System and method of locating a radio frequency (RF) tracking device using a calibration routine

• US 10,237,698 B2
• Filed: 08/25/2016
• Issued: 03/19/2019
• Est. Priority Date: 01/18/2013
• Status: Active Grant

• Current Assignee: Position Imaging, Inc.
• Original Assignee: Position Imaging, Inc.
• Inventors: Min, Guohua, Hill, Edward L.
• Primary Examiner(s): Liu, Harry K
• Application Number:
  US15/246,783
• Publication Number:
  US 20160366561A1
• Time in Patent Office: 936 Days
• Field of Search: 342465
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

Position tracking systems and methods for tracking a physical location of a radio frequency (RF) transmitter include an RF transmitter transmitting an RF signal from a plurality of known locations. At least four RF receiver antennae are disposed at unknown locations within range of the RF transmitter to receive the RF signals transmitted from the plurality of known locations. A receiver station in communication with the at least four RF receiver antennae initially calibrates a relative position of each RF receiver antenna with respect to the other RF receiver antennae based on the plurality of known locations and on information acquired in response to the RF signals received at the at least four RF receiver antennae.

Claims

1. A calibration system for calibrating a position tracking system used to track a physical location of a radio frequency (RF) transmitter, the calibration system comprising:

an RF transmitter transmitting an RF signal from each of a plurality of locations where the RF transmitter is placed in successive order;

at least four RF receiver antennae disposed at undetermined locations within range of the RF transmitter to receive the RF signals transmitted from the plurality of locations;

a calibration apparatus configured to provide a calibration template with a predetermined set of reference points, each reference point corresponding to one of the plurality of locations where the RF transmitter is placed in successive order and from which the RF transmitter transmits the RF signal; and

a receiver station in communication with the at least four RF receiver antennae, the receiver station being configured to know where each reference point is located on the calibration template, the receiver station initially calibrating a relative position of each RF receiver antenna with respect to each other RF receiver antenna based on the plurality of locations and on information acquired in response to the RF signals received at the at least four RF receiver antennae.

2. The calibration system of claim 1, wherein the receiver station comprises:

a controller unit computing time difference of arrival measurements for the RF signal transmitted from each of the plurality of locations and received at each of the at least four RF receiver antennae; and

a computing system determining the relative position of each RF receiver antenna with respect to each other RF receiver antennae based on the computed time difference of arrival measurements and on the plurality of locations.

3. The calibration system of claim 1, wherein the receiver station comprises the calibration apparatus that is configured to provide the calibration template with the predetermined set of reference points.

4. The calibration system of claim 1, wherein the receiver station refers to a known three-dimensional model of the calibration template when the RF transmitter is placed at each reference point of the calibration template.

5. The calibration system of claim 1, wherein the plurality of locations are all on a same plane.

6. The calibration system of claim 1, wherein a distance between each of the RF receiver antennae and each of the other RF receiver antennae is fixed.

7. The calibration system of claim 1, wherein the receiver station is configured to compute dynamically a position of an RF-transmitting device based on the calibrated relative positions of the RF receiver antennae after initial calibration.

8. The calibration system of claim 1, wherein the calibration apparatus is part of equipment separate from the receiver station.

9. A method for calibrating a position tracking system used to track a physical location of a radio frequency (RF) transmitter, the method comprising:

receiving, by at least four RF receiver antennae disposed at undetermined locations, an RF signal transmitted from each of a plurality of locations in successive order by an RF transmitter;

positioning a calibration template with a predetermined set of reference points at known locations relative to a given reference point such that each reference point of the predetermined set corresponds to one of the plurality of locations from which the RF transmitter transmits the RF signal; and

calibrating a relative position of each RF receiver antenna with respect to each other RF receiver antenna based on the plurality of locations and information acquired in response to the RF signals received at the at least four RF receiver antennae.

10. The method of claim 9, wherein calibrating a relative position of each RF receiver antenna with respect to the other RF receiver antennae includes:

computing time difference of arrival measurements for the RF signal transmitted from each of the plurality of locations and received at each of the at least four RF receiver antennae; and

computing the relative position of each RF receiver antenna with respect to the other RF receiver antennae based on the computed time difference of arrival measurements and on the plurality of locations.

11. The method of claim 9, further comprising referring to a known three-dimensional model of the calibration template when the RF transmitter is placed at each reference point of the calibration template.

12. The method of claim 9, wherein the plurality of locations are all on a same plane.

13. The method of claim 9, wherein a distance between each of the RF receiver antennae and each of the other RF receiver antennae is fixed.

14. The method of claim 9, further comprising dynamically computing the physical location of the RF-transmitting device based on the relative positions of the at least four RF receiver antennae after the calibrating of the relative position of each RF receiver antenna with respect to each other RF receiver antennae.

15. A calibration system for calibrating a position tracking system used to track a physical location of a radio frequency (RF)-transmitting tracked device, the position tracking system having at least four RF receiver antennae, the calibration system comprising:

a receiver station comprising;

a controller unit in communication with the at least four RF receiver antennae disposed at undetermined locations, the controller unit computing a set of timing measurements for each of at least four different transmissions of RF signals transmitted from at least four different locations in successive order by the RF-transmitting tracked device and received at each of the at least four RF receiver antennae;

a computing system in communication with the controller unit to receive therefrom the sets of timing measurements, the computing system including memory that stores a position location for each of the at least four different locations and associates each set of timing measurements with one of the at least four different locations, the computer system further comprising a processor configured to compute a relative position of each RF receiver antenna with respect to the other RF receiver antennae based on the at least four different locations and the sets of timing measurements; and

a calibration apparatus configured to provide a calibration template with a predetermined set of reference points, the calibration apparatus being disposed relative to the computing system such that each reference point is located at a different one of the position locations stored in the memory and corresponds to one of the one of the at least four different locations from which the RF-transmitting tracked device transmitted RF signals.

16. The calibration system of claim 15, wherein the memory stores a three-dimensional model of the calibration template.

17. The calibration system of claim 15, wherein the computing system is further configured to compute dynamically the physical location of the RF-transmitting tracked device based on the computed relative positions of the at least four RF receiver antennae after initial calibration.

18. The calibration system of claim 15, wherein the receiver station comprises the calibration apparatus that is configured to provide the calibration template with the predetermined set of reference points.

19. The calibration system of claim 15, wherein the RF-transmitting tracking device includes an RF transmitter and a processor configured to execute a calibration application that, when executed, guides a user to move the tracking device sequentially to each of the reference points and to activate the RF transmitter at that reference point.

20. The calibration system of claim 15, wherein the calibration apparatus is part of equipment separate from the receiver station.