Effective coherent integration method for marine target with micromotion via phase differentiation and radon-Lv´s distribution

Effective detection of marine targets with low observability gives a severe challenge to radar signal processing. The micro-Doppler (m-D) signatures of marine target can provide extra information for non-stationary and time-varying signal analysis. Long-time integration is an effective way to strengthen the m-D signal and improve signal-to-clutter ratio. However, the performances are affected by the range across unit and Doppler frequency migration effects. In this study, m-D characteristics of marine target are studied and a novel representation, i.e. phase differentiation and Radon-Lv´s distribution (PD-RLVD), is proposed to detect the m-D signal to realise the long-time coherent integration. The PD-RLVD can accurately and directly represent the m-D signal in the chirp rate and chirp change domain appearing as obvious peaks. The proposed method is simple not only because it only requires a 2D Fourier transform of the scaled Radon instantaneous auto-correlation function after PD, but also for not introducing any non-physical attributes. Relations between PD-RLVD and other integration methods are introduced as well. Experiments with real data show that the proposed method can achieve higher integration gain, detection probability, and accuracies of motion parameter estimation.