Radar system with phase based multi-target detection

• US 9,784,820 B2
• Filed: 09/19/2014
• Issued: 10/10/2017
• Est. Priority Date: 09/19/2014
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Arage, Alebel Hassen
• Primary Examiner(s): BYTHROW, PETER M
• Application Number:
  US14/491,192
• Publication Number:
  US 20160084941A1
• Time in Patent Office: 1,117 Days
• Field of Search: 342 70- 72
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/4454 phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period
• CPC Class Codes: G01S 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/41 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

A radar system includes a plurality of antennas and a controller. The plurality of antennas is configured to detect a reflected radar signal reflected by an object in a field-of-view of the system. Each antenna of the plurality of antennas is configured to output a detected signal indicative of the reflected radar signal detected by the antenna. The controller is configured to receive detected signals from the plurality of antennas, and determine if a target is present in the field-of-view based on the detected signals. The controller is also configured to determine if the target includes more than one object based on an analysis of phases of the detected signals.

Claims

1. A radar system comprising:

a plurality of antennas configured to detect a reflected radar signal reflected by an object in a field-of-view of the system, wherein each antenna of the plurality of antennas is configured to output a detected signal indicative of the reflected radar signal detected by each of the antenna; and

a controller configured to

receive the detected signals from the plurality of antennas,

determine if a target is present in the field-of-view based on the detected signals,

determine a frequency profile of each of the detected signals from each of the antenna, wherein the frequency profile is characterized by values stored in an array of frequency bins, and

determine a phase difference of each frequency profile at two distinct frequencies of an antenna, wherein the phase difference is determined based on a difference between a first phase value associated with a first frequency bin of the array, and a second phase value associated with a second frequency bin of the array, and

determine if the target includes more than one object based on an analysis of phase differences of the frequency profile of each the detected signals.

2. The system in accordance with claim 1, wherein the frequency profile is characterized as a range profile based on a frequency transformation of a time-domain sample of the detected signal from one antenna.

3. The system in accordance with claim 1, wherein the frequency profile is characterized as a Doppler profile based on a frequency transformation of a time-domain sample of the detected signal from one antenna.

4. The system in accordance with claim 1, wherein a reference frequency bin is associated with a maximum amplitude value, the first frequency bin is adjacent to the reference frequency bin and associated with a lower frequency than the reference frequency bin, and the second frequency bin is adjacent to the reference frequency bin and associated with a higher frequency than the reference frequency bin.

5. The system in accordance with claim 1, wherein the controller is further configured to

determine a phase slope based on a trend in the phase difference versus a relative position of each antenna, and

indicate that the target includes more than one object if the phase slope has a magnitude greater than a slope threshold.

6. The system in accordance with claim 1, wherein the controller is further configured to

determine a phase variation based on changes in the phase difference versus a relative position of each antenna, and

indicate that the target includes more than one object if the phase variation is greater than a variation threshold.

7. A controller for a radar system, said controller comprising:

a receiver configured to receive detected signals from a plurality of antennas configured to detect a reflected radar signal reflected by an object in a field-of-view of the system, wherein each antenna of the plurality of antennas is configured to output a detected signal indicative of the reflected radar signal detected by each of the antenna; and

a processor configured to

receive the detected signals from the plurality of antennas,

determine if a target is present in the field-of-view based on the detected signals,

determine a frequency profile of each of the detected signals from each of the antenna, wherein the frequency profile is characterized by values stored in an array of frequency bins, and

determine a phase difference of each frequency profile at two distinct frequencies of an antenna, wherein the phase difference is determined based on a difference between a first phase value associated with a first frequency bin of the array, and a second phase value associated with a second frequency bin of the array, and

determine if the target includes more than one object based on an analysis of phase differences of the frequency profile of each the detected signals.

8. A method of operating a radar system comprising:

receiving detected signals from a plurality of antennas configured to detect a reflected radar signal reflected by an object in a field-of-view of the antennas, wherein each antenna of the plurality of antennas is configured to output a detected signal indicative of the reflected radar signal detected by each of the antenna; and

determining if a target is present in the field-of-view based on the detected signals;

determining a frequency profile of each of the detected signals from each of the antenna, wherein the frequency profile is characterized by values stored in an array of frequency bins, and

determining a phase difference of each frequency profile at two distinct frequencies of an antenna, wherein the phase difference is determined based on a difference between a first phase value associated with a first frequency bin of the array, and a second phase value associated with a second frequency bin of the array, and

determining if the target includes more than one object based on an analysis of phase differences of the frequency profile of each the detected signals.

9. The method in accordance with claim 8, wherein the frequency profile is characterized as a range profile based on a frequency transformation of a time-domain sample of the detected signal from one antenna.

10. The method in accordance with claim 8, wherein the frequency profile is characterized as a Doppler profile based on a frequency transformation of a time-domain sample of the detected signal from one antenna.

11. The method in accordance with claim 8, wherein a reference frequency bin is associated with a maximum amplitude value, the first frequency bin is adjacent to the reference frequency bin and associated with a lower frequency than the reference frequency bin, and the second frequency bin is adjacent to the reference frequency bin and associated with a higher frequency than the reference frequency bin.

12. The method in accordance with claim 8, wherein the method includes

determining a phase slope based on a trend in the phase difference versus a relative position of each antenna, and

indicating that the target includes more than one object if the phase slope has a magnitude greater than a slope threshold.

13. The method in accordance with claim 8, wherein the method includes

determining a phase variation based on changes in the phase difference versus a relative position of each antenna, and

indicating that the target includes more than one object if the phase variation is greater than a variation threshold.