Two-Antenna SAR With Waveform Diversity for Ground Moving Target Indication

Abstract

Along-track interferometry (ATI) and displaced phase center antenna (DPCA) are two representative synthetic aperture radar (SAR) ground moving target indication (GMTI) techniques. However, the former is a clutter-limited detector, whereas the latter is a noise-limited detector. In this letter, we propose a two-antenna SAR with waveform diversity for GMTI. The two antennas placed in the azimuth dimension simultaneously transmit two orthogonal waveforms, namely, the up-and down-chirp waveforms. In doing so, four independent transmit-receive channels are obtained for the receiver, and thus, an efficient GMTI is developed by cooperatively utilizing the ATI GMTI and DPCA GMTI processing techniques. This method first uses the DPCA technique to cancel clutter and then the ATI technique to suppress noise. Next, the fractional Fourier transform is employed to estimate the Doppler parameters and corresponding reference filters are designed to focus the moving targets. The proposed approach cooperatively utilizes the advantages of ATI and DPCA GMTI techniques and overcomes their disadvantages. It does not prerequire knowledge of the target's across-track velocity. The effectiveness is verified by simulation results.Index Terms-Along-track interferometry (ATI), displaced phase center antenna (DPCA), ground moving target indication (GMTI), Synthetic aperture radar (SAR), waveform diversity.

Parameter Estimation of a Ground Moving Target Using Image Sharpness Optimization

“…Traditionally, after clutter suppression and moving target detection in the image domain, the motion parameter of the target can be estimated using ATI [16,17] and DPCA [18,19] techniques.…”