Adaptive radar signal processor for the detection of useful echo and the cancellation of clutter

• US 4,719,466 A
• Filed: 12/13/1984
• Issued: 01/12/1988
• Est. Priority Date: 12/13/1983
• Status: Expired due to Fees

• Current Assignee: Alenia Aeritalia & Selenia SpA (Leonardo S.p.A.)
• Original Assignee: Selenia-Industrie Elettroniche Associate SPA
• Inventors: Studer, Flavio A., Farina, Alfonso
• Primary Examiner(s): Tubbesing, T. H.
• Assistant Examiner(s): Gregory, Bernarr Earl
• Application Number:
  US06/681,497
• Time in Patent Office: 1,125 Days
• Field of Search: 343/5 CE, 343/5 CF, 343/18 E, 343/380, 343/381, 343/382, 343/383, 343/384, 343/7.7, 342/17, 342/159-164, 342/189, 342/194, 342/380, 342/382-384, 342/89, 364/516, 364/517, 364/574, 364/724
• US Class Current: 342/159
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242

Abstract

Adaptive radar signal processor apt to detect the useful echo in the presence of an additive disturbance made up of clutter and noise, through which the disturbance can be cancelled and the useful signal can be enhanced by means of the synthesis of a filter, adapted to the useful signal, which rejects the disturbance spectrum frequency components by adapting itself in real time to its variations.

Claims

1. An adaptive radar signal processor for the detection of a useful signal of received signals in the presence of an additive disturbance in the form of clutter and noise comprising a modular structure of decorrelators and of a series of power normalizers through which parameters of said processor can be modified automatically as a function of the characteristics of the disturbance and of the useful signal, each of said decorrelators having a lattice structure comprising:

calculating means for calculating the complex conjugate function of expected useful signals forming complex conjugate signals;

a first multiplier coupled to an output of said calculating means for multiplying said complex conjugate signals with said expected useful signals;

a second multiplier coupled to said calculating means for multiplying said complex conjugate signals with said received signals;

first integrating means coupled to said first multiplier;

second integrating means coupled to said first multiplier;

a third multiplier coupled to said first integrator for multiplying an output of said first integrator with said received signals;

a fourth multiplier coupled to said second integrator for multiplying an output of said second integrator with said expected useful signals; and

summing means coupled to said third multiplier and said fourth multiplier for adding outputs of said third multiplier and said fourth multiplier forming power and correlation estimate signals whereby said power and said correlation estimate signals are utilized both for power normalization and for linear processing of samples of an expected target signal.

2. An adaptive radar signal processor for the detection of a useful signal of received signals in the presence of an additive disturbance in the form of clutter and noise comprising a modular structure of decorrelators and of a series of power normalizers through which parameters of said processor can be modified automatically as a function of the characteristics of the disturbance and of the useful signal, with an entirely transversed configuration devoid of feedback, and each of said decorrelators having a lattice structure comprising:

calculating means for calculating the complex conjugate function of expected useful signals forming complex conjugate signals;

a first multiplier coupled to an output of said calculating means for multiplying said complex conjugate signals with said expected useful signals;

a second multiplier coupled to said calculating means for multiplying said complex conjugate signals with said received signals;

first integrating means coupled to said first multiplier;

second integrating means coupled to said first multiplier;

a third multiplier coupled to said first integrator for multiplying an output of said first integrator with said received signals;

a fourth multiplier coupled to said second integrator for multiplying an output of said second integrator with said expected useful signals; and

summing means coupled to said third multiplier and said fourth multiplier for adding outputs of said third multiplier and said fourth multiplier forming power and correlation estimate signals wherein said power and said correlation estimate signals are utilized both for power normalization and for linear processing of samples of an expected target signal.