Single pulse imaging radar system and method

• US 7,535,412 B1
• Filed: 01/25/2007
• Issued: 05/19/2009
• Est. Priority Date: 01/25/2007
• Status: Expired due to Fees

• Current Assignee: Navy The USA As Represented By The Secretary of The
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Shackelford, Aaron K, Blunt, Shannon D, Gerlach, Karl R
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/626,935
• Time in Patent Office: 845 Days
• Field of Search: 342 25 R- 25 F, 342/118, 342134-144, 342/175, 342/176, 342/179, 342190-197, 342/22, 342/59, 342 82-103, 342/159, 342200-205, 735/70, 735/84, 735/96, 736/18, 736/20, 736/25, 736/27, 736/28
• US Class Current: 342/179
• CPC Class Codes: G01S 13/28 with time compression of received pulses
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period

Abstract

A single pulse imaging (SPI) radar system for creating a radar image from a plurality of Doppler phase-shifted return radar signals in a radar environment of moving targets includes a transmitter; a receiver for receiving a radar return signal; an analog-to-digital converter (ADC) coupled to the output of the receiver; a processor, coupled to the output of the ADC, that is programmed with an SPI algorithm that includes a bank of range/Doppler-dependent adaptive RMMSE-based filters; and a target detector. The algorithm estimates adaptively a range profile for each of the Doppler phase-shifted return radar signals to create the radar image of the moving targets.

Claims

1. A method for radar imaging using a single transmitted radar pulse, comprising:

a) transmitting a single radar pulse toward a plurality of moving targets;

b) receiving a plurality of return reflected radar signals; and

c) estimating adaptively a range-Doppler profile for each of the plurality of return reflected radar signals to thereby produce a radar image of the plurality of moving targets from said estimated range-Doppler profiles, and

wherein steps a)-c) are conducted in a single operational radar pulse cycle.

2. A method as in claim 1, wherein the estimating adaptively is performed with reiterative minimum mean-square error (RMMSE) estimation.

3. A method as in claim 2, wherein a cost function J_k(λ

)=E[|x_k(λ

)−

w_k^H(λ

)y(λ

)|²] is minimized for each range profile, where w_k(λ

) is the APC weight vector for the λ

^th range cell in the range profile with Doppler phase shift θ

_k, and E[□

] is the expectation operator.

4. A method as in claim 1, wherein the single transmitted radar pulse waveform has a thumbtack type ambiguity function.

5. A single pulse imaging (SPI) radar system for obtaining from a single transmitted radar pulse a radar image of a plurality of moving targets from a plurality of Doppler phase-shifted return radar signals reflected from the plurality of moving targets, comprising:

a receiver for receiving a radar return signal;

a processor coupled to the receiver and programmed with an SPI algorithm that includes a bank of range/Doppler-dependent adaptive RMMSE-based filters for estimating adaptively a range profile for each of the Doppler phase-shifted return radar signals to thereby produce the radar image of the plurality of moving targets from said estimated range-Doppler profiles; and

a target detector,

and wherein said SPI algorithm obtains said radar image in a single operational radar pulse cycle.

6. A radar system as in claim 5, wherein the estimating adaptively is performed with reiterative minimum mean-square error (RMMSE) estimation.

7. A radar system as in claim 6, wherein a cost function J_k(λ

)=E[|x_k(λ

)−

w_k^H(λ

)y(λ

)|²] is minimized for each range profile, where w_k (λ

) is the APC weight vector for the λ

^th range cell in the range profile with Doppler phase shift θ

_k, and E[□

] is the expectation operator.

8. A radar system as in claim 5, wherein the single transmitted radar pulse waveform has a thumbtack type ambiguity function.

9. A radar system as in claim 5, further comprising a transmitter configured to periodically transmit a single radar pulse.

10. A radar system as in claim 5, further comprising an analog-to-digital converter (ADC) coupled between the receiver and the processor.

11. A radar system as in claim 10, further comprising a transmitter configured to periodically transmit a single radar pulse.

12. A single pulse imaging (SPI) radar system for obtaining from a single transmitted radar pulse a radar image of a plurality of moving targets from a plurality of Doppler phase-shifted return radar signals reflected from the plurality of moving targets, comprising:

a transmitter;

a receiver for receiving a radar return signal;

an analog-to digital converter (ADC) coupled to the output of the receiver;

a processor coupled to the output of the ADC and programmed with an SPI algorithm that includes a bank of range/Doppler-dependent adaptive RMMSE-based filters for estimating adaptively a range-Doppler profile for each of the Doppler phase-shifted return radar signals to thereby produce the radar image of the plurality of moving targets from said estimated range-Doppler profiles; and

a target detector,

and wherein said SPI algorithm obtains said radar image in a single operational radar pulse cycle.

13. A radar system as in claim 12, wherein the estimating adaptively is performed with reiterative minimum mean-square error (RMMSE) estimation.

14. A radar system as in claim 13, wherein a cost function J_k(λ

)=E[|x_k(λ

)−

w_k^H(λ

)y(λ

)|²] is minimized for each range profile, where w_k(λ

) is the APC weight vector for the λ

^th range cell in the range profile with Doppler phase shift θ

_k, and E[□

] is the expectation operator.

15. A radar system as in claim 12, wherein the single transmitted radar pulse waveform has a thumbtack type ambiguity function.