IEC 61097-4:2024

Overview

IEC 61097-4:2024 is the fourth edition international standard specifying operational and performance requirements, methods of testing and required test results for Inmarsat-C ship earth stations (SES) and Inmarsat Enhanced Group Call (EGC) receivers used within the Global Maritime Distress and Safety System (GMDSS) and for Long-Range Identification and Tracking (LRIT). The standard defines equipment classes, identifies IMO-essential technical characteristics, and references Inmarsat test procedures and installation guidance.

Key topics and technical requirements

• Equipment scope and classes: Defines available variants
  • Class 0: EGC receiver (stand-alone or part of GMDSS installation per Inmarsat DIGs)
  • Class 1: Basic SES for shore-to-ship and ship-to-shore messaging
  • Class 2: Class 1 plus shared EGC receiver (IMO considers class 2 adequate for maritime safety information)
  • Class 3: Class 1 with independent EGC receiver
• Operational capabilities: Distress alerting, ship station identity, position updating, direct-printing communications and EGC reception/indication/printing.
• LRIT functions: Capabilities and functionality required when SES is used for LRIT reporting.
• Performance and environmental requirements: Includes electromagnetic compatibility (EMC), environmental limits, radiated unwanted emissions (Annex B), and operation in presence of interfering signals (new requirement added in clause 5.5).
• Testing and compliance: Detailed methods of testing and required results for operational and technical characteristics (Clause 6). Inmarsat RTP test schedules and where to find Inmarsat procedures are referenced in Annex C.
• Installation and construction: Equipment construction and test requirements are covered; installation matters are covered by the Inmarsat Maritime design and installation guidelines (DIGs) and IMO resolutions reproduced in Annex A.
• Type approval: Responsibility for type approval of Inmarsat‑C/EGC is vested in Inmarsat as per IMO resolutions (see Clause 4.2.1).

Practical applications - who uses this standard

• Equipment manufacturers designing and testing Inmarsat-C SES and EGC receivers for GMDSS and LRIT compliance.
• Test laboratories and certification bodies performing type approval, conformance testing and issuing compliance reports.
• Shipbuilders and marine integrators specifying compliant comms equipment for newbuilds and retrofits.
• Flag states, port authorities and maritime safety administrators evaluating equipment for SOLAS/GMDSS requirements.
• System installers and maintenance teams following installation guidance (Inmarsat DIGs) and verifying operational performance.

Related standards and references

• IMO SOLAS Convention and Resolutions: MSC.513(105), MSC.263(84), MSC.306(87)
• IEC 60945 - general maritime navigation and radiocommunication equipment requirements (as modified)
• Inmarsat technical characteristics, RTP schedule of tests and Design & Installation Guidelines (DIGs)

Keywords: IEC 61097-4:2024, GMDSS, Inmarsat‑C, EGC receiver, ship earth station, LRIT, performance requirements, testing, IEC 60945, IMO, maritime safety, type approval.