Systems and methods of wireless position tracking

• US 9,945,940 B2
• Filed: 11/13/2012
• Issued: 04/17/2018
• Est. Priority Date: 11/10/2011
• Status: Active Grant

• Current Assignee: Position Imaging, Inc.
• Original Assignee: Position Imaging, Inc.
• Inventors: Min, Guohua, Schneider, Mark
• Primary Examiner(s): Phan, Dao L
• Application Number:
  US14/354,833
• Publication Number:
  US 20140300516A1
• Time in Patent Office: 1,981 Days
• Field of Search: 342442, 342450, 342457, 342463-465, 455457, 4554561
• 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 a pseudo-noise code modulated RF signal;

an RF receiver in communication with the RF transmitter to receive and demodulate the pseudo-noise code modulated RF signal;

a controller in communication with the RF receiver to receive the pseudo-noise code modulated RF signal, the controller including a reference generator to provide a code reference signal that is synchronized with the pseudo-noise code modulated RF signal, a code discriminator to perform a time of flight estimation of the RF signal from the transmitter to receiver by comparing the code reference signal with a recovered signal derived from the pseudo-noise code modulated RF signal, and a carrier phase discriminator 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 based on a combination of the time of flight estimation and measured phase shift.

2. The position tracking system of claim 1, wherein a carrier wavelength of the RF transmitter is suitable for sub-wavelength phase measurement.

3. The position tracking system of claim 1, wherein the reference signal generator is in communication with the RF transmitter to receive a reference signal therefrom, the reference signal generator providing the code reference signal based on the reference signal received from the RF transmitter, and wherein in performing the time of flight estimation the code discriminator performs a correlation-type process between the code reference signal and the recovered signal derived from the pseudo-noise code modulated RF signal, the recovered signal being a pseudo-noise code sequence.

4. The position tracking system of claim 1, wherein the carrier phase discriminator determines the phase shift measurement by integrating in-phase and out-of-phase components of the demodulated pseudo-noise code modulated RF signal and determining the phase shift based on a ratio of the demodulated integrated in-phase and out-of-phase components of the pseudo-noise code modulated RF signal.

5. The position tracking system of claim 4, wherein the computing system receives time delay information determined by the time of flight estimation and the measured phase shift and determines a time of flight between the RF transmitter and the RF receiver.

6. 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.

7. The position tracking system of claim 6, wherein the plurality of RF receiver antennae includes at least three receiver antennae for determining three location parameters of the RF transmitter.

8. The position tracking system of claim 6, further comprising a plurality of RF transmitters in communication with the plurality of RF receivers to provide orientation information.

14. The position tracking system of claim 6, wherein the RF transmitter is associated with an object, the position tracking system being configured to track a position of the object and further comprising a plurality of additional RF transmitters associated with the object and in communication with the plurality of RF receivers to provide at least three pseudo-noise code modulated RF signals to provide three-dimensional orientation information of the object.

9. A method of tracking position comprising,

receiving a pseudo-noise code modulated 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 based on a comparison between a recovered signal derived from the pseudo-noise code modulated RF signal and a reference pseudo-noise code modulated signal that is synchronized with the RF signal;

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 based on a combination of the time of flight estimation and the measured phase shift at each receiving antenna.

10. The method of claim 9, wherein measuring phase shift between the transmitted RF signal and the received RF signal at each receiving antenna includes demodulating in-phase and out-of-phase components of the RF signal using a reference carrier signal.

11. The method of claim 10, wherein measuring the phase shift further includes integrating the demodulated in-phase and out-of-phase components of the received RF signal at each receiving antenna and determining a ratio of the demodulated integrated in-phase and out-of-phase components of the RF signal.

12. The method of claim 9, further comprising determining multiple location and orientation parameters of the transmitting antenna.

13. The method of claim 9, further comprising determining three location parameters of the transmitting antenna.