Cascaded adaptive loops

• US 4,439,770 A
• Filed: 06/23/1976
• Issued: 03/27/1984
• Est. Priority Date: 06/23/1976
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Lewis, Bernard L., Kretschmer, Frank F. Jr.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US05/696,620
• Time in Patent Office: 2,834 Days
• Field of Search: 343/100 LE, 343/381
• 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: H01Q 3/2611 Means for null steering; Adaptive interference nulling

Abstract

A sidelobe-canceller system for cancelling jamming interference signals f a radar signal includes serially cascaded cancellation channels utilizing preprocessing cancellers and main-channel cancellers. The last serially cascaded cancellation channel includes terminal preprocessing cancellers and terminal main-channel cancellers. The preprocessing is improved by the use of AGC circuits connected one each between the terminal preprocessing cancellers and terminal main-channel cancellers to stabilize the gain of the terminal main-channel cancellers, thus improving the cancellation ratio and transient response of the system.

Claims

1. A sidelobe canceller system utilizing preprocessing to cancel multiple jamming interference signals, said system including a plurality of serially cascaded cancellation channels, said system comprising:

main-radar antenna means for receiving a radar signal;

a plurality of auxiliary antenna means for receiving signals from a jamming interference environment, one of said auxiliary antenna means constituting a first auxiliary antenna means;

a plurality of serially connected cancellation channels each said cancellation channel including;

means for receiving and preprocessing the outputs of said plurality of auxiliary antenna means to decorrelate the outputs of said plurality of auxiliary antenna means;

a plurality of serially connected main channel cancellers, the first main channel canceller of the first cancellation channel receiving the output of said first auxiliary antenna means and said main radar antenna and the first serial main channel canceller of the remaining cancellation channels receiving the outputs of said first auxiliary antenna means and the output of the last main channel canceller of the proceeding cancellation channel, the remainder of said main channel cancellers of each cancellation channel receiving decorrelated auxiliary antenna outputs from said means for receiving and processing; and

a terminal cancellation channel including;

terminal means for receiving and preprocessing the outputs of said plurality of auxiliary antenna means to decorrelate the outputs of said plurality of auxiliary antenna means;

a plurality of serially connected, terminal main channel cancellers, the first serial terminal main channel canceller receiving the output of said first auxiliary antenna means and the output of the last main channel canceller of the last serial cancellation channel, the remainder of said terminal main channel cancellers receiving the auxiliary antenna outputs from said means for receiving and preprocessing; and

a plurality of AGC means, each of which receives one of said auxiliary antenna outputs from said terminal means for receiving and preprocessing and provides an output to one of said terminal main channel cancellers.

2. A sidelobe-canceller system utilizing preprocessing to cancel multiple jamming interference signals, which comprises:

main-radar antenna means for receiving a radar signal;

a plurality of auxiliary antenna means for receiving signals from a jamming interference environment, one said auxiliary antenna means constituting a first auxiliary antenna means;

a plurality of sequentially connected terminal preprocessing cancellers, the first of said sequence of cancellers receiving the output of said first auxiliary antenna means and the output of one other said plurality of auxiliary means, the remaining terminal preprocessing cancellers of said sequence each receiving the output of the preceeding sequential terminal preprocessing canceller and the output of one of said auxiliary antenna means;

a first main-channel canceller receiving the output of said main-radar antenna means and the output of said first auxiliary antenna means;

a plurality of serially connected, terminal main-channel cancellers, the first canceller of said series receiving the output of said first main-channel canceller, each said terminal main-channel cancellers receiving the output of one of said plurality of terminal preprocessing cancellers; and

AGC means connected one each between said terminal preprocessing cancellers and said terminal main-channel cancellers for controlling the amplitudes of the signals transferred between said terminal preprocessing cancellers and said terminal main-channel cancellers.