Efficient Coherent Integration Based on RDT-SCFT-KT for Manoeuvring Target With Doppler Ambiguity

Range migration (RM), Doppler frequency migration (DFM) and Doppler ambiguity, arising from high-speed manoeuvre of target, render moving target detection particularly difficult. In this paper, an efficient method based on reversal decoupling transform (RDT), scaled Fourier transform (SCFT) and keystone transform (KT), that is, RDT-SCFT-KT, is proposed for effective long-time coherent integration (LTCI) of an accelerated manoeuvring target with Doppler ambiguity. More specifically, an efficient RDT is performed to tackle range curvature and some other unnecessary terms. After that, the scaled inverse Fourier transform (SCIFT) and SCFT are successively introduced to handle the linear RM and DFM, thereby realising two-dimensional (2-D) energy integration. Besides, velocity and acceleration with respect to target could be acquired by the aid of peak detection. With the compensation associated with the obtained parameters, a linear and nonsearching approach involving the KT is developed to efficiently attain the final energy focusing and the remaining target parameters (i.e., range and unambiguous velocity). Given the above, the proposed RDT-SCFT-KT method could achieve LTCI for accelerated manoeuvring target and exhibits low computational complexity without requiring parameter searching process. Meanwhile, it remains effective for Doppler ambiguity (including velocity ambiguity and Doppler spectrum ambiguity) and offers complete motion parameters. Besides, the final energy integration is a linear transform process, which facilitates multi-target processing. The efficacy of the RDT-SCFT-KT integration approach is substantiated through numerical experiments.