2-D Object Detection in Radar Applications

• US 20160245911A1
• Filed: 05/13/2014
• Published: 08/25/2016
• Est. Priority Date: 07/15/2013
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Wang, Dan, Ali, Murtaza
• Granted Patent: US 9,594,159 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242
• CPC Class Codes: G01S 13/581 using transmission of interrupted pulse modulated waves and based upon the Doppler effect resulting from movement of targets
• CPC Class Codes: G01S 13/72 for two-dimensional tracking, e.g. combination of angle and range tracking, track-while-scan radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9315 Monitoring blind spots
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals
• CPC Class Codes: G01S 7/2922 by using a controlled threshold
• CPC Class Codes: G01S 7/2927 by deriving and controlling a threshold value
• CPC Class Codes: G01S 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

A set of radar data is organized as a two dimensional (2D) array with multiple lines of data. A 2D cross point analysis is performed on each set of data to detect objects in range of the radar system. A set of candidate objects is identified by performing an initial one dimensional (1D) analysis on a line of data along a first axis of the set if data to determine a candidate location of each candidate object along the first axis; however, the set of candidate objects may include false objects. The set of candidate objects is pruned by performing a cross 1D analysis of the data along a second axis of the set of data at a position corresponding to each candidate location along the first axis to select a set of most likely candidate objects from the set of candidate objects.

Claims

1. A method for detecting an object in a radar system, the method comprising:

transmitting a radio signal from the radar system towards one or more objects;

receiving radio signals reflected from the one or more objects by the radar system, wherein the received radio signals include clutter signals;

forming a set of data periodically from the received signals, wherein the set of data is organized as a two dimensional (2D) array having a plurality of lines of data; and

performing a 2D cross point analysis of each set of data to detect the one or more objects, wherein the 2D cross point analysis comprises;

identifying a set of candidate objects by performing an initial one dimensional (1D) analysis on a line of data along a first axis of the set if data to determine a candidate location of each candidate object along the first axis, wherein the set of candidate objects includes false objects; and

pruning the set of candidate objects by performing a cross 1D analysis of the data along a second axis of the set of data at a position corresponding to each candidate location along the first axis to select a set of most likely candidate objects from the set of candidate objects.

2. The method of claim 1, wherein a candidate location is selected in the initial 1D analysis for each location along the first axis at which signal strength exceeds a detection threshold value;

and

further comprising performing a second initial 1D analysis in a neighborhood of each candidate location in which the detection threshold value is reduced by a fixed amount below the signal strength at each candidate location to select additional candidate locations along the first axis.

3. The method of claim 1, wherein receiving the radio signals comprises mixing the received radio signals with a copy of the transmitted signal to form beat signals;

and wherein forming each set of data comprises processing the beat signals using Fast Fourier Transforms (FFT) to form a set of FFT index values.

4. The method of claim 1, wherein each set of data corresponds to a frame period that includes multiple chirps of a frequency modulated continuous wave transmitted signal.

5. The method of claim 1, wherein each set of data corresponds to a pulse period of a pulsed transmitted signal.

6. The method of claim 1, wherein the first axis represents range data and the second axis represents doppler data.

7. The method of claim 1, wherein the first axis represents Doppler data and the second axis represents range data.

8. The method of claim 2, wherein the second initial 1D analysis for a candidate location in a line of data is performed before performing a first initial 1D analysis on a next line of data.

9. The method of claim 2, wherein the detection threshold for the second initial 1D analysis is reduced by an amount that varies along the first axis.

10. The method of claim 2, wherein a size of the neighborhood for the second initial 1D analysis of each candidate object is selected based on a location of each candidate object along the first axis.

11. A non-transitory computer-readable medium storing software instructions that, when executed by a processor, cause a method for detecting an object in a radar system to be performed, the method comprising:

transmitting a radio signal from the radar system towards one or more objects;

receiving radio signals reflected from the one or more objects by the radar system, wherein the received radio signals include clutter signals;

forming a set of data periodically from the received signals, wherein the set of data is organized as a two dimensional (2D) array having a plurality of lines of data; and

performing a 2D cross point analysis of each set of data to detect the one or more objects, wherein the 2D cross point analysis comprises;

identifying a set of candidate objects by performing an initial one dimensional (1D) analysis on a line of data along a first axis of the set if data to determine a candidate location of each candidate object along the first axis, wherein the set of candidate objects includes false objects; and

pruning the set of candidate objects by performing a cross 1D analysis of the data along a second axis of the set of data at a position corresponding to each candidate location along the first axis to select a set of most likely candidate objects from the set of candidate objects.

12. The method of claim 11, wherein a candidate location is selected in the initial 1D analysis for each location along the first axis at which signal strength exceeds a detection threshold value;

and

further comprising performing a second initial 1D analysis in a neighborhood of each candidate location in which the detection threshold value is reduced by a fixed amount below the signal strength at each candidate location to select additional candidate locations along the first axis.

13. A radar system comprising:

a transmitter operable to provide a radio signal for transmission from the radar system towards one or more objects;

a receiver configured to receive radio signals reflected from the one or more objects by the radar system, wherein the received radio signals include clutter signals; and

a signal processing module coupled to the receiver, wherein the signal processing module is configured to perform a signal processing method comprising;

forming a set of data periodically from the received signals, wherein the set of data is organized as a two dimensional (2D) array having a plurality of lines of data;

performing a 2D cross point analysis of each set of data to detect the one or more objects, wherein the 2D cross point analysis comprises;

identifying a set of candidate objects by performing an initial one dimensional (1D) analysis on a line of data along a first axis of the set if data to determine a candidate location of each candidate object along the first axis, wherein the set of candidate objects includes false objects; and

pruning the set of candidate objects by performing a cross 1D analysis of the data along a second axis of the set of data at a position corresponding to each candidate location along the first axis to select a set of most likely candidate objects from the set of candidate objects.

14. The radar system of claim 13, wherein a candidate location is selected in the initial 1D analysis for each location along the first axis at which signal strength exceeds a detection threshold value;

and

further comprising performing a second initial 1D analysis in a neighborhood of each candidate location in which the detection threshold value is reduced by a fixed amount below the signal strength at each candidate location to select additional candidate locations along the first axis.

15. The radar system of claim 13, wherein each set of data corresponds to a frame period that includes multiple chirps of a frequency modulated continuous wave transmitted signal.

16. The radar system of claim 13, wherein each set of data corresponds to a pulse period of a pulsed transmitted signal.

17. The radar system of claim 13, wherein the first axis represents range data and the second axis represents Doppler data.

18. The radar system of claim 13, wherein the first axis represents Doppler data and the second axis represents range data.

19. The radar system of claim 13, wherein the second initial 1D analysis for a candidate location in a line of data is performed before performing a first initial 1D analysis on a next line of data.

20. The radar system of claim 14, wherein the detection threshold for the second initial 1D analysis is reduced by an amount that varies along the first axis.