Space-based detection of AIS signals: Results of a feasibility study into an operational space-based AIS system

Abstract

An important system in the field of global maritime surveillance is the Automatic Identification System (AIS), which is responsible for communicating ship- and voyage-related data of surface vessels. In order to improve the performance of the existing land-based AIS system, a consortium led by OHB has been responsible for the development of a full-fledged European space-based AIS system. The main challenge in space-based AIS is the collision of multiple AIS messages in a single slot. Several innovative technologies have been applied to the payload to maximize its detection performance. The constellation has been optimized for high performance, sufficient coverage and low timeliness, resulting in 4 orbital planes consisting of 3 satellites each. Orbital parameters are 550 km altitude at 88° inclination. Assessment of the AIS constellation performance is done by using a dedicated AIS simulator applying either present-day or future traffic models. After definition of the use cases, including so-called of High Traffic Zones, which contain exceptionally dense traffic, the performance per use case has been evaluated. Considering all vessels, the user requirements of 1 hour update interval with 80% detection probability for non-HTZ and 3 hour update interval with 80% detection probability for HTZ, can be met for most use cases. For critical use cases, such as North Atlantic or Mediterranean, these requirements will be met for open sea traffic. Such a situation is representative of space-based AIS complementing the already existing infrastructure of coastal stations.