A Novel Beam-Steering Method for Spaceborne Interferometric Synthetic Aperture Radar Altimeter

The Spaceborne altimeter based on Interferometric Synthetic Aperture Radar (InSAR) can achieve high-resolution, wide-swath and high-accuracy height measurement of sea surface. The beam steering of the SAR systems in orbit is designed to access SAR images with the same noise equivalent sigma zero (NESZ) for near-range and far-range observation areas. However, for InSAR altimeters, the conventional method would result in the height accuracy of near-range areas much higher than the far-range ones. To achieve the required height accuracy in far-range areas, the SAR systems have to improve the transmission power or increase the size of antenna, improving the complexity in system designation. In this paper, a novel beam-steering method for spaceborne InSAR altimeters is proposed. The beam-steering angle is optimized according to the height accuracy in the whole scene. The performance of the proposed method over the conventional method is validated by the simulation.