The adaptation of recursive notch filters

Abstract

Background. The object of the study is an adaptive notch filters (ANF) of a recursive type, designed to isolate radar signals of moving targets against the background of passive interference with a priori unknown spectral-correlation characteristics. The puspose of the work is the synthesis and analysis of recursive harps of a tunable structure. Materials and methods. The principles of construction and structural schemes of recursive harps are considered according to their system function with varying degrees of a priori uncertainty of the spectral-correlation characteristics of passive interference. Results. ANFs with complex weighting coefficients are proposed, the simplification of which is achieved by using autocompensators of the Doppler phase of passive interference and its subsequent rejection by a filter with real weighting coefficients. The principle of adaptation according to the estimated values of the criterion of the effectiveness of the rejection is proposed, which does not require an assessment of the form of the correlation function of the incoming interference. Conclusions. Synthesized recursive-type ANFs allow, by restructuring the structure and adaptive adjustment of parameters, to achieve, under conditions of a priori uncertainty, the characteristics of passive interference of a given or limit value of their suppression.

Keywords

• autocompensation
• adaptation
• a priori uncertainty
• doppler phase
• training sample
• passive interference
• rejection filter