Monostatic radar beam optimization

• US 7,324,042 B2
• Filed: 11/15/2005
• Issued: 01/29/2008
• Est. Priority Date: 11/15/2005
• Status: Expired due to Fees

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Wooldridge, John J., Werntz, Paul C.
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US11/274,372
• Publication Number:
  US 20070109179A1
• Time in Patent Office: 805 Days
• Field of Search: 342/25.R, 342/25.F, 342/81, 342/154, 342/157, 342/158, 342159-162, 342/195, 342200-204, 342368-377
• US Class Current: 342/174
• CPC Class Codes: G01S 13/904 SAR modes
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00

Abstract

A method and system for optimizing transmit beam and receive beam antenna radiation patterns. The method includes inputting initial estimate of beam weights for a transmit beam and a receive beam to an optimizer; and using a cost function to optimize beam weights so that a response peaks in a main region and is minimized in a sidelobe region; wherein the cost function is based on using receive beam and transmit beam characteristics.

Claims

1. A method for optimizing transmit beam and receive beam radiation patterns, comprising:

inputting initial estimates of beam weights for a transmit beam and a receive beam to an optimizer; and

using a cost function to optimize the beam weights so that a response peaks in a main region and is minimized in a sidelobe region;

wherein the cost function uses characteristics of both the receive beam and the transmit beam.

2. The method of claim 1, wherein taper coefficients are used for input data signals to an array antenna, and the taper coefficients are adjusted during optimization by the optimizer, and the response is from a radar.

3. A method for optimizing transmit beam and receive beam radiation patterns, comprising:

inputting initial estimates of beam weights for a transmit beam and a receive beam to an optimizer; and

using a cost function to optimize the beam weights so that a response peaks in a main region and is minimized in a sidelobe region;

wherein the cost function is based on using characteristics of both the receive beam and the transmit beam;

the method further comprising;

(a) selecting and loading a set of taper coefficient values for input data into the array antenna;

(b) measuring a gain of the transmit beam and the receive beam of the array antenna as a function of an angle off an array antenna bore sight axis;

(c) normalizing the gain of the transmit beam;

(d) evaluating corresponding values of the gain in the cost function to determine if the cost function result exceeds a predetermined limit;

(e) if the predetermined limit is not exceeded, running an optimization program to increment taper coefficient values; and

(f) transferring a last set of taper coefficients to the array antenna for use as input data signals.

4. The method of claim 3, wherein the step of measuring the gain of the transmit beam and the receive beam further comprises:

using an analog taper function with a set of transmit weight and receive weight values which provides the gain for the transmit beam and the gain for the receive beam as normalized gains in decibels as a function of an angle off a bore sight axis for each measured transmit beam gain and receive beam gain.

5. The method of claim 4, further comprising:

generating the transmit beam and receive beam gain values by using executable code to provide values of a Fourier Integral of a taper of the transmit beam and a Fourier Integral of a taper of the receive beam, the values of the Fourier Integrals being normalized.

6. A method for a radar system, comprising:

providing a transmit beam taper function and a receive beam taper function;

initializing the transmit beam taper function with a transmit set of values and the receive beam transmit function with a receive set of values;

normalizing the transmit beam function and the receive beam function to obtain normalized transmit beam and receive beam gain weights that span a predetermined range of angles on either side of an antenna bore sight axis;

using a cost factor function to determine cost factor values and reciprocal cost factor values;

determining if all cost factor values exceed a predetermined number; and

incrementing the transmit beam set of values and the receive beam set of values so that a radar response is minimized in a sidelobe region.

7. The method of claim 6, further comprising:

using a Taper Weighting Calculation Function with a set of transmit beam values and receive beam values to calculate an attenuator transmit beam weights and receive beam weights for each attenuator and transfer the calculated attenuator transmit weights and receive weights to an antenna controller.

8. The method of claim 7, wherein the Taper Weighting Calculation Function is determined by:

A(r)=cos(π

r/D)^N;

where “

r”

is a radial coordinate of any element in an array aperture and N and D are optimized parameters.

9. A system for optimizing transmit beam and receive beam antenna radiation patterns, comprising:

an optimizer engine configured to receive initial estimates of beam weights for a transmit beam and a receive beam; and

a cost function evaluator configured to receive the initial estimates and to apply a cost function to the initial estimates to optimize the beam weights so that a radar response peaks in a main region and is minimized in a sidelobe region;

wherein the cost function uses characteristics of both the receive beam and the transmit beam.

10. The system of claim 9, wherein the evaluator is further configured to generate an output that may be fed back to the optimizer engine to further optimize the beam weights.

11. The system of claim 10, wherein the optimizer engine is further configured to pass a refined estimate of beam weights for the transmit beam and the receive beam to the evaluator.

12. The system of claim 9, wherein the optimizer engine and the cost function evaluator comprise a single physical component.