Azimuth Phase Center Adaptive Adjustment on Transmit/Receive for Azimuth Uniform Sampling in HRWS SAR

The spaceborne multi-channel Synthetic Aperture Radar (SAR) systems, having the high-resolution wide-swath (HRWS) imaging capacity, are proving to be an extremely useful surveillance tool for remote sensing of the earth surface. However, azimuth nonuniform sampling will be generated, if the pulse repetition frequency (PRF) is not chosen as the optimum value. Although the phenomenon of azimuth non-uniform sampling could be reconstructed by azimuth multichannel reconstruction algorithms, the inverse character of such reconstruction algorithms might result in a degraded SAR system performance, particularly if the operated PRF strongly deviates from the optimum value. In this paper, an innovative azimuth phase center adaptive adjustment on transmit/receive (TX/RX) is proposed to generate uniform azimuth sampling even if the optimum PRF value is not taken. The phased array antenna architecture, consisting of a great number of individually controllable radiating elements, allows for adjusting the position of receive/transmit phase center in order to obtain uniform sampling. Simulation experiments verify the effect of the proposed system to compensate non-uniform sampling.