Overview
ISO 22090-3:2014 - Ships and marine technology - Transmitting heading devices (THDs) - Part 3: GNSS principles specifies the requirements for transmitting heading devices that determine and provide a ship’s true heading using GNSS principles (measuring RF carrier phase of GNSS signals). The standard sets out general requirements for construction, performance, testing and interfaces as required by Chapter V of SOLAS 1974. It is intended for THDs that feed heading information into bridge systems and integrated navigation systems.
Key topics and requirements
- Scope and principle: THDs based on GNSS principles - heading derived from GNSS carrier-phase measurements of directional sources (GNSS antennas).
- Performance & functionality: Devices must output true heading, allow alignment to the ship’s fore-and-aft line, protect manual correction parameters, and support continuous operation under environmental stresses.
- Operational envelope: Minimum operating range from 70° S to 70° N latitude and capable of handling a maximum rate of turn of 20°/s.
- Availability & resilience:
- Settling time: less than 10 minutes in static conditions with a usable satellite almanac.
- Compensation for brief GNSS signal interruption: maintain heading accuracy for 60 s during signal loss.
- Alerting: required alerts for device malfunction/power failure and GNSS interruption exceeding 60 s; alert interfaces must follow Bridge Alert Management (IMO Res. MSC.302(87)).
- Accuracy and errors: Defines and requires testing for static error (settle point error), dynamic error, and follow-up error; specifics are addressed through type tests and accuracy tests in the standard.
- Type tests and conformity: Includes settling-time tests, static/dynamic/follow-up error tests, back-up, environmental (vibration, humidity, temperature), EMC, interface and malfunction tests (see clauses 6.x).
- Interfaces & presentation: Compatibility with maritime digital interfaces (e.g., IEC 61162 series) and presentation requirements per IMO/IEC guidance; displays and outputs shall indicate true heading.
Applications and who uses it
- Shipbuilders, OEMs and manufacturers of GNSS-based heading sensors and THDs
- Bridge system integrators and suppliers of Integrated Navigation Systems (INS)
- Naval architects, marine electronics engineers, classification societies and flag administrations for type approval and compliance checks
- Ship operators and operators of high-speed craft requiring certified heading information for navigation and safety systems
- Test laboratories performing type approvals and EMC/environmental testing
Related standards
Keywords: ISO 22090-3:2014, transmitting heading devices, THD, GNSS principles, SOLAS, marine navigation, heading accuracy, settling time, GNSS interruption, bridge alert management.