Range-spread target detector via coherent energy accumulation and block thresholding denoising

A range-spread target (RST) detector is proposed for wideband radar. The detector, referred to as a conjugate multiplication and block thresholding (CMBT) detector, is simple for implementation in existing radar systems and has the advantage of minor calculation. First, the target energy of adjacent stretched echoes is coherently accumulated via conjugate multiplication and Fourier transform operations. It is noted that conjugate multiplication of two complex Gaussian distributed noise is complex double Gaussian distributed, leading to a signal to noise ratio (SNR) loss. Subsequently, considering the sparsity and clustering characteristics of the conjugate multiplication amplitude spectrum (CMAS), the block thresholding method is adopted for denoising, where the noise and cross-terms are adaptively smoothed, and the signal terms can be basically preserved. Finally, numerical simulation results for both synthetic and real radar data validate the effectiveness of the proposed detector, comparing with the conventional integration detector (ID), the spatial scattering density (SSD) detector, and waveform entropy (WE) and waveform contrast (WC) based detectors.