Multichannel SAR imaging using wavefront reconstruction

Abstract

The combination of phased arrays with Synthetic Aperture Radar (SAR), ie. multichannel SAR offers many benefits such as improved ambiguity suppression for Moving Target Indication (MTI) and imaging large swaths [1]-[2], improved Signal-Noise-Ratio (SNR) [3] and the potential to suppress spatial jammers by use of Space Time Adaptive Processing (STAP) [4]. Classical SAR imaging is based on analogue/optical techniques and includes polar format and range-doppler based imaging. More precise imaging algorithms are based on wavefront reconstruction [5], and offer the potential for imaging with greater accuracy. Soumekh [6], has summarised a number of these including spatial MF interpolation, range stacking and time domain correlation. While multichannel SAR imaging has been addressed by [4], there has been no comprehensive study on how different wavefront reconstruction algorithms can be implemented for focussing multichannel data. This work extends these three SAR wavefront reconstruction algorithms to include multiple transmit and receive antennas and provides a quantitative comparison of their Point Spread Functions (PSF).