AIS – Automatic Identification System

Core AIS theory plus the MaritimeHub AIS network – shore stations, Pi nodes, decoders, maps and tools.
Use this menu to move between fundamentals, our project and hands-on guides.

What Is AIS?
How AIS Works
Message Types & Fields
Class A vs Class B vs AtoN
Frequencies, Range & Propagation
NMEA & Data Formats
Decoding Pipeline
Data Quality
SAT-AIS vs Terrestrial
Privacy, Legal & Ethics

Project Overview & Goals
Network Architecture
Hardware BOM
Software Stack
Station Naming & Leaderboard
Coverage Map & Station Directory
Node Health, Uptime & Alerts

Host a Shore Station
Build-Your-Own Node
Donate Hardware / Sites
Report Coverage Gaps & Issues
Join the Discord / Forum
Contributor Guidelines

Live AIS Map
Port & Anchorage Views
Playback & Rewind
Alerts & Notifications
Vessel Pages
Data Downloads & API
Integrations
Ports, Pilots & VTS Use Cases
Security Considerations
Case Studies & Articles
FAQs

No Targets / Low Range
Decoder Problems
Time & Position Errors
Duplicate / Phantom Targets

Station Install Checklist
Site Survey Form
Maintenance & Inspection Log

Radio Horizon / Range
Feedline Loss & Gain Budget
Update Rate & Slot Utilization
MMSI / Message Field Inspector

AIS · Automatic Identification System

AIS Hub – Signals, Stations & Data

Learn how AIS works from antenna to API, then dive into the MaritimeHub AIS network – Pi nodes,
shore stations, live maps and tools you can build on. Everything organised for both officers
and tinkerers.

Class A & Class B
Shore stations & Pi nodes
Live maps & APIs
Ports, pilots & VTS

📡 For: Bridge teams · Pilots · VTS · RF hobbyists · Devs
🧭 Mode: Learn · Deploy · Integrate

Start here

What are you trying to do with AIS today?

Pick the card that matches your goal – understand the system, help grow the MaritimeHub network
or plug AIS into your own tools.

📖 Learn the basics

New to AIS? Start with what it is, how messages work and why SOLAS ships must carry it.

Go to AIS fundamentals →

🏗 Host or build a station

Use a Pi and SDR to feed MaritimeHub, or host a shore site with better height and coverage.

Open MaritimeHub AIS project →

🧩 Use the data

View live maps, playback tracks, export CSV/JSON or integrate AIS into OpenCPN and apps.

Jump to maps, downloads & APIs →

Browse by system

AIS from antenna to API, mapped out

Follow the path from a ship’s antenna, through VHF and decoders, into the MaritimeHub AIS network
and out to live maps, alerts and integrations.

A) Signals & messages

How AIS uses two VHF channels, time slots and message types to keep targets updating in
busy sea lanes – and what each field actually means on your ECDIS or plotter.

VDL & TDMA
Class A / B / AtoN

View signal path & message fields →

VHF antenna and mast electronics – the starting point for every terrestrial AIS target.

Tools & quick access

Coverage planners, gain budgets and inspectors

Fast links for people installing, tuning or integrating AIS – estimate range, check feedline losses
and inspect raw messages without digging through docs.

📡 Radio horizon & coverage

Simple seabreeze calculator: antenna height vs expected radio horizon and overlap between sites.

Open horizon & range tools →

📶 Feedline loss & gain budget

Coax loss, LNA gain and splitter penalties – keep your station above the noise floor.

Open loss / gain calculator →

🧪 Message inspector & slots

Decode a raw VDM line, inspect MMSI and fields, and see how it fits into the TDMA slot map.

Open MMSI & slot tools →

Latest from AIS

Network snapshot, new nodes and deep dives

As the MaritimeHub AIS network grows, this area can auto-pull new station announcements, RF guides,
incident reconstructions and integration walkthroughs.

Today’s AIS snapshot (demo)

Placeholder metrics – later this can be fed from live node stats, coverage maps and alert logs.

26 active MaritimeHub AIS nodes online · 4 in maintenance / testing

Network · Node health & uptime
New shore station covering western approaches – 45+ NM typical range

Coverage · Range & RF optimisation
Three spoofing / ghost-target events flagged by sanity checks this week

Security · Data quality & filtering

Latest AIS articles
View all AIS articles →

Building a Pi-based AIS shore station from scratch

Projects · Hardware & nodes
Making sense of AIS message types 1, 2, 3, 5, 18 and 24

Theory · Messages & fields
From NMEA 0183 to JSON – decoding pipelines that scale

Engineering · Data formats & APIs

Common problems

Quick guides for the issues that show up most often when setting up or maintaining AIS nodes.

Great circle of silence – station sees almost no targets
Range
VDM lines present but decoder shows heavy message loss
Decoder
Targets jump or smear because time / GPS is drifting
Time & sync
Duplicate or phantom targets clutter the map
De-dup

Contributing & building skills

Grow the MaritimeHub AIS network – and your RF skills

Whether you host a full shore station, run a Pi node from a balcony or help with software,
this area shows how to plug in and what skills you’ll build along the way.

📡 Host a shore station

Have roof space or mast access near the coast? See what we need and what you get in return.

View station requirements →

💻 Dev & data contributors

Help with decoders, dashboards, APIs, visualisations and sanity-check logic.

Open contributor guidelines →

Community picks

Most saved by AIS users this week

Resources most often bookmarked by MaritimeHub AIS contributors and bridge teams in the last 7 days.

Standardised AIS station install checklist

One master list for mounts, grounding, lightning, coax runs and configuration screenshots.

Checklists · Install
Sample kplex / SignalK + API stack for a Pi node

Docker-ready configuration you can adapt for your own node or lab setup.

Stack · Containers
Harbour incident reconstruction using playback & geofences

Walk-through of an anonymised near-miss using time-slider and exported CSV tracks.

Case study · Safety

AIS station photos

Simple coastal AIS mast – VHF antenna, feedline and lightning protection feeding a shore station.