Method and system for estimating a subscriber's location in a cluttered area

• US 6,148,211 A
• Filed: 09/05/1997
• Issued: 11/14/2000
• Est. Priority Date: 09/05/1997
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wang, Shu-Shaw (Peter), Reed, John Douglas
• Primary Examiner(s): MAUNG, NAY AUNG
• Application Number:
  US08/924,151
• Time in Patent Office: 1,166 Days
• Field of Search: 455/11.1, 455/67.6, 455/404, 455/422, 455/427, 455/456, 455/457, 342/357, 342/453, 342/457, 701/300
• US Class Current: 455/456.2
• CPC Class Codes: G01S 5/02528 Simulating radio frequency fingerprints
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

In a model of a wireless communication system service area (160), a set of characteristics associated with the reception of a model signal (210) are calculated (308), preferably using ray-tracing techniques, wherein the model signal (172) is transmitted from a selected location (162) to a receiver location (166). Next, a set of characteristics that describe a received signal at a receiver location in the wireless communication system service area are measured (316), wherein the receiver location corresponds to the receiver location in the model (160). Thereafter, a relationship between the calculated set of characteristics and the measured set of characteristics is determined (318), and the location of the subscriber unit that transmitted the received signal is estimated (320) in response to the relationship between the calculated set of characteristics and the measured set of characteristics.

Claims

1. A method for estimating a location of a subscriber unit in a wireless communication system service area, comprising the steps of:

calculating a set of characteristics associated with the reception of a model signal, wherein the model signal represents a signal transmitted from a selected location to a receiver location in a model that represents the wireless communication system service area;

measuring a set of characteristics that describe a received signal at a receiver location in the wireless communication system service area, wherein the receiver location in the wireless communication system service area corresponds to the receiver location in the model;

determining a relationship between the calculated set of characteristics and the measured set of characteristics; and

in response to the relationship between the calculated set of characteristics and the measured set of characteristics, estimating the location of the subscriber unit that transmitted the received signal.

2. The method for estimating a location according to claim 1 further including the step of adjusting the set of calculated characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

3. The method for estimating a location according to claim 1 further including the step of adjusting the relationship between the calculated set of characteristics and the measured set of characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

4. The method for estimating a location according to claim 1 wherein the step of calculating a set of characteristics associated with the reception of a model signal further includes the steps of:

estimating propagation paths using ray-tracing techniques; and

calculating a set of characteristics associated with the reception of a model signal in response to the estimated propagation paths.

5. The method for estimating a location according to claim 1 further including the steps of:

calculating a second set of characteristics associated with reception of a second model signal at a second receiver location in the model that represents the wireless communication system;

measuring a second set of characteristics that describe a second received signal at a second receiver location in the wireless communication system service area, wherein the second receiver location in the wireless communication system service area corresponds to the second receiver location in the model;

determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

in response to the relationship between each calculated set of characteristics and each measured set of characteristics, estimating the location of the subscriber unit that transmitted the signal received at each receiver location.

6. The method for estimating a location according to claim 1 further including the steps of:

calculating a set of characteristics associated with reception of a second model signal at the receiver location, wherein a path of the second model signal is different from a path of the model signal;

measuring a second set of characteristics that describe a second received signal at the receiver location in the wireless communication system, wherein a path of the second received signal is different from a path of the received signal;

determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

in response to the relationship between each calculated set of characteristics and each measured set of characteristics, estimating the location of the subscriber unit that transmitted the signal and the second signal.

7. The method for estimating a location according to claim 1 wherein the calculated set of characteristics and the measured set of characteristics each include an angle of arrival of the received signal.

8. The method for estimating a location according to claim 1 wherein the calculated set of characteristics and the measured set of characteristics each include a time of flight of the received signal.

9. The method for estimating a location according to claim 1 wherein the calculated set of characteristics and the measured set of characteristics each include a received signal strength of the received signal.

10. The method for estimating a location according to claim 5 wherein the calculated set of characteristics and the measured set of characteristics each include a difference between time of flight at the receiver location and time of flight at the second receiver location.

12. The system for estimating a location according to claim 10 further including means for adjusting the set of calculated characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

13. The system for estimating a location according to claim 10 further including means for adjusting the relationship between the calculated set of characteristics and the measured set of characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

14. The system for estimating a location according to claim 10 wherein the means for calculating a set of characteristics associated with the reception of a model signal further includes:

means for estimating propagation paths using ray-tracing techniques; and

means for calculating a set of characteristics associated with the reception of a model signal in response to the estimated propagation paths.

15. The system for estimating a location according to claim 10 further including:

means for calculating a second set of characteristics associated with reception of a second model signal at a second receiver location in the model that represents the wireless communication system;

means for measuring a second set of characteristics that describe a second received signal at a second receiver location in the wireless communication system service area, wherein the second receiver location in the wireless communication system service area corresponds to the second receiver location in the model;

means for determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

means for estimating the location of the subscriber unit that transmitted the signal received at each receiver location responsive to the relationship between each calculated set of characteristics and each measured set of characteristics.

