Ionosphere impact and corrections for low frequency radars

To enable accurate microwave low-frequency (VHF to L-band) radar products by a proper understanding, assessment and correction of the impact of ionosphere on the measurements  

The use of low microwave frequencies for radars is key.: It enables radar signals from sub-surface sounders to penetrate deep under the Earth surface, it allows minimised temporal decorrelation in Synthetic Aperture Radars observations (e.g L-band SAR) and to generate high quality interferometric products, it opens up the bistatic use of signals of opportunity due to the presence of L-band navigation signals. However these VHF to L-band signals are highly sensitive to the state of the ionosphere which can create strong perturbations, or even block the signal.   As the ionosphere strongly varies, and exhibits particularly complex behaviour at high latitudes it is critical to precisely assess its impact and derive mitigation techniques.   This activity will consolidate the understanding of the impact of ionosphere on these measurement techniques, derive quantitative performance degradation figures and to develop and test mitigation techniques, with a focus on high latitude regions. This will contribute to feasibility assessment and performance improvement of the related mission concepts.   This activity encompasses the following tasks: - review of the ionosphere spatio-temporal characteristics and impact on the measurement techniques (altimeter and sounder, polarimetric and interferometric SAR, GNSS-R altimetry); - assessment of the impact of ionosphere on observation quality (in a statistical sense) for a subset of mission concepts of interest; - development of mitigation techniques that could be applied to these mission concepts; - test and performance evaluation of these techniques for selected scenarios.   In addition to the final report, the activity will deliver algorithmic description of the mitigation techniques and datasets corresponding to the test scenarios.