An Investigation on Atmospheric Effects in Airborne Interferometric SAR data

Abstract

The results of an experiment on atmospheric effects in interferometric SAR data are presented. The main purpose of the experiment was to investigate on the influence of the troposphere on airborne synthetic aperture radar measurements, acquired by DLR’s experimental E-SAR system. The analysed data was acquired at L-band. The main idea behind the experiment is to collect data sets at different atmospheric conditions and to compare the measurements by performing a differential interferometric analysis. The main difference between atmospheric conditions on “Day-One” and “Day-Two” of acquisition was a cloud layer between sensor and illuminated surface, reaching from 750 to 1500 m above sea-level (msl). The sensor altitude was about 4000 m (msl). The test site is located at 580 m (msl). The results of the experiment will be highlighted and an interpretation of the observed differential effects will be given. In a first investigation [1] no pronounced indication of atmospheric effects in L-band interferograms was found. In the paper here proposed, two different techniques, multisquint [2] and weighted phase curvature autofocus (WPCA) [3], are applied to accurately mitigate residual motion errors allowing a better interpretation of any possible atmospheric effects. [1] A. Danklmayer and K.A.C. de Macedo. An experiment on atmospheric effects in airborne interferometric SAR data, International Symposion on Antennas and Propagation (ISAP), Toki Messe, Niigata, Japan, 2007. [2] Prats, P. and Reigber, A. and Mallorqui, J. J.. Interpolation-Free Coregistration and Phase-Correction of Airborne SAR Interferograms. IEEE Geoscience and Remote Sensing Letters, vol. 1, no. 3, pp. 188-191, Jul. 2004. [3] K.A.C de Macedo, R. Scheiber and A. Moreira. An autofocus approach for residual motion errors with application to airborne repeat-pass SAR interferometry. IEEE Transactions on Geoscience and Remote Sensing, under review.