Pulse-doppler rada measurement of crossing target dynamics

• US 10,126,418 B1
• Filed: 09/08/2015
• Issued: 11/13/2018
• Est. Priority Date: 09/08/2015
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Waymo LLC (Alphabet Inc.)
• Inventors: Campbell, Timothy
• Primary Examiner(s): Windrich, Marcus E
• Application Number:
  US14/847,579
• Time in Patent Office: 1,162 Days
• Field of Search: 342 70- 72
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242
• CPC Class Codes: G01S 13/5246 post processors for coherent MTI discriminators, e.g. residue cancellers, CFAR after Doppler filters
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period

Abstract

Disclosed herein are embodiments that relate to crossing target dynamics for a radar system. In one aspect, the present application describes a method for use with a radar system. The method includes transmitting at least one signal pulse. The method also includes receiving a signal associated with reflection of the at least one transmitted signal pulse. Further, the method may also include processing the received signal to determine a cross-range rate. The processing may include determining a Doppler bandwidth based on the received signal. Additionally, the processing may include determining a range based on the received signal. Yet further, the processing may include determining a cross-range extent based on the received signal. Additionally, the processing may include determining the cross-range rate for the target object based on the determined Doppler bandwidth, range, and cross-range extent. An autonomous vehicle may be controlled based on the determined cross-range rate.

Claims

1. A method, comprising:

transmitting, by a radar unit, at least one signal pulse;

receiving, by the radar unit, a signal associated with reflection of the at least one transmitted signal pulse;

processing the received signal to determine a cross-range rate for a target object, wherein the processing comprises;

determining a Doppler bandwidth based on the received signal, wherein the Doppler bandwidth represents a difference between a first Doppler shift and a second Doppler shift within a Doppler subband;

determining a range based on the received signal;

determining a cross-range extent based on the received signal; and

determining the cross-range rate for the target object based on the determined Doppler bandwidth, range, and cross-range extent, wherein the cross-range rate is calculated by dividing the Doppler bandwidth by the arctangent of the cross-range extent divided by the range; and

controlling an autonomous vehicle based on the determined cross-range rate.

2. The method according to claim 1, wherein the cross-range extent is determined based on a number of range filters over which a reflection in the received signal is observed.

3. The method according to claim 1, further comprising identifying two scatterers associated with the received signal.

4. The method according to claim 3, further comprising performing the processing for the two scatterers.

5. The method according to claim 4, further comprising determining whether the two scatterers are both part of the target object.

6. The method according to claim 5, further comprising determining the cross-range extent for the target object based on the two scatters responsive to determining that the two scatterers are both part of the target object.

7. A radar system comprising:

a radar unit comprising;

a transmitter configured to transmit at least one signal pulse;

a receiver configured to receive a signal associated with reflection of the at least one transmitted signal pulse;

a processing unit configured to perform processing comprising;

determining a Doppler bandwidth based on the received signal, wherein the Doppler bandwidth represents a difference between a first Doppler shift and a second Doppler shift within a Doppler subband;

determining a range based on the received signal;

determining a cross-range extent based on the received signal; and

determining a cross-range rate for the target object based on the determined Doppler bandwidth, range, and cross-range extent, wherein the cross-range rate is determined by dividing the Doppler bandwidth by the arctangent of the cross-range extent divided by the range; and

controlling an autonomous vehicle based on the determined cross-range rate.

8. The system according to claim 7, wherein the processing unit is further configured to calculate the cross-range rate by dividing the Doppler bandwidth by the arctangent of the cross-range extent divided by the range.

9. The system according to claim 7, wherein the processing unit is further configured to determine the cross-range extent based on a number of range filters over which a reflection in the received signal is observed.

10. The system according to claim 7, wherein the processing unit is further configured to identify two scatterers associated with the received signal.

11. The system according to claim 10, wherein the processing unit is further configured to perform the processing for the two scatterers.

12. The system according to claim 11, wherein the processing unit is further configured to determine whether the two scatterers are both part of the target object.

13. The system according to claim 12, wherein the processing unit is further configured to determine the cross-range extent for the target object based on the two scatters responsive to determining that the two scatterers are both part of the target object.

14. An article of manufacture including a non-transitory computer-readable medium, having stored thereon program instructions that, if executed by a computing device, cause the computing device to perform operations comprising:

transmitting, by a radar unit, at least one signal pulse;

receiving, by the radar unit, a signal associated with reflection of the at least one transmitted signal pulse;

processing the received signal, wherein the processing comprises;

determining a Doppler bandwidth based on the received signal, wherein the Doppler bandwidth represents a difference between a first Doppler shift and a second Doppler shift within a Doppler subband;

determining a range based on the received signal;

determining a cross-range extent based on the received signal; and

determining a cross-range rate for the target object based on the determined Doppler bandwidth, range, and cross-range extent, wherein the cross-range rate is calculated by dividing the Doppler bandwidth by the arctangent of the cross-range extent divided by the range; and

controlling an autonomous vehicle based on the determined cross-range rate.

15. The article of manufacture according to claim 14, wherein the cross-range extent is determined based on a number of range filters over which a reflection in the received signal is observed.

16. The article of manufacture according to claim 14, further comprising identifying two scatterers associated with the received signal.

17. The article of manufacture according to claim 16, further comprising performing the processing for the two scatterers.

18. The article of manufacture according to claim 17, further comprising determining whether the two scatterers are both part of the target object.

19. The article of manufacture according to claim 18, further comprising determining the cross-range extent for the target object based on the two scatters responsive to determining that the two scatterers are both part of the target object.