Maritime tracking
How Ship Tracking Works
Most public ship-tracking experiences are built around AIS, the Automatic Identification System. AIS-equipped vessels can broadcast identity, position, course, speed, and other information over VHF radio for nearby ships and shore stations to receive.
By TransitSatellite · Reviewed October 20, 2026
The vessel determines its position
The U.S. Coast Guard explains that AIS position and timing information is normally derived from an integral or external global navigation satellite system receiver such as GPS.
That means GPS helps the vessel determine where it is, while AIS provides the broadcast mechanism used to share maritime information with suitable receivers.
AIS broadcasts over VHF
AIS operates in the VHF maritime band and acts much like a shipboard transponder. Depending on vessel movement and equipment, reports can update frequently.
The broadcast can include identity, position, course, speed, navigational status, call sign, MMSI, and other safety-related fields.
Public trackers still need a data network
A public website needs access to a receiving network or licensed data provider before AIS broadcasts become map markers. Coastal receiver coverage and provider policies affect what users can see.
Satellite AIS can extend coverage beyond coastal VHF receiver networks, but commercial satellite AIS data is a separate service and may carry licensing or subscription costs.
Common questions
Does GPS directly track a ship?
No. GPS provides navigation signals that allow the vessel to calculate position. AIS or another communication system is then used to share that position.
Why can a ship disappear from a public tracker?
Receiver coverage, vessel equipment, broadcast intervals, provider filtering, data licensing, and offshore distance can all affect public availability.
Sources
Port Canaveral guide
Connect ship tracking to official cruise and port schedules.
Open guideExternal live ship map
Open a third-party live vessel tracking service.
Open map