Abstract
The monitoring of ships which do not report their Automatic Identification System (AIS) information is important for Maritime Domain Awareness (MDA). In this paper, an improved maritime picture is generated by presenting a new methodology to map these so-called 'dark' ships over time. Firstly, a robust and accurate data association between Synthetic Aperture Radar (SAR) ship detections and AIS data is carried out on multi-temporal SAR imagery and AIS data. Subsequently, Kernel Density Estimation (KDE) is applied to unassigned SAR ship detections to reveal the spatial distribution of `dark' zones (i.e. areas where repeated unassignments occur). This analysis helps identify areas where ships frequently do not report, which can help guide authorities in the best way to respond. The methodology is validated using Sentinel-1 Interferometric Wide (IW) swath mode products and AIS data acquired from the English Channel, UK.