Analysis of the Retrieval Performance of 2-D Ionospheric Irregularity Maps in the Biomass Mission

Abstract

Low-frequency synthetic aperture radar (SAR) images are affected by trans-ionospheric propagation of the radar waves. The 2-D total electron content (TEC) maps can be obtained as a product of the ionospheric corrections, allowing for imaging of ionospheric irregularities at very high resolution and broader coverage compared to other sensing technologies (such as Global Navigation Satellite Systems (GNSS) and ionosondes). We analyze, in this article, the case of the Biomass mission and characterize the errors in the imaging of the ionosphere resulting from the calibration algorithms foreseen for its ground processor prototype: a Faraday rotation (FR)-based and an autofocus (AF) approach. The analysis relies on a turbulent power law Rino model for the perturbation of the ionosphere and the spectral behavior of the calibration algorithms. We also discuss the suitability of both approaches for image correction in different scenarios (varying signal-to-noise ratio (SNR) and geographic location).