- The Westerschelde is a busy shipping lane with continuous activity of a variety of vessels.
- There are several land-based AIS receivers, providing good coverage.
- I am familiar with the waterway, harbours and some of the ships.
The backends run on a headless Raspberry Pi 4, that consumes less than 5 Watts of power.
Why conceive a homemade AIS viewer?
As ever so often, the project spiraled out of hand, starting off from a sailing skipper's interest in the technical principles and data structures of AIS, including the peculiar 6 bit encoding.
Once a working solution, depending on proprietary services, was at hand, the idea of a second implementation with open source tools was born.
All very basic.
All just for fun.
What is AIS?
The automatic identification system (AIS) is an information and tracking system that uses VHF transceivers on ships, to disseminate information to surrounding vessels, and conversely, to receive information from them.
Ships broadcast static data (e.g. their unique Maritmime Mobile Service Identity, vessel name, and voyage related data) as well as dynamic data (e.g. position, course, and speed).
Depending on vessel category, navigational status, and speed, any given ship may emit AIS messages at intervals of 2 - 30 seconds.
AIS complements radar for situational awareness and collision avoidance. AIS signals may be received by ships, maritime vessel traffic services, commercial or private land-based stations, as well as by satellites.
A number of companies supply global AIS data to subscription customers, who may be fleet owners, logistic providers, freight proprietors, financial services and insurance companies, amongst others. Often, a limited functionality is made available to the public via dedicated websites.