Antenna beam alignment for a spaceborne dual-antenna single-pass interferometric SAR

To achieve excellent interferometric performance, spaceborne dual-antenna single-pass interferometric SAR is better than the repeat-pass configuration. However, the antenna beam alignment is crucial to the interferometric correlation. The antenna beam alignment is designed to consist of three steps: coarse mechanical adjustment, fine electronic steering and beam pointing maintenance. Fine beam alignment in azimuth is discussed in this paper, and an antenna beam alignment strategy is presented: a novel Doppler centroid estimation algorithm is proposed to measure antenna beam pointing, as well as a LMS-based prediction method to steer antenna beam adaptively. Finally, simulation results are used to demonstrate this strategy is reliable and precise for onboard beam steering.