Internet of Things at Sea: Using AIS and VHF over Satellite in Remote Areas

This paper describes how the Automatic Identification System - Application Specific Message (AIS/ASM) via Low Earth Orbit (LEO) satellites can be used to transmit small data between ship and shore to facilitate information visibility in future maritime transport systems. The focus is on ships without advanced satellite terminals in remote areas where terrestrial infrastructure is not available. Here, AIS is proposed as a low cost and general alternative to ordinary satellite communications. In this paper, we report on how reliable ASM is for data exchange, for instance for cargo-monitoring data. One problem is to determine when the LEO satellite is in a geographic position to receive messages from the ship. Another problem is that the AIS satellite can fail to register data, even when in the radio range of the ship, because the ship antenna is constructed for horizontal radiation and sends very little signal upwards, especially when the satellite is at its closest to the ship. The study uses AIS data from the Norwegian Coastal Administration to determine the probability that specific AIS transmitters are detected by the satellites.