System and method for range and angle determination to an array of radio receivers

• US 10,401,472 B2
• Filed: 01/18/2018
• Issued: 09/03/2019
• Est. Priority Date: 01/18/2018
• Status: Active Grant

• Current Assignee: Ciholas, Inc.
• Original Assignee: Ciholas, Inc.
• Inventors: Ciholas, Mike, Bennett, Justin E
• Primary Examiner(s): Nguyen, Khai M
• Application Number:
  US15/874,513
• Publication Number:
  US 20190219664A1
• Time in Patent Office: 593 Days
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 3/023 Monitoring or calibrating
• CPC Class Codes: G01S 3/28 using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A system and method for determining the range, angle, and elevation of a target object having a radio transceiver relative to a known location is provided. The system includes a primary radio transceiver located an initially unknown distance from the target object, and at least one auxiliary radio receiver located a known distance and angle relative to a reference bearing from the primary radio transceiver. The system further includes a processing unit in communication with the primary radio transceiver and at least one auxiliary receiver. The processing unit is capable of calculating the range between the primary and the target object and the angle to the target object relative to the reference bearing. The method includes the steps of: (1) acquiring range data between at least a primary radio transceiver of the system and the target object using two way ranging; (2) transmitting the range data to a processing unit that is in communication with the primary radio transceiver and at least one auxiliary radio receiver; (3) calculating the range between the primary radio transceiver and the target object using two way ranging algorithms at the processing unit; (4) acquiring time of arrival data for signals exchanged between the target object and the at least one auxiliary radio receiver; and (5) determining the angle of the target object relative to a reference bearing from the primary radio transceiver of the system by running the time of arrival data from the tracked object through an algorithm.

Claims

1. A system for determining the range and direction of a target object in an unknown location relative to a locator unit comprising:

a. a radio transceiver associated with the target object;

b. a locator unit comprising;

i. a primary radio transceiver located in a first known location on the locator unit;

ii. a plurality of auxiliary radio receivers, each auxiliary receiver positioned at a known location on the locator unit relative to the primary radio transceiver;

c. a processing unit in communication with said primary radio transceiver and said plurality of auxiliary receivers, said processing unit capable of calculating the range between the primary radio transceiver and the target object, and the direction to the target object.

2. The system for determining the range and direction of a target object according to claim 1 wherein the primary radio transceiver and said plurality of auxiliary radio receivers transmit and receive ultra-wideband signals.

3. The system for determining the range and direction of a target object according to claim 1 wherein the plurality of auxiliary radio receivers are arranged in a circular pattern around the primary radio transceiver.

4. The system for determining the range and direction of a target object according to claim 1 wherein a plurality of systems are provided and arranged in a spatially diverse pattern.

5. The system for determining the range and direction of a target object according to claim 1 wherein said plurality of auxiliary receivers comprises at least three auxiliary radio receivers arranged in a spatially diverse pattern in three dimensions, and said processing unit is capable of calculating the elevation of the target object.

6. A system for determining the range, direction and elevation of a target object in an unknown location relative to a locator unit comprising:

a. a target object having a radio transceiver;

b. a locator unit comprising;

i. a primary radio transceiver located in a first known location on the locator unit;

ii. at least three auxiliary radio receivers, each auxiliary receiver positioned at a known location on the locator unit relative to the primary radio transceiver;

c. a processing unit in communication with said primary radio transceiver and said plurality of auxiliary receivers, said processing unit capable of calculating the range between the primary radio transceiver and the target object, the direction to the target object, and the elevation of the target object.

7. The system for determining the range, direction and elevation of a target object according to claim 6 wherein the primary radio transceiver and at least three auxiliary radio receivers transmit and receive ultra-wideband signals.

8. A method for determining the range and direction of a target object relative to a known location comprising the steps of:

a. acquiring timing data of transmit and receive times of packets between at least a primary radio transceiver located in a first known coordinate location and the target object;

b. calculating a first distance (d_tp) between the primary radio transceiver and the target object based on the acquired timing data using two way ranging algorithms;

c. acquiring time of arrival data for signals exchanged between the target object and said primary radio transceiver and between the target object and each of a plurality of auxiliary radio receivers positioned at a known coordinate location relative to the primary radio transceiver;

d. selecting an arbitrary point x_n on an arc located at the first distance (d_tp) from the primary radio transceiver;

e. computing the estimated time of arrival data for signals between the arbitrary point x_n and said primary radio transceiver and between the arbitrary point x_n and each of said plurality of auxiliary radio receivers based on the known coordinate location of the arbitrary point x_n, the known coordinate location of the primary radio auxiliary radio receivers;

f. comparing the actual measured time of arrival data for the target object to the estimated time of arrival data for the arbitrary point x_n;

g. determining whether the estimated time of arrival data for the arbitrary point x_n is within an acceptable margin of error to the actual measured time of arrival data for the target object;

h. if the estimated time of arrival data for the arbitrary point x_n is not within the acceptable margin of error, selecting a further arbitrary point X_n+1 along the arc;

i. repeating steps e-h for each further arbitrary point X_n+1 until an acceptable margin of error is reached.

