Position tracking system and method using radio signals and inertial sensing

• US 8,957,812 B1
• Filed: 11/10/2011
• Issued: 02/17/2015
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Position Imaging, Inc.
• Original Assignee: Position Imaging, Inc.
• Inventors: Hill, Edward, Schneider, Mark
• Primary Examiner(s): Phan, Dao
• Application Number:
  US13/293,639
• Time in Patent Office: 1,195 Days
• Field of Search: 342/437, 342/445, 342/463, 342/465, 455/456.6, 455/457
• US Class Current: 342/465
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile
• CPC Class Codes: G01S 5/02585 at least one of the measurements being a non-radio measurement
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering

Abstract

An RF position tracking system for wirelessly tracking the three dimensional position of a device that transmits a radio signal. The device has an antenna and at least one inertial sensor. The system uses a plurality of receiver antennas to receive the device'"'"'s radio signal at each antenna. The device also incorporates an inertial sensor to improve position stability by allowing the system to compare position data from radio signals to data provided by the inertial sensor.

Claims

1. A method of an object having an inertial sensor and capable of transmitting a radio frequency (RF) signal, the method comprising:

each of at least three antennae receiving an RF signal emitted from the object;

receiving an inertial signal from the inertial sensor; and

processing the RF signal and the inertial signal to determine a position of the object, by applying a fusing algorithm to the received RF signal and the received inertial signal.

2. The method of claim 1, wherein the inertial sensor is selected from the group consisting of a gyroscope, an accelerometer, and a magnetic sensor.

3. The method of claim 1, further comprising the step of merging the received RF signal and the received inertial signal with a Kalman filter.

4. The method of claim 1, wherein the processing step comprises determining the position of the object in two dimensions.

5. The method of claim 1, wherein the processing step comprises determining the position of the object in three dimensions.

6. The method of claim 1, wherein the processing step comprises a first step of pre-processing the received RF signal and a second step of processing the inertial signal.

7. The method of claim 1, wherein the processing step comprises a simultaneous, tightly-coupled processing of both the received RF signal and the received inertial signal data.

8. A receiver for determining a position of an object being tracked, comprising:

at least three antennae configured to receive an RF signal from the object;

an inertial input configured to receive inertial position information from the object; and

a processor in communication with the at least three antennae and the inertial input, the processor receiving the RF signal and the inertial position information and determining the position of the object being tracked by applying a fusing algorithm to the received RF signal and the received inertial position information.

9. The receiver of claim 8, wherein the processor is configured to merge the received RF signal and the received inertial position information with a Kalman filter.

10. The receiver of claim 8, wherein the processor is configured to determine the position of the object in two dimensions.

11. The receiver of claim 8, wherein the processor is configured to determine the position of the object in three dimensions.

12. The receiver of claim 8, wherein the processor is configured to pre-process the received RF signal and processes the inertial position information.

13. The receiver of claim 8, wherein the processor is configured to perform a simultaneous, tightly-coupled processing of both the received RF signal and the received inertial position information.