second signal collection system/antenna to a weighted geometric dilution of precision in the final location solution.

22. An apparatus as recited in claim 13, wherein the parameters include a measure of the quality of fit of the baseline in the final location solution, if the baseline were included.

12. An apparatus for use in wireless location system to determine the geographic location of a mobile wireless transmitter, comprising:

means for calculating a number of parameters for each of the plurality of baselines; and

means for including in a final location solution only those baselines meeting or exceeding predefined threshold criteria for each of the parameters.