The IMO sub-committee on navigation, communications, search and rescue (NCSR 13)

Information for: Design offices, shipyards, suppliers, manufacturers, owners/managers, and flag states.

Global Maritime Distress and Safety System (GMDSS)

Digital navigational data system (NAVDAT)

NCSR 13 updated a road map for the implementation of NAVDAT, a framework for the digital broadcasting of navigational warnings, meteorological forecasts, safety messages, and search and rescue information on medium-frequency (MF) and high-frequency (HF) bands from shore to ship.

The road map, a living document which may be further updated in the future based on new developments, describes a step-bystep approach, without a fixed timeline. It includes the development, testing and standardization of NAVDAT, with gradual implementation alongside the current terrestrial NAVTEX system for broadcasting maritime safety and search and rescue information.

It is expected that new NAVDAT MF transmitters would support the broadcast of both NAVTEX and NAVDAT messages. NAVDAT HF transmitters, however, can be deployed as a standalone solution for the sole broadcast of NAVDAT messages.

It should be noted that the following relevant NAVDAT performance standards and guidelines have been developed: MSC.569(109), MSC.509(105)/Rev.2, ITU-R M.2010-3, ITU-R M.2058-2 and ITU-R M.2443-0. However, the relevant NAVDAT IEC test standards have not yet been completed.

IMO positions on the 2027 World Radio Conference

NCSR 13 agreed on draft IMO positions regarding the relevant WRC-27 agenda items relating to maritime services. The draft IMO positions seek to ensure that regulatory amendments do not impose constraints on GMDSS and other maritime safety services, and that safety-critical communications are preserved.

The draft IMO positions will be submitted to MSC 112 (December 2026) for approval, for forwarding to ITU, and later for finalization by NCSR 14 and MSC 113 (June 2027).

Guidelines for EPIRB using two-way communication via SAR/Galileo Return Link

NCSR 13 agreed on draft amendments to “Performance Standards for float-free Emergency Position-Indicating Radio Beacons (EPIRBs) operating on 406 MHz” (Resolution MSC.471(101)). The draft amendments introduce the two-way communication service offered by the Galileo Return Link as an optional functionality.

The ICAO/IMO Joint Working Group was instructed to develop guidelines for the operational use of EPIRBs that implement the two-way communication service and to advise NCSR 13, as appropriate.

The draft amendments will be submitted to MSC 112 (December 2026) for approval.

Guidance for global ECDIS S-100 data connectivity

NCSR 13 progressed the development of a regulatory framework to support the safe implementation of nextgeneration Electronic Chart Display and Information Systems (ECDISs). ECDIS S-100 is intended to support safe navigation by providing the real-time display of electronic charts combined with regularly updated digital information from maritime information services.

NCSR 13 finalized draft MSC circulars on:

• Guidance to establish a framework for data distribution and global IP-based connectivity for shore-based facilities and ships supporting ECDIS S-100 products
• Operational guidance for digital route exchange

The development of the guidance follows the adoption of a revised version of the ECDIS Performance Standards (Resolution MSC.530(106)) in 2022, which enables the next technical generation of electronic navigational charts.

The revised performance standards will apply to ECDIS equipment installed on or after 1 January 2029. During the transitional period from 1 January 2026 to 1 January 2029, ECDIS equipment may comply with either the current standards (Resolution MSC.232(82)) or the new performance standards.

The new draft MSC circulars will be submitted to MSC 112 (December 2026) for approval.

Performance standards for augmentation systems (DFMC SBAS) in radionavigation receivers

In May 2026, MSC 111 adopted amendments to Resolution A.1046(27) on the Worldwide Radionavigation System, establishing procedures and requirements for augmentation systems. These systems enhance the performance of Global Navigation Satellite Systems (GNSSs) by improving precision, reliability and availability.

Building on this framework, NCSR 13 initiated the development of performance standards for dual-frequency multi-constellation satellite-based augmentation systems (DFMC SBAS) and advanced receiver autonomous integrity monitoring (ARAIM) in shipborne radionavigation receivers.

The work will continue in a Correspondence Group until NCSR 14 (April 2027).

Performance standards for Ranging mode (R-mode) in radionavigation receivers

NCSR 13 finalized draft performance standards for shipborne Rmode receiver equipment. The performance standards set the minimum requirements for shipboard receivers that provide positioning independent of the Global Navigation Satellite System (GNSS), i.e. a backup system intended to ensure that ships can still navigate safely using terrestrial signals if satellite systems are disrupted.

The draft performance standards will be submitted to MSC 112 (December 2026) for approval.

Transition scheme for digital VHF voice communications

NCSR 13 agreed on a scheme for a stepwise shift from analogue to digital VHF voice communications. The transition scheme includes a gradual introduction of digital channels, where the existing analogue channels 06, 13, 16, 75 and 76, as well as the existing assignments of channels 70 (DSC), AIS 1 (AIS-SART) and AIS 2 (AIS-SART), will be maintained for safety and to prevent disruption of the GMDSS distress, urgency and safety communications.

The indicative timeline can be summarized as follows:

• 2025–2028: development of the transition scheme
• 2028–2031: development of the regulatory framework and standards
• 2032–2045: gradual implementation and replacement of equipment

The transition scheme will be submitted to MSC 112 (December 2026) for approval.

Long-Range Identification and Tracking (LRIT) of ships

NCSR 13 noted that MSC 111 (May 2026) approved, in principle, draft amendments to SOLAS Regulation V/19-1 to introduce the free-of-charge policy for the provision of LRIT information to entitled coastal states. A draft revision of the “Performance standards and functional requirements for the long-range identification and tracking of ships” (Resolution MSC.263(84)/Rev.1) was approved accordingly.

Recommendations

As NCSR 13 is a Sub-Committee, all decisions concerning rules, regulations and dates are subject to further consideration and approval by the Maritime Safety Committee (MSC). DNV recommends that our customers monitor the outcome of MSC 112 in December 2026.

DNV class customers are further encouraged to visit the Compliance Planner to monitor how upcoming statutory requirements will impact their ships.