Research Of Insar Baseline Estimation And The Effects On The Flat Phase

InSAR is based on satellite orbit data or baseline parameters, using high sensitivecharacteristics of the phase signal interference to extraction and separation of the usefulinformation and widely used in extraction surface elevation and ground surface deformation.Will the same area of two radar images corresponding pixel conjugate multiplication can getinterferometric phase diagram. Interferometric phase is stripe with the terrain and deformationinformation, so the focus of the InSAR data processing analysis is interferometric phase,which consisits of the flat phase and terrain phase composition. Remove the terrain preciselevel flat phase is the key to achieving a more accurate information. And baselin estimate isthe key parameters calculated the ground phase, so the importance of the baseline to theground and the influence of phase is obvious.In this paper,the author briefly summarizes the development history and the basicinterference measuring principle of InSAR. Analysed their advantages and disadvantagesthrough the realization of several existing baseline estimation algorithm, and improved thelinear component fitting contrapose the most commonly used in the calculation based on trackthe algorithm of the baseline, realized the equation to substitute for a fixed value algorithm,and verified its validity. Analysed the influence of baseline to the level ground phase, and alsoreminded researchers that the main error source of baseline to DEM is computational errorpropagation of level ground phase to DEM.This article mainly includes：1) Introduction of InSAR measuring basic theoretical knowledge. This part emphasizesthe basic principle of InSAR and summarizes the InSAR data processing flow. The basicprinciple mainly describes the interference measuring work mode and the principle which canbe interference measured.2) Improvement of InSAR baseline estimate.This part is the key point of the paper,which introduces the necessity of the baseline estimate, describes the existing six algorithms,and in order to improve the disadvantages of using tracks to estimate baseline, I use a newmethod that every400line calculate a baseline and improve linear fitting.3) Confirmation of the accuracy of the improved algorithm.This part test and verify theproved algorithm of baseline estimate, compared the calculation of the results with thecommercial software GAMMA which has a higher precision, proved the improved algorithmis effective.4) Analysis the influence of the baseline to the level ground phase. This part analysis theinfluence of the baseline to the level ground phase from the theory, the simulation and the perspective of experimental validation, and enforce that according to the process that fromraising a question, simulation and analysis to verifying the question.Finally, the author puts forward the still existing problems in this paper and prospects thedevelopment trend of the baseline calculation.