🔍 Key Concepts

• LRIT (Long Range Identification and Tracking) purpose and what it is used for under SOLAS • Difference between positioning systems (like GPS) and communication/messaging systems (like Inmarsat and Iridium) • Which satellite services are approved by IMO/flag States to transmit LRIT data

💭 Think About

• Ask yourself: Which of these systems is mainly a navigation/position-finding system rather than a communication/transmission service? • Consider: LRIT needs a way to send your ship’s identity and position to shore. Which options are primarily for sending data messages, and which is not? • Think about which systems are commonly listed with GMDSS equipment and LRIT discussions in SOLAS and flag‑state circulars.

✅ Before You Answer

• Identify which options are two-way satellite communication services used on ships (especially for GMDSS or messaging). • Identify which option is primarily a position-fixing/navigation system, not a communications link. • Recall or verify which systems are named in SOLAS V/19-1 (LRIT requirements) implementation guidance as approved LRIT communication systems.