Moving target integration by exponentially weighted recursive RFT

摘要

The Radon-Fourier transform (RFT) can effectively overcome the coupling between the range cell migration effect and Doppler modulation by jointly searching along range and velocity dimension for the moving target, which depends on envelope alignment and additional Doppler phase compensation. However, as to the conventional RFT method, it needs to wait until the whole coherent processing interval (CPI) is over before performing RFT integration, which is not flexible. Also, all echo data in the CPI takes the same weight. In this study, the weight of echo data has been generalised by the straightforward idea that new data should occupy more weight, while old echo data should take less. Thus, a novel method, named exponentially weighted recursive RFT (RRFT) has been proposed to realise RFT integration recursively. The computations can be started before all the data has been collected. The signal-to-noise ratio level of the echo signal is being improved during the iteration. The equivalent total coherent integration time and velocity resolution have been presented. The theoretical analysis shows that the computational complexity is of the same order as that of RFT. Finally, some numerical results are provided to validate the proposed method.