The Automatic Identification System (AIS) is a short-range coastal tracking system currently used on ships. It was developed to provide identification and positioning information to both vessels and shore stations.
Ships of 300 gross tonnage or more sailing on international voyages, cargo ships of 500 gross tonnage or more sailing in local waters, and all passenger ships irrespective of size are mandated by the International Maritime Organization (IMO) to carry AIS equipment. AIS transponders automatically broadcast information at regular intervals. Navigational status data is transmitted every 2 to 180 seconds, depending on a vessel's activity. In addition, voyage related data is broadcast every 6 minutes. These signals are received by AIS transponders installed on other ships or by land-based systems.
The AIS signals have a horizontal range of about 40 nautical miles (74 km), meaning that AIS traffic information is only available around coastal zones or in a ship-to-ship zone. AIS communication takes place using two VHF frequencies, 161.975 MHz and 162.025 MHz, using a bandwidth of 25 kHz. Although only one radio channel is necessary, each station transmits and receives over two radio channels to avoid interference problems, and to allow channels to be shifted among ships without loss of communication.
Space-based AIS (SAT-AIS) will make it possible to track seafaring vessels beyond coastal areas that are equipped with AIS tracking devices. SAT AIS is a promising solution to overcome terrestrial coverage limitations with the potential to provide AIS service for any given area on Earth.
ESA is promoting a European-based SAT-AIS system in partnership with the European Maritime Safety Agency (EMSA). SAT-AIS will greatly increase the coverage and effectiveness of programmes such as SafeSeaNet (SSN) system.
The following groups of users have been identified:
- Maritime security services: support of security operations, vessel traffic/navigation monitoring, vessel traffic management, support of safety operations
- Law-enforcement services: anti-piracy, illegal fishing, enforcement of international/ national regulations, support of enforcement operations
- Search and Rescue (SAR) services
- Maritime surveillance services: monitoring of vessels in sensitive areas, anti-drug smuggling, border control
- Environmental services: hazardous cargos monitoring, prevention of pollution caused by ships, pollution response
- Fleet management services for commercial users (shipping companies and ship owners)
SAT-AIS is being developed through three ARTES programme elements:
ARTES 5 – Specific technology predevelopment activities, including antenna miniaturisation, receiver developments, and a performance testbed in the form of an end-to-end simulator.
ARTES 20 – Implementation and validation of a Data Processing Centre as “space node” in close cooperation with and co-funding from the European Maritime Safety Agency for full data integration into SafeSeaNet services.
ARTES 21 phase 1 – Initial steps of the system design and implementation, including estimating the economic potential by means of a cost-benefit analysis of an Operational Demonstration Mission (ODEM), system design studies, comparative performance assessments, as well the exploration of a possible Public Private Partnership (PPP) implementation scheme for the European SAT-AIS operational system.
ARTES 21 phase 2 – covers the detailed design and implementation of the SAT-AIS microsatellites and payloads, and the development of innovative SAT-AIS applications and services. Following the system definition and trade-off analysis carried out in preliminary studies, a constellation of so-called microsatellites has been retained as the most cost-effective solution for providing SAT-AIS services and maintaining its viability. For this commercially-oriented project, called E-SAIL, LuxSpace will be the industrial prime contractor. In parallel, ESA is also developing a SAT-AIS payload for the forthcoming Norwegian NORSAT -1 mission, which will also fly two additional scientific payloads. Kongsberg Seatex is the prime contractor responsible for defining the technical system requirements, the development, manufacturing, assembly, test and qualification of the Novel SAT-AIS Receiver, NAIS. The operator of the NORSAT-1 satellite will be the Norwegian Space Centre (NSC). NSC will be responsible for the top-level mission requirements.