Heterogeneous performance analysis of the new model of CFAR detectors for partially-correlated χ 2 -targets

Abstract

To mitigate the deleterious effects of clutter and jammer, modern radars have adopted adaptive processing techniques such as constant false alarm rate (CFAR) detectors which are widely used to prevent clutter and noise interference from saturating the radar's display and preventing targets from being obscured. This paper concerns with the detection analysis of the novel version of CFAR schemes (cell-averaging generalized trimmed-mean, CA GTM) in the presence of additional outlying targets other than the target under research. The spurious targets as well as the tested one are assumed to be fluctuating in accordance with the χ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -model with two-degrees of freedom. In this situation, the processor performance is enclosed by the swerling models (SWI and SWII). Between these bounds, there is an important class of target fluctuation which is known as moderately fluctuating targets. The detection of this class has many practical applications. Structure of the CA GTM detector is described briefly. Detection performances for optimal, CA TM, CA, trimmed-mean (TM) and ordered-statistic (OS) CFAR strategies have been analyzed and compared for desired probability of false alarm and determined size of the reference window. False alarm rate performance of these processors has been evaluated for different strengths of interfering signal and the effect of correlation among the target returns on the detection and false alarm performances has also been studied. Our numerical results show that, with a proper choice of trimming parameters, the novel model CA TM presents an ideal detection performance outweighing that of the Neyman-Pearson detector on condition that the tested target obeys the SWII model in its fluctuation. Although the new models CA OS and CA TM can be treated as special cases of the CA GTM algorithm, their multi-target performance is modest even it has an enhancement relative to that of the classical CA scheme. Additionally, they fail to maintain the false alarm rate constant when the operating environment is of type target multiplicity. Moreover, the non-coherent integration of M pulses ameliorates the processor performance either it operates in homogeneous or multi-target environment.