Overview
IEC 61108-1:2003 - "Maritime navigation and radiocommunication equipment and systems - GNSS - Part 1: GPS - Receiver equipment - Performance standards, methods of testing and required test results" - defines minimum performance requirements for shipborne GPS receivers used for navigation. Based on IMO Resolution MSC.112(73) and the GPS Standard Positioning Service (SPS) specification, the standard specifies what GPS receiver equipment must deliver (positioning, speed and course), how it must be tested, and what test results are required for type approval and compliance.
Key topics and technical requirements
- Scope and applicability: Shipborne GPS receivers for navigational use (ships up to 70 knots); covers position fixing, differential corrections, speed and direction determination.
- Operational signals: Receivers shall operate on GPS L1 C/A code (SPS).
- Output format and datum: Position output in WGS‑84 coordinates (latitude/longitude in degrees, minutes and thousandths) and solution time referenced to UTC (USNO). Conversions to other chart datums are permitted but must be clearly indicated.
- Minimum facilities: Antenna, GPS receiver/processor, access to computed position, data control/interface and display or other outputs.
- Interfaces and messaging: Requires compatibility with the IEC 61162 digital interface family (notably outputs for COG, SOG, UTC with validity marking). High‑speed craft require an IEC 61162‑2 interface at 2 Hz.
- Performance & integrity: Includes accuracy requirements aligned with the GPS SPS Performance Standard and integrity-related definitions (e.g., RAIM concepts referenced).
- Testing methods: Clause 5 covers test sites, sequence, standard test signals, accuracy determination, test conditions, acquisition-time limits, interference / immunity tests (broadband and CW masks), and IEC 60945 environmental checks. Test results and pass/fail criteria are specified for type approval.
- Quality assurance: Equipment should be designed, produced and documented under approved quality systems.
Applications and users
IEC 61108-1 is used by:
- Shipborne GPS manufacturers and product designers to meet maritime performance and interface requirements.
- Test laboratories and type-approval authorities validating receiver performance, interference immunity and accuracy.
- Shipyards, system integrators and ECDIS/Pilot‑age system integrators ensuring compliant position feeds.
- Flag administrations, classification societies and procurement teams specifying compliant navigation equipment.
Related standards
- IEC 60945 - general maritime equipment requirements and testing
- IEC 61162 (all parts) - maritime digital interfaces (NMEA/serial and Ethernet)
- IMO Resolutions: MSC.112(73), A.529(13), A.694(17), A.815(19)
- GPS SPS Performance Specification (US DoD)
Keywords: IEC 61108-1:2003, GPS receiver equipment, maritime navigation, GNSS, performance standards, methods of testing, IMO MSC.112(73), WGS-84, IEC 61162, IEC 60945.