The ascension island experiment: Measurement of ionospheric scintillation effects on PALSAR-2

The effect of the ionosphere on SAR imaging has been studied previously from both an analytic and a numerical simulation perspective. Recently, effects visible in SAR imagery have been ascribed to turbulence in the ionosphere. This paper describes an experiment that seeks to use ground-based GPS measurements of the ionospheric scintillation, collected simultaneously with PALSAR-2 imagery, to unambiguously confirm the predictions of the analytic theory. PALSAR-2 (on board the ALOS-2 satellite) was used in spotlight mode to image a 5m corner reflector to obtain an accurate measurement of the point spread function (PSF). Initial results, obtained during the 2014/15 scintillation season, confirm that the analytic theory describing the shape of the SAR PSF is correct. This is then used to obtain two measures of the scintillation, p and C_kL, directly from the PALSAR-2 PSF. The collected data set can also be used for further research into ionospheric autofocus techniques.