9. The method for determining the range and direction of a target object according to claim 8 wherein the step of selecting a further arbitrary point X_n+1 along the arc comprises the steps of:

a. comparing the acquired timing data of transmit and receive time packets to the computed estimated time of arrival data for each auxiliary radio transceiver;

b. generating a vector from the point x_n for each auxiliary radio receiver indicative of the magnitude of the difference between acquired timing data and the computed estimated time of arrival data;

c. summing the vectors generated to obtain a resulting vector;

d. selecting the next arbitrary point X_n+1 along the arc in the direction of the resulting vector.

10. The method for determining the range and direction of a target object according to claim 8 wherein a processing unit that is in communication with the primary radio transceiver and said plurality of auxiliary radio receivers is provided to make the calculations and computations based on the timing data.

11. The method for determining the range and direction of a target object according to claim 8 wherein the step of selecting the arbitrary point x_n is preceded by ascertaining which one of the plurality of auxiliary radio receivers is nearest the target object;

and the step of selecting the arbitrary point x_n includes selecting a point on the arc that is closest to the nearest auxiliary radio receiver.

12. The method for determining the range and direction of a target object according to claim 8 further comprising the steps of:

a. storing the determined position of the target object after the acceptable margin of error is reached; and

b. re-checking the angle of the target object to the primary radio transceiver by beginning with the stored position of the target object instead of the arbitrary point in step (d).

13. The method for determining the range and direction of a target object according to claim 8, wherein said plurality of auxiliary radio receivers comprises at least three auxiliary radio receivers arranged in a spatially diverse pattern in three dimensions and said arc is a three-dimensional sphere.

14. The method for determining the range and direction of a target object according to claim 8 wherein the positions of the primary radio transceiver and plurality of auxiliary radio receivers are selected to optimize angular accuracy in one or more directions to optimize accuracy for a particular area.

15. The method for determining the range and direction of a target object according to claim 8 wherein the time of arrival data for signals exchanged between the target object, the primary radio transceiver, and each of a plurality of auxiliary radio receivers is assigned a weight based on signal quality.

16. A method for determining the range, direction and elevation of a target object in three dimensions relative to a known location comprising the steps of:

a. acquiring timing data of transmit and receive times of packets between at least a primary radio transceiver located in a first known location and the target object;

b. calculating a first distance (d_tp) between the primary radio transceiver and the target object based on the acquired timing data using two way ranging algorithms;

c. acquiring time of arrival data for signals exchanged between the target object and said primary radio transceiver and between the target object and each of at least three auxiliary radio receivers positioned at a known coordinate location relative to the primary radio transceiver and arranged in a spatially diverse pattern in three dimensions;

d. selecting an arbitrary point x_n on a sphere located at the first distance (d_tp) from the primary radio transceiver;

e. computing the estimated time of arrival data for signals between the arbitrary point x_n and said primary radio transceiver and between the arbitrary point x_n and each of said at least three auxiliary radio receivers based on the known coordinate location of the arbitrary point x_n,, the known coordinate location of the primary radio transceiver, and the known coordinate locations of each of the at least three auxiliary radio receivers;

f. comparing the actual measured time of arrival data for the target object to the estimated time of arrival data for the arbitrary point x_n;

g. determining whether the estimated time of arrival data for the arbitrary point x_n is within an acceptable margin of error to the actual measured time of arrival data for the target object;

h. if the estimated time of arrival data for the arbitrary point x_n is not within the acceptable margin of error, selecting a further arbitrary point X_n+1 that is nearer the target object along the sphere than the previous arbitrary point x_n;

i. repeating steps e-h for each further arbitrary point X_n+1 until an acceptable margin of error is reached.

17. The method for determining the range and direction of a target object according to claim 16 wherein the step of selecting a further arbitrary point X_n+1 along the arc comprises the steps of:

a. comparing the acquired timing data of transmit and receive time packets to the computed estimated time of arrival data for each auxiliary radio transceiver;

b. generating a vector from the point x_n for each auxiliary radio receiver indicative of the magnitude of the difference between acquired timing data and the computed estimated time of arrival data;

c. summing the vectors generated to obtain a resulting vector;

d. selecting the next arbitrary point X_n+1 along the arc in the direction of the resulting vector.

18. The method for determining the range, direction and elevation of a target object according to claim 16 wherein a processing unit that is in communication with the primary radio transceiver and said at least three auxiliary radio receivers is provided to make the calculations and computations based on the timing data.

19. The method for determining the range, direction and elevation of a target object according to claim 16 wherein the step of selecting the arbitrary point x_n is preceded by ascertaining which one of the three or more auxiliary radio receivers is nearest the target object;

and the step of selecting the arbitrary point x_n includes selecting a point on the sphere that is closest to the nearest auxiliary radio receiver.

20. The method for determining the range, direction and elevation of a target object according to claim 16 further comprising the steps of:

a. storing the determined position of the target object after the acceptable margin of error is reached; and

b. re-checking the angle of the target object to the primary radio transceiver by beginning with the stored position of the target object instead of the arbitrary point in step (d).