Technique for processing interference-contaminated radar energy

• US 5,442,365 A
• Filed: 09/02/1975
• Issued: 08/15/1995
• Est. Priority Date: 09/02/1975
• Status: Expired due to Term

• Current Assignee: Bernard L. Lewis, Frank F. Kretschmer Jr
• Original Assignee: Bernard L. Lewis, Frank F. Kretschmer Jr
• Inventors: Lewis, Bernard L., Kretschmer, Frank F. Jr.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US05/609,752
• Time in Patent Office: 7,287 Days
• Field of Search: 343/18 E, 343/100 LE, 343/7 A, 325/371, 325/474, 325/475, 342/382, 342/381, 342/19
• US Class Current: 342/381
• 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
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: H04K 3/224 with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer

Abstract

A technique for improving sidelobe canceller performance by blocking the canceller output signal upon sensing reduced main channel interference accompanied by an increased sidelobe canceller output. Two signal processing networks form the difference between successive output signals from a radar antenna and sidelobe canceller respectively. The difference signals are multiplied together and the product used to control passage and preclude utilization of the canceller output signal when reduced jamming interference occurs.

Claims

1. A method of preventing utilization by a radar system of a signal V_o.sbsb.a from a sidelobe canceller during the period that a signal V_R at a radar antenna experiences reduced effective jamming signal interference while a jamming signal is simultaneously present at the output of an associated sidelobe canceller auxiliary antenna comprising the steps of:

sensing successive canceller output signals V_o.sbsb.n, V_o.sbsb.n-1 ;

forming a first difference signal (V_o.sbsb.n -V_o.sbsb.n-1) which may be positive or negative;

sensing successive main channel radar signals V_R.sbsb.n-1, V_R.sbsb.n ;

forming a second difference signal (V_R.sbsb.n-1 -V_R.sbsb.n) which may be positive or negative;

forming a product signal by multiplying said first difference signal by said second difference signal;

interrupting receipt by the radar system of the sidelobe canceller output signal whenever said product signal is negative.

2. A system for preventing utilization by a radar system of a signal V_o from a sidelobe canceller to which a radar is coupled during the period that a signal V_R at the radar antenna experiences reduced effective jamming signal interference while a jamming signal is simultaneously present at the output of an associated sidelobe canceller auxiliary antenna comprising:

means for sensing sequential values V_R.sbsb.n-1, V_R.sbsb.n of the radar signal V_R ;

means for forming a first difference signal V_R.sbsb.n-1 -V_R.sbsb.n which may be positive or negative;

means for sensing sequential values V_o.sbsb.n-1, V_o.sbsb.n of the output sidelobe canceller signal V_o ;

means for forming a second difference signal V_o.sbsb.n-1 -V_o.sbsb.n which may be positive or negative;

means for multiplying said first different signal by said second difference signal thereby producing a product signal;

means for disconnecting the output of said signal canceller from said radar system when said product signal is negative.