16. The system for estimating a location according to claim 10 further including:

means for calculating a set of characteristics associated with reception of a second model signal at the receiver location, wherein a path of the second model signal is different from a path of the model signal;

means for measuring a second set of characteristics that describe a second received signal at the receiver location in the wireless communication system, wherein a path of the second received signal is different from a path of the received signal;

means for determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

means for estimating the location of the subscriber unit that transmitted the signal and the second signal responsive to the relationship between each calculated set of characteristics and each measured set of characteristics.

17. The system for estimating a location according to claim 10 wherein the calculated set of characteristics and the measured set of characteristics each include an angle of arrival of the received signal.

18. The system for estimating a location according to claim 10 wherein the calculated set of characteristics and the measured set of characteristics each include a time of flight of the received signal.

19. The system for estimating a location according to claim 10 wherein the calculated set of characteristics and the measured set of characteristics each include a received signal strength of the received signal.

20. The system for estimating a location according to claim 15 wherein the calculated set of characteristics and the measured set of characteristics each include a difference between time of flight at the receiver location and time of flight at the second receiver location.

11. A system for estimating a location of a subscriber unit in a wireless communication system service area comprising:

means for calculating a set of characteristics associated with the reception of a model signal, wherein the model signal represents a signal transmitted from a selected location to a receiver location in a model that represents the wireless communication system service area;

means for measuring a set of characteristics that describe a received signal at a receiver location in the wireless communication system service area, wherein the receiver location in the wireless communication system service area corresponds to the receiver location in the model;

means for determining a relationship between the calculated set of characteristics and the measured set of characteristics; and

means for estimating the location of the subscriber unit that transmitted the received signal responsive to the relationship between the calculated set of characteristics and the measured set of characteristics.

21. A computer program product for estimating a location of a subscriber unit in a wireless communication system service area comprising:

a computer usable medium having computer readable program code means for calculating a set of characteristics associated with the reception of a model signal, wherein the model signal represents a signal transmitted from a selected location to a receiver location in a model that represents the wireless communication system service area;

a computer usable medium having computer readable program code means for measuring a set of characteristics that describe a received signal at a receiver location in the wireless communication system service area, wherein the receiver location in the wireless communication system service area corresponds to the receiver location in the model;

a computer usable medium having computer readable program code means for determining a relationship between the calculated set of characteristics and the measured set of characteristics; and

a computer usable medium having computer readable program code means for estimating the location of the subscriber unit that transmitted the received signal responsive to the relationship between the calculated set of characteristics and the measured set of characteristics.

22. The computer program product for estimating a location according to claim 21 further including a computer usable medium having computer readable program code means for adjusting the set of calculated characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

23. The computer program product for estimating a location according to claim 21 further including a computer usable medium having computer readable program code means for adjusting the relationship between the calculated set of characteristics and the measured set of characteristics in response to measuring a set of signal characteristics of a received signal transmitted from a known location in the wireless communication system service area.

24. The computer program product for estimating a location according to claim 21 wherein the computer usable medium having computer readable program code means for calculating a set of characteristics associated with the reception of a model signal further includes:

a computer usable medium having computer readable program code means for estimating propagation paths using ray-tracing techniques; and

a computer usable medium having computer readable program code means for calculating a set of characteristics associated with the reception of a model signal in response to the estimated propagation paths.

25. The computer program product for estimating a location according to claim 21 further including:

a computer usable medium having computer readable program code means for calculating a second set of characteristics associated with reception of a second model signal at a second receiver location in the model that represents the wireless communication system;

a computer usable medium having computer readable program code means for measuring a second set of characteristics that describe a second received signal at a second receiver location in the wireless communication system service area, wherein the second receiver location in the wireless communication system service area corresponds to the second receiver location in the model;

a computer usable medium having computer readable program code means for determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

a computer usable medium having computer readable program code means for estimating the location of the subscriber unit that transmitted the signal received at each receiver location responsive to the relationship between each calculated set of characteristics and each measured set of characteristics.

26. The computer program product for estimating a location according to claim 21 further including:

a computer usable medium having computer readable program code means for calculating a set of characteristics associated with reception of a second model signal at the receiver location, wherein a path of the second model signal is different from a path of the model signal;

a computer usable medium having computer readable program code means for measuring a second set of characteristics that describe a second received signal at the receiver location in the wireless communication system, wherein a path of the second received signal is different from a path of the received signal;

a computer usable medium having computer readable program code means for determining a relationship between each calculated set of characteristics and each measured set of characteristics; and

a computer usable medium having computer readable program code means for estimating the location of the subscriber unit that transmitted the signal and the second signal responsive to the relationship between each calculated set of characteristics and each measured set of characteristics.

27. The computer program product for estimating a location according to claim 21 wherein the calculated set of characteristics and the measured set of characteristics each include an angle of arrival of the received signal.

28. The computer program product for estimating a location according to claim 21 wherein the calculated set of characteristics and the measured set of characteristics each include a time of flight of the received signal.

29. The computer program product for estimating a location according to claim 21 wherein the calculated set of characteristics and the measured set of characteristics each include a received signal strength of the received signal.

30. The computer program product for estimating a location according to claim 25 wherein the calculated set of characteristics and the measured set of characteristics each include a difference between time of flight at the receiver location and time of flight at the second receiver location.