Measurement of ionospheric Faraday rotation in simulated and real spaceborne SAR data

摘要

The influence of the atmosphere on a frequencymodulated\udelectromagnetic wave traversing the ionosphere is becoming increasingly important for recent and upcoming lowfrequency\udand wide-bandwidth spaceborne synthetic aperture radar (SAR) systems. The ionized ionosphere induces Faraday\udrotation (FR) at these frequencies that affects radar polarimetry and causes signal path delays resulting in a reduced range resolution.\udThe work at hand introduces a simulation model of SAR\udsignals passing through the atmosphere, including both frequencydependent FR and path delays. Based on simulation results from this model [proven with real Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (PALSAR) data], estimation of FR in quad-polarized SAR data using the given approach is shown for raw, range-compressed, and focused radar images. Path delays and signal chirp bandwidth effects are considered.\udInvestigations discuss the suitability of raw and compressed\uddata versus combination of total electron content maps with the Earth’s magnetic field for FR estimation and deduced from a large number of analyzed PALSAR data sets.