AIS Technology
Terrestrial AIS Data
Get near real-time vessel positions with updates every 2-10 seconds. Terrestrial AIS provides the highest frequency tracking for vessels in coastal waters and port approaches.
What is Terrestrial AIS?
Terrestrial AIS (T-AIS) uses a network of shore-based receiving stations positioned along coastlines worldwide to capture AIS transmissions from nearby vessels. These ground stations provide extremely high-frequency position updates for ships within range.
With a typical range of approximately 50km (depending on antenna height and atmospheric conditions), terrestrial AIS delivers position updates every 2-10 seconds — significantly faster than satellite AIS. This makes it essential for time-critical applications like port operations and vessel traffic services.
Shore-based stations offer direct line-of-sight reception, providing cleaner and more reliable signals than satellite AIS with minimal latency between vessel transmission and data availability.
How Terrestrial AIS Works
A global network of shore-based stations provides high-frequency vessel tracking in coastal waters.
Vessel Transmits
Ships continuously broadcast AIS signals on VHF frequencies. Faster vessels transmit more frequently (every 2 seconds at high speed, every 10 seconds when anchored).
Station Receives
Coastal receiving stations with elevated antennas detect these VHF signals. Multiple overlapping stations ensure coverage of major ports and shipping lanes.
Instant Delivery
Data is immediately processed and made available through our API with sub-second latency. Perfect for real-time operational applications.
Technical Specifications
Terrestrial vs Satellite AIS
Understanding when to use terrestrial versus satellite AIS data.
| Aspect | Terrestrial AIS | Satellite AIS |
|---|---|---|
| Update Frequency | Every 2-10 seconds | Every few minutes |
| Coverage | Coastal waters (~50km from shore) | Global oceans, including open sea |
| Best For | Port operations, coastal monitoring | Ocean crossings, global tracking |
| Key Advantage | Highest update frequency | No geographic limitations |
Coverage Areas
Terrestrial AIS provides comprehensive coverage of key maritime regions.
Major Ports
Complete coverage of the world's largest commercial ports and harbors.
Shipping Lanes
Dense coverage of major coastal shipping routes and traffic separation schemes.
Straits & Chokepoints
Singapore Strait, English Channel, Strait of Gibraltar, and other critical waterways.
Anchorages
Monitor vessels waiting at anchor outside ports for berth availability.
Territorial Waters
Coverage of national territorial waters for security and customs monitoring.
Pilot Boarding Areas
Track vessels approaching pilot stations and boarding positions.
Terrestrial AIS Use Cases
Applications that require high-frequency position updates.
Port Operations
Manage berth assignments, pilot scheduling, and vessel traffic with near real-time position data. Track arrivals, departures, and vessels at anchor.
Vessel Traffic Services
Support maritime traffic management with high-frequency updates. Monitor vessel movements, detect potential conflicts, and ensure safe navigation.
Terminal Operations
Coordinate container and bulk terminal operations with precise vessel tracking. Optimize crane scheduling and cargo handling based on vessel positions.
Tug and Pilot Services
Track pilot boat and tug positions alongside assisted vessels. Coordinate pilot boarding, tug assignments, and escort operations.
Coastal Surveillance
Monitor coastal waters for security, customs, and fisheries enforcement. Track vessels entering territorial waters and port approaches.
Supply Chain Visibility
Provide accurate ETAs for vessels approaching port. Update supply chain systems with real-time arrival information for logistics planning.
Frequently Asked Questions
How often does terrestrial AIS update vessel positions?
Terrestrial AIS provides position updates every 2-10 seconds for vessels in range. The exact frequency depends on the vessel type and speed — faster moving vessels transmit more frequently. This is significantly faster than satellite AIS which updates every few minutes.
What is the coverage range of terrestrial AIS?
Terrestrial AIS receivers typically cover vessels within approximately 50km of the shore-based station. Coverage depends on antenna height, atmospheric conditions, and local geography. Most major ports and coastal shipping lanes have overlapping coverage from multiple stations.
What happens when a vessel leaves terrestrial range?
When a vessel moves beyond terrestrial AIS range (~50km from shore), our API automatically switches to satellite AIS data. You get seamless coverage — high-frequency updates near shore, then satellite tracking as the vessel goes to sea.
Is terrestrial AIS data included in all plans?
Yes, all Data Docked plans include combined terrestrial and satellite AIS data. Our pricing page shows terrestrial-only options which are lower cost if you only need coastal coverage.
Start Tracking in Real-Time
Access high-frequency terrestrial AIS data through our simple API. Get near real-time coastal coverage with a free trial.