1. What is AIS?

Inland AIS is based on the Maritime AIS. AIS uses radio technology. Through radio signals AIS stations, sometimes called AIS transponders, send out messages.

These messages can be received by all other AIS stations, on ships and onshore, in the vicinity of the sending station within VHF radio range. This happens automatically and periodically, with shorter or longer intervals. A fast-moving ship will send out AIS messages at shorter intervals than a ship that is travelling slower or is moored. Two special VHF radio channels are reserved to exchange AIS messages.

Certain hardware and software is needed for AIS. The hardware is an AIS station with built-in GPS. For a user-friendly presentation of the content of AIS messages, additional equipment (e.g. Inland ECDIS, see chapter 3) is needed.

The information in these messages includes the identity of the ship, the position, and other ship-related information (see chapter 2 for details). Some of the information, such as ship identity and position, is automatically broadcast. Other information, such as navigation status, destination, and dangerous cargo category (blue cones), can be input manually by the skipper. All data that is input manually has to be accurate and valid.

Schema

Warning

The following points should be considered when using information conveyed by AIS :

• Always bear in mind that other ships may not be equipped with AIS; an AIS station installed on another ship might transmit incomplete, erroneous or not updated information; AIS may fail; or AIS might be switched off.
• Not all shore infrastructures are equipped with AIS base stations, e.g. locks and Vessel Traffic Service (VTS) centres.
• Users should ensure that they are able to correctly interpret the data received.
• AIS is purely an additional source of information. It does not replace navigational aids such as radar, but is intended to support them.