Hybrid SAR/ISAR imaging with VHR spaceborne data for inland waterways surveillance

This work considers the exploitation of very high resolution (VHR) spaceborne SAR data to monitor inland waterways. As moving ships appear defocused and shifted in the SAR images, hybrid SAR/ISAR approaches are needed to make effective the exploitation of the increasing availability of satellite images with high spatial resolutions for enhanced inland waterways awareness. To this purpose, this work puts forward a processing chain that takes in input detected ships from level-1 SAR images and provides in output refocused and scaled images of the ships along with their kinematic information including their correct position on the waterway. Notably, the developed approach assumes single-channel instruments, which represent most of the current spaceborne SARs. The effectiveness of the approach has been tested using VHR Capella SAR images with a resolution of about 46 cm × 44 cm in two different areas, including the Hudson River in the proximity of New York (USA) and the Nieuwe Waterweg canal crossing the port of Rotterdam (Netherlands).