Impacts of Systematic Errors on Topographic Parameter Estimation in Multitemporal InSAR: A Quantitative Description

Estimation of surface deformation using synthetic aperture radar interferometry (InSAR) technique requires a precise removal of the topographic phase. Under multitemporal InSAR (MTInSAR) framework, topographic residual raised by differential operation with external Digital Elevation Model (DEM) is usually parameterized and jointly estimated together with deformation model, while the estimation can be distorted by systematic errors (e.g., model bias, baseline error). This letter aims to offer practical guidelines to users of MTInSAR framework concerning these errors and estimation precision. Starting from the generalized model, we derived the error propagation formula to quantitatively indicate how and to what extent the systematic errors degrade the topographic parameter estimation. The formulas validated by simulated tests are expected to be useful for optimal selection of MTInSAR modeling strategies and development of innovative algorithms (e.g., non-parametric estimator) for retrieval of DEM residuals from MTInSAR measurements.