Detecting roadway targets within a multiple beam radar system

• US 10,049,569 B2
• Filed: 06/20/2016
• Issued: 08/14/2018
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Wavetronix
• Original Assignee: Wavetronix
• 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:
  US15/187,508
• Publication Number:
  US 20160300487A1
• Time in Patent Office: 785 Days
• Field of Search: 340907, 340916, 340917, 340933, 340941-943, 343700 MS, 342104, 342118, 342147
• 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 traffic sensor for monitoring a roadway, the traffic sensor comprising:

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

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

detect one or more targets in the plurality of beams of the radar system;

compute a first position for one or more detected targets for a first detection period;

compute a second position for one or more detected targets for a second detection period;

derive at least one filtered computed position for at least one of the one or more detected targets using the first computed position from the first detection period and the second computed position from the second detection period.

2. The traffic sensor of claim 1, wherein deriving a filtered computed position for the one or more detected targets further comprises using an additional subset of computed positions from the first detection period.

3. The traffic sensor of claim 1, wherein deriving a filtered computed position for the one or more detected targets further comprises using an additional subset of computed positions from the second detection period.

4. The traffic sensor of claim 1, wherein deriving a filtered computed position for the one or more targets further comprises using a subset of both the first computed position from the first detection period and the second computed positions from the second detection period.

5. The traffic sensor of claim 1, wherein the radar system comprises:

transmit antennas including a plurality of beams and configured to transmit signals into the roadway using the plurality of beams, the signals being frequency modulated continuous wave radio frequency signals; and

receive antennas configured to receive the reflections of signals off of objects in the roadway using the plurality of beams.

6. The traffic sensor of claim 1, wherein the computer system comprises:

system memory;

one or more processors electronically coupled to the system memory;

at least one computer-readable storage device electronically coupled to the one or more processors, the at least one computer-readable storage device having stored thereon instructions that when executed by the one or more processors cause the computer system to detect the one or more targets, compute the first positions for the first detection period, compute the second positions for the second detection period, and derive the filtered computed positions.

7. The traffic sensor of claim 1, wherein detecting one or more targets in the plurality of beams of the radar system comprises identifying at least one energy peak within a multi-beam image generated using the radar system'"'"'s plurality of beams.

8. The traffic sensor of claim 1, wherein the first and second computed positions are stored in a target list.

9. The traffic sensor of claim 8, wherein if the computed positions stored in the target list are within a specified distance of a last known position for at least one of the one or more detected targets, the computer system determines that the computed positions from the target list represent new positions for an existing target.

10. A traffic control system comprising:

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

a radar system including a plurality of beams and 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;

detect one or more targets in the plurality of beams of the radar system;

compute first positions for the one or more targets for a first detection period;

compute second positions for the one or more targets for a second detection period; and

filter the computed position of at least one of the one or more detected targets using one or more first computed positions from the first detection period and one or more second computed positions from the second detection period.

11. The traffic control system recited in claim 10, wherein the computer system is further configured to filter the computed position through both spatial and temporal filtering.

12. The traffic control system recited in claim 10, wherein the traffic control system further comprises a traffic control device configured to actuate a traffic signal based on the at least one filtered computed position for the one or more targets.

13. The traffic control system recited in claim 10, wherein the computer system is further configured to send a signal to a traffic control device configured to actuate a traffic signal based on the filtered position for the one or more targets.

14. The traffic control system recited in claim 10, further comprising a second traffic sensor for monitoring a second roadway.

15. The traffic control system recited in claim 14, further comprising:

a second traffic control device configured to actuate a second traffic signal based on input from the second traffic sensor; and

a data network that links the sensor and traffic control device with the second sensor and second traffic control device.

16. A method for deriving filtered positions for targets detected in a roadway across a plurality of beams of a radar system, the method comprising:

detecting one or more targets in the plurality of beams of the radar system;

computing a first position for one or more detected targets for a first detection period;

computing a second position for one or more detected targets for a second detection period;

deriving at least one filtered computed position for at least one of the one or more detected targets using the first computed position from the first detection period and the second computed position from the second detection period.

17. The method of claim 16, wherein target positions for the one or more detected targets are computed based on a magnitude of identified energy in a specified area of the roadway that is covered by the plurality of beams of the radar system.

18. The method of claim 17, wherein the target positions for the one or more detected targets are further based on a specified range bin and a magnitude of identified energy in one or more surrounding adjacent range bins.

19. The method of claim 17, wherein at least one of the computed target positions includes coordinates indicating a two-dimensional position of a vehicle in the roadway.

20. The method of claim 19, wherein centroid coordinates are calculated using the following equation: