Localized interference nulling preprocessor

• US 5,841,395 A
• Filed: 09/12/1997
• Issued: 11/24/1998
• Est. Priority Date: 09/12/1997
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Simone, Joseph D.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US08/928,563
• Time in Patent Office: 438 Days
• Field of Search: 342/196, 342/157, 342/158, 342/159, 342/162, 342/373, 364/726.01, 364/726.02, 370/210, 702/77
• US Class Current: 342/196
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242

Abstract

A localized interference nulling preprocessor for a Fast Fourier Transform (FFT) or a Butler matrix system includes a means for forming a dot product of a signal vector and each of the preprocessed eigen vectors of the virtual interference covariance matrix of a predetermined localized interference, means for scaling the conjugate of the principal eigen vectors by the dot product, and means for subtracting from the signal vector the product of each dot product and conjugate of principal eigen vectors to generate a preprocess signal vector modified to produce a localized nulling of predetermined localized interference by a Fast Fourier Transform (FFT) or Butler matrix system.

Claims

1. A localized interference nulling preprocessor for a Fast Fourier Transform (FFT) system, comprising:

means for forming the dot product of the signal vector and each of the preprocessed eigen vectors of the virtual interference covariance matrix of a predetermined localized interference;

means for scaling the conjugate of said principal eigen vectors by said dot product; and

means for subtracting from the signal vector the product of each said dot product and conjugate of said principal eigen vectors to generate a preprocessed signal vector modified to produce a localized nulling of said predetermined localized interference by a Fast Fourier Transform (FFT) system.

2. The localized interference nulling preprocessor for a Fast Fourier Transform (FFT) system wherein said means for scaling includes multiplier means.

3. A localized interference nulling preprocessor for a Butler matrix system, comprising:

means for forming the dot product of the signal vector and each of the preprocessed eigen vectors of the virtual interference covariance matrix of a predetermined localized interference;

means for scaling the conjugate of said principal eigen vectors by said dot product; and

means for subtracting from the signal vector the product of each said dot product and conjugate of said principal eigen vectors to generate a preprocessed signal vector modified to produce a localized nulling of said predetermined localized interference by a Butler matrix system.

4. The localized interference nulling preprocessor for a Butler matrix system wherein said means for scaling includes multiplier means.