Compressive radar imaging technology

• US 9,291,711 B2
• Filed: 02/25/2011
• Issued: 03/22/2016
• Est. Priority Date: 02/25/2010
• Status: Expired due to Fees

• Current Assignee: University of Maryland, College Park
• Original Assignee: University of Maryland, College Park
• Inventors: Healy, Dennis M. Jr., Patel, Vishal M., Easley, Glenn R., Chellappa, Ramalingam
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US13/035,482
• Publication Number:
  US 20140077989A1
• Time in Patent Office: 1,852 Days
• Field of Search: 342 25 R- 25 F, 342/82, 342/89, 342/90, 342/175, 342/176, 342/179, 342192-197, 342 13- 15, 342/21, 342/22, 342/118, 342/128, 342130-132, 342134-145, 324/300, 324/307, 382/100, 382/103, 382/128, 382/131, 382/232, 382/233, 382/235, 382244-253, 341/50, 341/87, 348/61, 348/143, 348/571, 702/1, 702/57, 702 66- 78, 702/127, 702189-199
• US Class Current: 1/1
• CPC Class Codes: G01S 13/90 using synthetic aperture techniques , e.g. synthetic aperture radar [SAR] techniques
• CPC Class Codes: G01S 13/904 SAR modes
• CPC Class Codes: G01S 13/9052 Spotlight mode

Abstract

A method, apparatus and computer-readable medium is provided that can utilize an undersampling method and can produce a radar image of a target. The radar image of the target can be based on a collection of waveform measurements, where the collection can be based on a significantly reduced number of transmitted and received electromagnetic pulse waveforms.

Claims

1. A method, comprising:

transmitting, by a transmitter or a transceiver of a device, a plurality of electromagnetic pulse waveforms towards a target using an undersampling method;

receiving, by a receiver or the transceiver of the device, a plurality of reflected electromagnetic pulse waveforms that are reflected by the target;

processing, by at least one hardware processor of the device, the plurality of reflected electromagnetic pulse waveforms to create a first collection of waveform measurements by converting each reflected electromagnetic pulse waveform into a waveform measurement, wherein the first collection of waveform measurements is a compressed representation of a second collection of waveform measurements;

constructing, by the at least one hardware processor of the device, the second collection of waveform measurements based on the first collection of waveform measurements using an optimization method that comprises estimating any waveform measurements of the second collection of waveform measurements not present in the first collection of waveform measurements; and

creating, by the at least one hardware processor of the device, a radar image of the target using the second collection of waveform measurements.

2. The method of claim 1, wherein the undersampling method comprises a random undersampling method that further comprises transmitting each electromagnetic pulse waveform at a non-regular pulse repetition interval.

3. The method of claim 1, wherein the undersampling method comprises a jittered undersampling method that further comprises jittering every nth transmission of an electromagnetic pulse waveform by an amount ζ

_n so that the transmission occurs at time nP+ζ

_n, where P is a sampling period.

4. The method of claim 1, wherein the converting each reflected electromagnetic pulse waveform into a waveform measurement further comprises mixing the reflected electromagnetic pulse waveform with a target electromagnetic pulse waveform and low-pass filtering the mixed electromagnetic pulse waveform,

wherein, the target electromagnetic pulse waveform simulates a return electromagnetic pulse waveform from a reference point of the target.

5. The method of claim 1, wherein the optimization method comprises a basis pursuit algorithm.

6. The method of claim 1, wherein the first collection of waveform measurements comprise noisy waveform measurements and the optimization method comprises a basis pursuit de-noising algorithm.

7. The method of claim 1, wherein the optimization method comprises an orthogonal matching pursuit.

8. The method of claim 1, wherein the optimization method comprises a Dantzig selector algorithm.

9. The method of claim 1, wherein the radar image comprises a synthetic aperture radar image.

10. An apparatus, comprising:

a memory comprising instructions;

a transceiver configured to transmit a plurality of electromagnetic pulse waveforms towards a target using an undersampling method;

wherein the transceiver is further configured to receive a plurality of reflected electromagnetic pulse waveforms that are reflected by the target;

a processor configured to process the plurality of reflected electromagnetic pulse waveforms to create a first collection of waveform measurements by converting each reflected electromagnetic pulse waveform into a waveform measurement, wherein the first collection of waveform measurements is a compressed representation of a second collection of waveform measurements;

wherein the processor is further configured to construct the second collection of waveform measurements based on the first collection of waveform measurements using an optimization method, wherein the processor is further configured to estimate any waveform measurements of the second collection of waveform measurements not present in the first collection of waveform measurements; and

wherein the processor is further configured to create a radar image of the target using the second collection of waveform measurements.

11. The apparatus of claim 10, wherein the undersampling method comprises a random undersampling method and the transceiver is further configured to transmit each electromagnetic pulse waveform at a non-regular pulse repetition interval.

12. The apparatus of claim 10, wherein the undersampling method comprises a jittered undersampling method and the transceiver is further configured to jitter every nth transmission of an electromagnetic pulse waveform by an amount ζ

_n so that the transmission occurs at time nP+ζ

_n, where P is a sampling period.

13. The apparatus of claim 10, wherein the processor is further configured to mix the reflected electromagnetic pulse waveform with a target electromagnetic pulse waveform and low-pass filter the mixed electromagnetic pulse waveform,

wherein, the target electromagnetic pulse waveform simulates a return electromagnetic pulse waveform from a reference point of the target.

14. The apparatus of claim 10, wherein the radar image comprises a synthetic aperture radar image.

15. A non-transitory computer-readable medium having a computer program stored thereon that, when executed by a processor, causes the processor to implement a method, the method comprising:

transmitting a plurality of electromagnetic pulse waveforms towards a target using an undersampling method;

receiving a plurality of reflected electromagnetic pulse waveforms that are reflected by the target;

processing the plurality of reflected electromagnetic pulse waveforms to create a first collection of waveform measurements by converting each reflected electromagnetic pulse waveform into a waveform measurement, wherein the first collection of waveform measurements is a compressed representation of a second collection of waveform measurements;

constructing the second collection of waveform measurements based on the first collection of waveform measurements using an optimization method that comprises estimating any waveform measurements of the second collection of waveform measurements not present in the first collection of waveform measurements; and

creating a radar image of the target using the second collection of waveform measurements.

16. The non-transitory computer-readable medium of claim 15, wherein the undersampling method comprises a random undersampling method that comprises transmitting each electromagnetic pulse waveform at a non-regular pulse repetition interval.

17. The non-transitory computer-readable medium of claim 15, wherein the undersampling method comprises a jittered undersampling method that comprises jittering every nth transmission of an electromagnetic pulse waveform by an amount ζ

_n so that the transmission occurs at time nP+ζ

_n, where P is a sampling period.

18. The non-transitory computer-readable medium of claim 15, wherein the converting each reflected electromagnetic pulse waveform into a waveform measurement further comprises mixing the reflected electromagnetic pulse waveform with a target electromagnetic pulse waveform and low-pass filtering the mixed electromagnetic pulse waveform,

wherein, the target electromagnetic pulse waveform simulates a return electromagnetic pulse waveform from a reference point of the target.

19. The non-transitory computer-readable medium of claim 15, wherein the radar image comprises a synthetic aperture radar image.