Detecting roadway targets across radar beams by creating a filtered comprehensive image

• US 9,601,014 B2
• Filed: 12/08/2015
• Issued: 03/21/2017
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Wavetronix
• Original Assignee: Wavetronic LLC
• Inventors: Arnold, David V., Jarrett, Bryan R., Karlinsey, Thomas W., Waite, Jonathan L., Giles, Brad, St. John, Randy
• Primary Examiner(s): HOFSASS, JEFFERY A
• Application Number:
  US14/962,377
• Publication Number:
  US 20160086485A1
• Time in Patent Office: 469 Days
• Field of Search: 340/907, 340/916, 340/917, 340/933, 340941-943, 343/700.MS, 342/104, 342/118, 342/147
• US Class Current: 1/1
• CPC Class Codes: G01S 13/48 using multiple beams at emission or reception
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors
• CPC Class Codes: G08G 1/08 according to detected number or speed of vehicles

Abstract

The present invention extends to methods, systems, and computer program products for detecting targets across beams at roadway intersections. Embodiments of the invention include tracking a target across a plurality of beams of a multiple beam radar system in a roadway intersection and updating track files for targets within a roadway intersection. Returns from a plurality of radar beams monitoring a roadway intersection are divided into range bins. Identified energy in the range bins is used to compute the position of targets within a roadway intersection. When the position of a target is computed, it is determined if the position is a new position for an existing target or if the position is the position of a new target.

Claims

1. A method for filtering computed target positions of targets in a roadway across a plurality of beams of a radar system, the method comprising:

creating a comprehensive image of returns from the plurality of beams from a first detection period;

creating a comprehensive image of returns from the plurality of beams from a second detection period;

creating a filtered comprehensive image by filtering the comprehensive image from the second detection period using the comprehensive image from the first detection period; and

detecting targets using the filtered comprehensive image.

4. The method of claim 1, wherein detecting one or more targets using the filtered comprehensive image includes calculating a computed position for the one or more targets.

5. The method of claim 4, wherein filtering the second comprehensive image from the second detection period using the first comprehensive image from the first detection period includes removing one or more errors from the computed position.

6. The method of claim 4, further comprising generating one or more track files based on the returns from the plurality of beams during at least the first or the second detection periods.

7. The method of claim 6, wherein the computed positions are filtered using the generated track files.

8. The method of claim 1, wherein a multi-beam image is identified from within the returns from the scanning system, the multi-beam image spanning a sub-plurality of the plurality of beams and spanning a plurality of range bins within a grid.

9. The method of claim 8, wherein detecting one or more targets using the filtered comprehensive image comprises identifying at least one energy peak within the multi-beam image.

2. A traffic control system comprising:

a traffic sensor for monitoring a roadway, the traffic sensor comprising;

a radar system configured to transmit a signal into the roadway and to receive reflections of the signal off of objects in the roadway using a plurality of beams; and

a computer system coupled to the radar system and configured to;

divide returns from the plurality of beams during a first detection period into a grid of range bins,

create a comprehensive image from the returns generated during the first detection period;

divide returns from the plurality of beams during a second detection period into the grid of range bins;

create a comprehensive image from the returns generated during the second detection period;

filter the comprehensive image from the second detection period using the comprehensive image from the first detection period; and

detect a target using the filtered comprehensive image.

10. The traffic control system of claim 2, wherein the first and second returns are divided into the grid of range bins where each range bin in the grid of range bins is a uniform varied distance from the multiple beam radar system.

11. The traffic control system of claim 10, wherein each beam is divided into a plurality of range bins in accordance with the uniform varied distances from the multiple beam radar system.

12. The traffic control system of claim 2, wherein creating the first comprehensive image includes organizing the divided first returns for each of the beams of the multiple beam radar system into a block of memory.

13. The traffic control system of claim 2, wherein detecting at least one target using the filtered comprehensive image comprises comparing energy returns in one or more range bins of the grid of range bins to a specified magnitude energy threshold.

14. The traffic control system of claim 13, wherein range bins having energy returns greater than or equal to the magnitude energy threshold are identified as including a potential target.

15. The traffic control system of claim 14, wherein the traffic sensor is configured to determine whether the magnitude of identified energy from a range bin that includes a potential target is an energy peak that is higher than energy values in surrounding adjacent range bins.

16. The traffic control system of claim 15, wherein the traffic sensor computes the position of the at least one target using the magnitude of energy in the range bin determined to include the potential target and the magnitude of energy in the surrounding adjacent range bins.

3. A traffic control system comprising:

a traffic sensor for monitoring a roadway, the traffic sensor comprising;

a radar system including a plurality of beams configured to transmit a signal into the roadway and to receive reflections of the signal off of objects in the roadway using the plurality of beams; and

a computer system coupled to the radar system and configured to;

create a comprehensive image of returns from the plurality of beams from a first detection period;

create a comprehensive image of returns from the plurality of beams from a second detection period;

create a filtered comprehensive image by filtering the comprehensive image from the second detection period using the comprehensive image from the first detection period; and

detect targets using the filtered comprehensive image.

17. The traffic control system of claim 3, wherein the radar system further comprises:

at least one transmit antenna for transmitting signals into the roadway using the plurality of beams; and

at least one receive antenna for receiving the reflections of the signals.

18. The traffic control system of claim 3, wherein the signals are frequency modulated continuous wave radio frequency signals.

19. The traffic control system of claim 3, wherein detecting one or more targets using the filtered comprehensive image comprises comparing differences between the first and second comprehensive images, the comparison including subtracting returns in the first comprehensive image from returns in the second comprehensive image.

20. The traffic control system of claim 3, wherein filtering the second comprehensive image from the second detection period using the first comprehensive image from the first detection period includes spatial and temporal filtering in which a detected target position is filtered in position and in time.