A study on smearing due to ionospheric phase scintillation in SAR data

Abstract

Spaceborne synthetic aperture radar (SAR) data suffer from scintillation due to changes in the signal path when travelling through the dispersive ionosphere. During data collection, scintillation translates into phase noise in the received signals, which in turn leads to smearing in the resulting image. This article examines ways of reducing ionosphere-induced smearing in high-resolution spotlight SAR data. In this article, several existing techniques are reviewed and one technique is tested using simulated spotlight data with ionospheric phase noise. The results show that the existing techniques are ineffective in correcting spatially varying ionospheric phase noise. Hence, a 2D phase reconstruction and compensation technique is developed, which results in a 10% reduction in the main lobe in simulated data. This technique is also demonstrated to sharpen images using measured data obtained from the TerraSAR-X satellite mission.

Acknowledgement

We thank the German Aerospace Center (DLR) for the TSX data used in this article, which were obtained through an accepted AO LAN0271.