Estimation of initial phase offset in real-time for airborne dual-antenna InSAR system

To obtain DEM in real-time by the unwrapped phase in InSAR system, the initial phase offset is also extraordinary important factor, besides the real-time baseline parameters and time delay errors. In traditional interferometric processing, it can be estimated by the Ground Control Points. However, it is so time-consuming and complex that can´t be used in the real-time InSAR system. So the factors that impact the phase offset are analyzed, and the algorithm of estimating initial phase offset in real-time based on external DEM with coarse precision is presented in this paper. In the algorithm, the coarse DEM data of SRTM is used as the reference, and together with the tested area data by the appointed means, the phase offset is estimated in real-time, then DEM is reconstructed in real-time. The processed result for the real InSAR data indicates that the algorithm has high DEM precision, and the real-time demand can be satisfied.