Ionosphere Perturbation Effects in Repeated Orbits SAR Interferometry

Abstract:
Ionospheric effects produce image distortions which may be mixed up with true surface dynamics measured in repeated orbits interferometry scheme. We discuss different ways to estimate the phase fluctuations because of ionosphere irregularities in order to use the phase history of perturbations estimated at the subsequent stage of more precise SAR image focusing and to remove therefore the azimuth displacements of image segments. SAR image autofocusing technique like as phase gradient autofocus (PGA) or subapertures correlation technique seem to us to be most promising for accurate image synthesis both for interferometric applications and more reliable SAR data geocoding.