🔍 Key Concepts

• LRIT (Long Range Identification and Tracking) purpose and who receives the data • Difference between AIS (Automatic Identification System) and LRIT (broadcast vs secure reporting) • Which satellite systems use Inmarsat-C vs Inmarsat-B for data reporting

💭 Think About

• Ask yourself: Is LRIT intended to be a duplicate / backup of AIS, or a separate regulatory system with a different function and data path? • Consider whether LRIT signals are meant to be received by other ships nearby, or by shore-based authorities via satellite. • Think about which Inmarsat service (B or C) is commonly used for low‑bandwidth data and reporting functions like distress alerts and tracking.

✅ Before You Answer

• Verify which system (AIS vs LRIT) operates on VHF radio frequencies and is line-of-sight, and which one uses satellites. • Check which Inmarsat service (Inmarsat-C or Inmarsat-B) is associated with store-and-forward data messaging and regulatory tracking services. • Confirm whether LRIT ‘polls’ other stations, or whether ships report their own position automatically at set intervals via satellite.