SYNTHETIC APERTURE FOR LOCATING MOBILE TRANSMITTERS

• US 20080161016A1
• Filed: 12/28/2006
• Published: 07/03/2008
• Est. Priority Date: 12/28/2006
• Status: Abandoned Application

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Marzetta, Thomas L., Hochwald, Bertrand M., Romain, Dennis M.
• Application Number:
  US11/617,643
• Publication Number:
  US 20080161016A1
• Time in Patent Office: Days
• US Class Current: 455/456.2
• CPC Class Codes: G01S 13/904 SAR modes
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting

Abstract

The present invention provides a module for locating a mobile device. In one embodiment, the module is configured to determine a location of a mobile device based on phase-sensitive measurements of wireless signals transmitted by the mobile device. Correspondingly, the module is configured to determine the location based on the phase-sensitive measurements of the wireless signals made at multiple measurement sites.

Claims

1. An apparatus, comprising:

a module configured to determine a location of a mobile device based on phase-sensitive measurements of wireless signals transmitted by the mobile device; and

wherein the module is configured to determine the location based on the phase-sensitive measurements of the wireless signals made at multiple measurement sites.

2. The apparatus of claim 1, wherein the module includes an interface configured to provide location data corresponding to multiple measurement sites created by an orbiting aircraft.

3. The apparatus of claim 2, wherein the location data provided by the interface corresponds to the module maintaining a substantially circular trajectory around the mobile device.

4. The apparatus of claim 2, wherein the location data provided by the interface corresponds to the module maintaining a substantially constant altitude over the mobile device.

5. The apparatus of claim 2, wherein the location data provided by the interface corresponds to maintaining a substantially constant speed of the module.

6. The apparatus of claim 1, wherein the module includes a directional antenna configured to provide a data signal proportional to the wireless signals transmitted by the mobile device.

7. The apparatus of claim 6 wherein the directional antenna employs orthogonal antenna elements oriented for reception of the wireless signals.

8. The apparatus of claim 7 wherein the orthogonal antenna elements employ half-wavelength spacing.

9. The apparatus of claim 1 wherein the module is configured to use a synthetic aperture geo-location technique employing the phase-sensitive measurements of the wireless signals to reduce an error in a geo-location of the mobile device below a predetermined value.

10. The apparatus of claim 9 wherein the module is configured to employ multiple measurement sites corresponding to regularly-spaced measurement intervals.

11. A method, comprising:

receiving a wireless signal from a mobile transmitter at a sequence of locations of a receiver;

determining one or more phase-dependent characteristics of the wireless signal, the one or more characteristics depending on relative locations of the receiver and the mobile transmitter; and

finding a geo-location of the mobile transmitter from the determined one or more phase-dependent characteristics.

12. The method of claim 11, wherein receiving the wireless signal employs a directional reception of the wireless signal.

13. The method of claim 12 wherein the directional reception employs orthogonal reception components.

14. The method of claim 13, wherein the orthogonal reception components are derived from antenna elements that employ half-wavelength spacing.

15. The method of claim 11, wherein determining one or more phase-dependent characteristics employs location data corresponding to multiple measurement sites of the receiver.

16. The method of claim 15, wherein the multiple measurement sites correspond to the receiver maintaining a substantially circular trajectory around the mobile transmitter.

17. The method of claim 15, wherein the multiple measurement sites correspond to the receiver maintaining a substantially constant altitude over the mobile transmitter.

18. The method of claim 15, wherein the multiple measurement sites correspond to the receiver maintaining a substantially constant speed.

19. The method of claim 11 wherein finding the geo-location of the mobile transmitter employs a synthetic aperture geo-location technique using the one or more phase-dependent characteristics.

20. The method of claim 19 wherein the synthetic aperture geo-location technique employs regularly-spaced measurement intervals.

21. The method of claim 20, wherein the regularly-spaced measurement intervals correspond to at least four locations on a substantially circular trajectory of the receiver.

22. The method of claim 21, wherein the at least four locations occur over at least one half the length of the substantially circular trajectory.