Ground Moving Target Imaging (GMTIm) Algorithm in OFDM SAR Based on First-Order Keystone Transform

The use of Orthogonal Frequency Division Multiplexing (OFDM) waveform in place of Linear Frequency Modulation (LFM) signal is one of the latest topics in the field of Synthetic Aperture Radar (SAR) imaging. The advantages of imaging by this technique include resistance to certain types of radar jamming techniques, reduced ambiguity in Doppler spectrum with an increase in the number of sub-bands, and extraction of target phase history based on phase approximation of all OFDM subcarriers. In conventional SAR imaging algorithms, it is assumed that the targets are stationary in the imaging zone as these algorithms do not have the required efficiency to image moving targets, leading to blurred images and high Integrated Side Lobe Ratio (ISLR). To circumvent these problems, there is a requirement of designing appropriate imaging algorithms, keeping in mind the important issues related to the moving targets in the imaging zone. Thus, in this study, we propose the implementation of the OFDM waveform for imaging moving targets alongside the first-order keystone transform to solve the above-mentioned problems.