Dual-use Cosmo/Skymed data for the monitoring of coastal areas: Azimuth ambiguity filtering

Cosmo/Skymed is a constellation of X-band high-resolution spaceborne Synthetic Aperture Radar (SAR) sensors launched and operated by the Italian Space Agency. It was designed, and is currently employed, as a dual-use system. Within this framework, coastal monitoring and ship detection by using SAR data is of fundamental importance for both military and civilian uses. However, SAR data, and in particular Cosmo/Skymed data, of coastal areas are often affected by azimuth ambiguity effects, which cause the appearance on the image of “ghosts” of brilliant targets that can be erroneously interpreted as real targets (ships, in the ship-detection case). Therefore, for coastal areas monitoring and ship detection, use of azimuth ambiguity reduction techniques is mandatory. In the following, we consider an azimuth ambiguity filtering method that we recently developed and we apply it as a preliminary step for coastal area monitoring. Some criteria to judge the effectiveness of the method are devised and employed to Cosmo/Skymed data relative to the Gulf of Naples (Italy) and Malta coastal areas.