200532 AIS Initialisation

AIS Initialisation
MARS Report 200532

It is very important to ensure that a ship's AIS has been set-up with the correct static data when the equipment is commissioned. Also, since this data can be corrupted, perhaps by inquisitive tampering by an unskilled user, it is important that the stored static data is verified from time-to-time by a knowledgeable bridge officer.

A particular problem, which can have alarming consequences, occurs when the MMSI number has not been correctly entered. The AIS broadcast system relies on each station having a unique MMSI. It is this number which is used by the system to discriminate transmissions from any particular station. If more than one ship station is broadcasting the same MMSI number, inconsistencies (such as 'target-swap') occur when ship information from these stations is displayed on receiving systems.

This installation problem has been particularly noted for vessels that are erroneously broadcasting 1193046 as the default MMSI. This number is the default MMSI used on at least one version of AIS equipment manufactured by Nauticast. If users of this equipment have not properly entered the vessel's MMSI as described in the installation procedure, this number is broadcast. Two or more ships simultaneously using this MMSI have been reported. Users of all AIS systems should check the validity of the static data stored within the equipment after installation and regularly thereafter.

Although this report specifically mentions Nauticast, it is not intended to suggest that there is anything wrong with the Nauiticast product and it may well apply to any other make of AIS equipment. The ship operators must check that the correct data for their vessel has been installed in the equipment.

Nauticast have been made aware of this but are very keen to stress that they take every possible precaution to ensure that the installers and operators programme their equipment properly. This includes supplying a Windows Software tool for training, running Training Courses and providing explicit documentation. All the documentation prominently specifies that the first action after installation of the hardware is to input the ship's correct MMSI number. Nauticast also provide technical support and a dedicated web interface for their agents. They also say that, if their default MMSI is being broadcast, in contrast to other manufacturer's equipment, everyone is able to recognise this and contact the vessels to inform them that they should correct their data. R.B