Research On Ionospheric Error Calibration And PS Sequential Processing For Spaceborne D-InSAR

The ionospheric error correction and the sequential processing of long time series differential interference are the two key technical problems of spaceborne differential interferometric synthetic aperture radar(D-InSAR)technology.In this paper,a D-InSAR ionospheric error correction method based on spatial selection and a sequential processing method based on permanent scatterers technique of differential synthetic aperture radar interferometry(PS-InSAR)for candidate point extraction and network reconfiguration are proposed respectively.The research of ionospheric error correction is focused on low-band spaceborne SAR system.The influence of ionosphere on D-InSAR is analyzed.It is pointed out that the interferometric phase shift is the main factor to introduce the deformation measurement error.Aiming at eliminating the drawbacks of the traditional spectral slicing method,such as poor robustness,susceptibility to data processing and SAR image de-coherence error,we propose an optimization estimation method based on spatial selection.Further more,the correction method of D-InSAR ionospheric error is proposed.Experimental results verify the effectiveness of the method.In order to solve the problem that the traditional PS-InSAR processing efficiency is difficult to adapt to the trend of quasi-real-time deformation monitoring,the sequential processing method based on permanent scatterers technique analyzes the candidate points extraction and network construction solution from two aspects: PS candidate point extraction and PS network construction solution.Thus we propose a solution to the sequential processing.In the face of the continuous introduction of massive image data,with the prior processing results as a priori information to guide the processing,this method don't need to repeat all the data for bulk calculation.The experimental results of sequential processing and traditional batch processing of 21 measured data show that the method can greatly improve the efficiency while guaranteeing the processing precision.Our research provides necessary technical exploration and some theoretical support for the continuous development of on-board D-InSAR technology to the high precision and high-time surface deformation measurement.