Using GNSS-R Imaging of the Ocean Surface for Oil Slick Detection

Even though reflectometry using Global Navigation Satellite System´s signals (GNSS-R) was first envisioned for mesoscale ocean altimetry, nowadays a number of different applications have been developed (ocean scatterometry, ice monitoring, soil moisture retrieval, etc.). Recently, imaging of the ocean surface from a GNSS-R spaceborne receiver has been proposed by treating the measured delay-Doppler Maps (DDM) as a blurred image of the surface´s scattering coefficient in the delay-Doppler domain. Thus, by deconvolving the DDM with the GNSS code Woodward ambiguity function (WAF), and appropriate domain transform, an image of the surface´s scattering coefficient distribution can be obtained. In this work this technique is applied to oil slick detection. A realistic scenario is simulated, and the performance of the GNSS-R imaging technique is evaluated on the retrieved image. Error below 10% in the retrieved scattering coefficient distribution is achieved (except for regions affected by deconvolution artifacts), and the image resolution of the order of 2 km is comparable to that of a synthetic aperture radar (SAR) system with equivalent specifications.