SYSTEMS AND METHODS OF WIRELESS POSITION TRACKING

• US 20140300516A1
• Filed: 11/13/2012
• Published: 10/09/2014
• Est. Priority Date: 11/10/2011
• Status: Active Grant

• Current Assignee: Position Imaging, Inc.
• Original Assignee: Position Imaging, Inc.
• Inventors: Schneider, Mark, Min, Guohua
• Granted Patent: US 9,945,940 B2
• Time in Patent Office: Days
• US Class Current: 342/450
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: G01S 5/08 Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

Position and orientation tracking systems and methods include a transmitting antenna transmitting a radio frequency (RF) signal. At least one receiving antenna acquires the RF signal. One of the at least one receiving antenna and the transmitting antenna is designated a reference antenna. A processing unit determines a phase difference between the RF signal received by each receiving antenna and the reference antenna. The processing unit computes a position of the transmitting antenna with respect to the at least one receiving antenna in response to the phase difference determined for each receiving antenna.

Claims

1. A position tracking system comprising,

a radio frequency (RF) transmitter transmitting an RF signal;

an RF receiver in communication with the RF transmitter to receive the RF signal;

a controller in communication with the RF receiver to receive the RF signal and to perform a time of flight estimation of the RF signal from the transmitter to receiver and to measure phase shift for sub-wavelength determination; and

a computing system in communication with the controller to receive the time of flight estimation and measured phase shift and to determine a position of the RF transmitter with respect to the RF receiver in response to the time of flight estimation and measured phase shift.

2. The position tracking system of claim 1, wherein the RF transmitter transmits a modulated carrier signal.

3. The position tracking system of claim 2, wherein a carrier wavelength of the RF transmitter is suitable for sub-wavelength phase measurement.

4. The position tracking system of claim 2, wherein the RF receiver demodulates the modulated carrier signal from the RF transmitter.

5. The position tracking system of claim 1, wherein the controller is in communication with the RF transmitter to receive a reference signal therefrom, and wherein the time of flight estimation includes a correlation-type process between a reference signal from the RF transmitter that is received at the receiver and compared with the reference signal sent from the RF transmitter and received by the controller.

6. The position tracking system of claim 1, wherein the phase shift measurement is determined by calculating in-phase and out-of-phase components of the carrier signal after demodulation at the RF receiver.

7. The position tracking system of claim 1, wherein the computing system receives time delay information determined by the time of flight estimation and the phase shift determined from in-phase and out-of-phase components of the carrier signal and determines a time of flight between the RF transmitter and the RF receiver.

8. The position tracking system of claim 1, further comprising a plurality of receiver antennae for determining multiple location and orientation parameters of the RF transmitter.

9. The position tracking system of claim 8, wherein the plurality of RF receiver antennae includes at least three receiver antennae for determining three location parameters of the RF transmitter.

10. The position tracking system of claim 8, further comprising a plurality of RF transmitters in communication with the plurality of RF receivers.

11. A position tracking system, comprising:

a transmitting antenna transmitting a radio frequency (RF) signal;

at least one receiving antenna acquiring the RF signal, one of the at least one receiving antenna and the transmitting antenna being designated a reference antenna;

a processing unit determining a phase difference between the RF signal received by each receiving antenna and the reference antenna, the processing unit computing a position of the transmitting antenna with respect to the at least one receiving antenna in response to the phase difference determined for each receiving antenna.

12. The position tracking system of claim 11, wherein one of the at least one receiver antennae is the designated reference antenna.

13. The position tracking system of claim 11, wherein the designated reference antenna is dynamically re-assignable among the receiving antennae.

14. The position tracking system of claim 11, wherein the transmitting antenna is the designated reference antenna.

15. The position tracking system of claim 11, wherein a wavelength of the RF signal transmitted by the transmitting antenna is smaller than a tracking volume.

16. The position tracking system of claim 11, wherein the processing unit applies a filter to unwrap phase for each determined phase difference.

17. The position tracking system of claim 11, wherein the processing unit determines a solution for the position of the transmitting antenna, uses the solution to calculate an expected phase difference for each receiving antenna, and uses the calculated expected phase difference for a given receiving antenna when the given receiving antenna loses the transmitted RF signal.

18. The position tracking system of claim 11, wherein the at least one receiving antenna includes at least three receiving antennae disposed at known locations for two-dimensional position detection of the transmitting antenna.

19. The position tracking system of claim 11, wherein the at least one receiving antenna includes at least four receiving antennae disposed at known locations for three-dimensional position detection of the transmitting antenna, wherein one of the receiving antennae is the designated reference antenna.

20. The position tracking system of claim 11, further comprising at least two other transmitting antennae disposed at known positions.

21. The position tracking system of claim 11, wherein the RF signal carries an identifier associated with the transmitting antenna, the identifier corresponding to a code generated from a specific sequence of frequency hops or similar wireless coding techniques.

22. A method of tracking position of a transmitting antenna, comprising:

receiving a radio frequency (RF) signal, transmitted by the transmitting antenna, by at least one receiving antenna;

designating one of the antennae as a reference antenna;

determining a phase difference between the RF signal received by each receiving antenna and the reference antenna; and

computing a position of the transmitting antenna with respect to the at least one receiving antenna in response to each phase difference determined for each receiving antenna.

23. The method of claim 22, wherein the transmitting antenna is the designated reference antenna.

24. The method of claim 22, wherein the at least one receiving antenna includes at least three receiving antennae for two-dimensional transmitter tracking or four receiving antennae for three dimensional transmitter tracking and uses one of the multiple receiving antennae as the designated reference antenna.

25. The method of claim 24, further comprising dynamically reassigning the designation of the reference antenna from the given one of the at least four receiving antennae to another of the at least four receiving antennae.

26. The method of claim 22, further comprising applying a filter to unwrap phase for each determined phase difference.

27. The method of claim 22, further comprising determining a solution for position of the transmitting antenna, calculating an expected phase difference for each receiving antenna based on the solution and previous phase data, and using the expected phase difference calculated for a given receiving antenna when the given receiving antenna loses the transmitted RF signal.

28. The method of claim 22, further comprising generating an identifier associated with the transmitting antenna by generating a code from a specific sequence of frequency hops.

29. A method of tracking position comprising,

receiving a radio frequency (RF) signal, transmitted by a transmitting antenna, by three or more receiving antennae;

performing a time of flight estimation of the RF signal from the transmitting antenna to the receiving antennae;

measuring phase shift between the transmitted RF signal and the received RF signal at each receiving antenna; and

determining a position of the transmitting antenna with respect to the receiving antennae in response to the time of flight estimation and the measured phase shift at each receiving antenna.

30. The method of claim 29, wherein performing a time of flight estimation of the RF signal to the receiving antennae includes comparing a code reference signal with a code sequence that is synchronized with the RF signal.

31. The method of claim 29, wherein measuring phase shift between the transmitted RF signal and the received RF signal at each receiving antenna includes using a reference carrier signal to determine in-phase and out-of-phase components of the RF signal.