APS Estimation and Modeling for Radar Interferometry

R. F. Hanssen(1) , A. Ferretti(2) , M. Bianchi(2) , and A. Elawar(1)

(1) Delft University of Technology, Kluyverweg 1, 2629HS Delft, Netherlands
(2) Tele-Rilevamento Europa, Via Vittoria Colonna 7, 20149 Milano, Italy

Abstract

Estimating the atmospheric phase screen (APS) for repeat-pass radar interferometry is one of the key steps in estimating parameters such as surface deformation and topography. Since the spatial covariance function of the atmospheric phase screen can have similar characteristics as that of surface deformation or (unmodeled) topography, unambiguous estimation of the APS can cumbersome. Current methodologies such as permanent scatterer (PS) interferometry improve APS estimation significantly by exploiting the fast temporal decorrelation of the atmospheric error signal. Nevertheless, attributing the interferometric phase signal to either atmosphere or surface deformation is subject to the a priori knowledge of the (stochastic) behavior of atmospheric phase screen, mainly the water vapor distribution.

In this study, we compare two independent data sources for APS estimation and use these to propose and validate a new stochastic model based on the Matern class of covariance functions. The first data source is based on previous PS estimations, for which APS is a side product. Parametrization of the spatial stochastic behavior of these APS estimations can can provide an independent quality assessment of the APS, which may provide independent support of the estimated deformation fields. The second analysis is based on instantaneous coincident MERIS-ASAR acquisitions. Under favorable conditions, the Medium Range Image Spectrometer data can be used to estimate integrated water vapor at the same time as the ASAR radar acquisitions. We comment on the quality of these APS estimations and their use for independent APS estimation.

 

Workshop presentation

 

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