Real-time SAR processing of ice-sounding data integrated with mitigation of RFI signals
In this paper, we propose an approach to integrate the radio-frequency interference (RFI) mitigation technique into a real-time synthetic aperture radar (SAR) imaging algorithm applied to very high frequency (VHF) ice-sounding data that produces swath measurements of ice sheet surface topography, ice thickness, and radar reflectivity of both Internal Reflecting Horizons (IRHs) and bedrock of the ice sheet. According to the proposal, the RFI suppression method-an adaptive line enhancer (ALE) controlled by the normalized least mean square (NLMS) , is incorporated into the real-time imaging algorithm named modified Planar Subarray Processing (PSAP) algorithm based on inverse scaled Fourier transform (ISFT). The approach is tested successfully on real data recorded over Chinese Kunlun Station during the 29th Chinese Antarctic Research Expedition (CHINARE 29). The experimental result indicates that the narrowband RFI could be subtracted from the desired chirp signal return during the imaging processing, and the computational efficiency of the imaging processing is preserved.