AIS → Annual testing of Automatic Identification System (AIS)

SOLAS Chapter V, Regulation 18.9 states:

“The automatic identification system (AIS) shall be subjected to an annual test. The test shall be conducted by an approved surveyor or an approved testing or servicing facility. The test shall verify the correct programming of the ship static information, correct data exchange with connected sensors as well as verifying the radio performance by radio frequency measurement and on-air test using, e.g. a Vessel Traffic Service (VTS). A copy of the test report shall be retained on board the ship.”

The Maritime Safety Committee, at its eighty-third session (3-12 October 2007), approved the Guidelines on annual testing of the Automatic Identification System (AIS) developed by the Sub-Committee on Flag State Implementation.

AIS annual test

The purpose of an annual testing is to determine that AIS is operational as defined in appropriate performance standards - the International Maritime Organization (IMO) Performance Standard (MSC 74(69)) and IEC standard, IEC 61993-2: Maritime Navigation and Radio Communications Equipment and Standards – Automatic Identification Systems (AIS).

The annual testing of the automatic identification system (AIS) should be carried out by a qualified radio inspector authorized by the administration or a recognized organization under the following testing procedure.

The radio inspector shall have the major and auxiliary equipment required for correctly performing the inspection - the AIS Tester - which helps to decode and check all programming information, as well as to carry out the Performance tests - to measure frequencies, output power, poll information, send to and receive data from AIS.

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AIS → Maritime Survival Locating Systems (“Man overboard devices”)

These ‘MSLS’ or ‘MOB’ devices and systems are intended for very short-range crew retrieval applications. The MSLS is designed to allow for self help from the vessel or organisation where there is a risk of crew falling overboard by sounding an alert from the onboard receiver.

They are not part of the GMDSS, but may use frequencies which can be detected by both GMDSS vessels and non-GMDSS vessels.

One example is a device transmitting on VHF Ch.70 using DSC, having an integral GNSS receiver, and transmits periodically, an automated Distress-priority alert and DSC message with the associated text ‘MAN OVERBOARD’. The DSC message contains the GNSS position and time, which will be displayed on the vessel’s VHF DSC receiver. The units may also be fitted with an alerting light flashing at not-less than 20 flashes/min. If fitted, the light shall be capable of operating at least 6 h, which is also the main battery operation requirement. It may also be capable of being water activated.

A number of devices used as Man Overboard Devices (Maritime Survivor Locating Systems/Devices) use AIS technology based on the burst transmissions defined in Annex 9 of Recommendation ITU-R M.1371. Early versions of these devices have the maritime identity of the format 970xxyyyy, but newer units starting from 2011, use the format 972xxyyyy, (see footnote 1 below the Table), which has been internationally agreed in Recommendation ITU-R M.585-6, Annex 2, Section 2.

The devices should be certified by a competent testing house that they are sufficiently compliant with the IEC 61097-14 for the purpose it is intended, or fully compliant with overseas standards, such as RTCM 11901.1 (June 2012). Additional overseas standards for these devices are under development.


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AIS → Shipborne Automatic Identification System (AIS)

AIS is included in the Safety of Life at Sea (SOLAS) Convention, and large ships began fitting AIS in July 2002. AIS transmits, automatically and at set intervals, dynamic information relating to the ship’s course, speed and heading; static information related to the ship’s name, length, breadth; and voyage-related details such as cargo information and navigational status (e.g. underway or at anchor).

Put simply, the Automatic Identification System (AIS) is a Very High Frequency (VHF) radio broadcasting system that transfers packets of data over the VHF data link (VDL) and enables AIS-equipped vessels and shore-based stations to send and receive identification information that can be displayed on a computer or chart plotter.


Especially when used with appropriate graphical displays, this information can help in situational awareness and provide a means to assist in collision avoidance. AIS transceivers can be found interfaced to radars and ECDIS (Electronic Chart Display and Information System) displays. When interfaced to a radar, AIS can be a source of target information, in addition to conventional ARPA (Automatic Radar Plotting Aid). AIS fitted to real (physical) aids to navigation such as floating buoys and beacons. AIS base stations can broadcast a non-physical “synthetic” AIS AtoN to appear at the location of a real (physical) AtoN on an AIS-enabled display system (e.g. AIS, ECDIS or radar). AIS base stations can also broadcast a non-physical “virtual” AIS AtoN at a particular location when no real (physical) AtoN exists.

Although AIS is not part of the GMDSS, it can be considered part of the GMDSS due to the advent of the AIS-SART (AIS Search and Rescue Transmitter), which can be used in lieu of a search and rescue radar transponder (SART), since 01 January 2010. AIS transceivers on ships also have a simple text communications capability called Short Safety- related Messaging (SSRM), but does not constitute a distress- alerting system, and uses the VHF maritime mobile band.

Each AIS station consists of one VHF transmitter, two VHF receivers (AIS 1 and AIS 2), one VHF DSC receiver (CH.70), a standard marine electronic communications link and sensor systems. Timing and positional information comes from a Global Navigation Satellite System (GNSS) receiver.

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Guidance on AIS devices agreed

The Sub-Committee endorsed a draft Safety of Navigation (SN.1) circular providing information to seafarers on the display of AIS-SART, AIS Man Overboard (MOB) and EPIRB-AIS devices, for submission to the MSC for approval.


GMDSS modernization on agenda

The modernization of the Global Maritime Distress and Safety System (GMDSS), e-navigation implementation and new and amended ships’ routeing proposals are among items on a busy agenda as the third session of IMO’s Sub-Committee on Navigation, Communication, Search and Rescue (NCSR) gets underway (29 February-4 March).