Vessel Tracking Methods
There are many ways a vessel can be tracked, we continue to experiment with a variety of them with the results shown below. A short summary of each type is below
AIS Services
Originally developed as an accident prevention system, this is a VHF based mechanism where vessels receive and optionally transmit information about themselves, such as dimensions, speed, course etc. This information is then typically displayed via ships navigation systems with the intention to avoid collisions while underway. Some vessels (usually large commercial ships) will then send all of the received data via satellite connection to information aggregation services. These same services also deploy land-based VHF receivers that relay received AIS information typically over the internet to their aggregation service.
One of the issues with AIS is that the land-based receivers are usually run by a specific provider and they don't tend to share this information, so vessel tracking for a single provider is only as good as the area covered by their land-based receivers.
Satellite Services
These mostly leverage the Iridium satellite network although some also use the competing Globalstar network. Some solutions such as the YB3i and SPOT are dedicated tracker only solutions, usually with an integrated SOS notification mechanism. There are also tracking solutions built into the more full function satellite options such as the Iridium GO! which also provide things like SMS text, email, and social media updates. All of these are vary bandwidth limited solutions.
Other solutions
These are typically application only solutions that try to consolidate input from various methods into a single visual representation. They typically leverage the information available from the solutions listed above as well as manual update methods such as email or a smartphone app.