Parameter estimation of LFM signals based on NAT functions in impulsive noise

Abstract

To address the problem of performance degradation or even failure of traditional linear frequency modulation signal (LFM) parameter estimation methods under impulsive noise, this paper constructs two new nonlinear amplitude transformation (NAT) functions, namely the attenuation-NAT(A-NAT) function and the increasing bounded-NAT(IB-NAT) function. The derivation proves that the second-order moments of the large amplitude pulse samples are bounded by A-NAT or IB-NAT. Moreover, only the amplitude of the LFM signal changes after the proposed transformation, and the phase information remains unchanged. Perform Lv's distribution (LVD) analysis on the noisy signal after NAT transformation, and the parameter estimates of the LFM signal could be obtained based on the peak coordinates. Experimental results show that the proposed methods are robust, and they do not need the prior information of the impulsive noise, and can still accurately extract the signal parameter information even under strong impulse noise conditions.