Results of measurement campaign for characterisation of AIS transmitters

The Automatic Identification System (AIS) is a maritime surveillance system using the VHF band to exchange information between ships and shore stations, including positions, identification, course and speed. It mainly aims at avoiding collisions between ships. The link budgets allow receiving transmitted AIS signals from space, and consequently a global maritime surveillance from space can be considered. However, some challenges arise, especially message collisions due to the use of a SO-TDMA protocol (not designed for satellite detection). Advanced signal processing for separation of received signals is needed. In this paper, we describe a measurement campaign of AIS signals (from many different transmitters) in the Ouessant rail realised to understand the needs of space-based AIS system. Detailed results at different layers are given.