Automatic Identification System (AIS) presents an oppurtunity to exchange and display data between participating vessels to vessels and vessels to shore components.

• Enhance safety at sea
• Giving VTS operators improved control
• Surveillance of vessel traffic

One of the important feature of AIS is the Ship to Ship and Ship to Shore (4s). This features allow the transponder to work without any assistance from the shore or base station. The transponder communicates autonomously, automatically and is totally self organizing.

Main components in the Transponder includes:

• GPS receiver - provide accurate position and navigation data of a vessel
• VHF transceiver - able to receive message, unpack it and plot the position, speed, heading and course of the ship onto an Electronic Chart System (ECS) or ECDIS
• A computational system packs this information together with the vessels speed, name, position, call sign, length and beam, ETA, heading and course to broadcast the data on a digital link via the VHF tranceiver.