The 13th session of the IMO Sub-Committee on Navigation, Communications and Search and Rescue (NCSR 13) met from 22 to 26 June 2026. Its report to the Maritime Safety Committee (NCSR 13/18, with annexes in NCSR 13/18/Add.1) records several outcomes that touch VDES directly.
- A performance standard for shipborne R-mode
NCSR 13 agreed a draft MSC resolution on performance standards for shipborne R-mode receiver equipment (Annex 11), forwarded to MSC 112 with a view to adoption. The standard is explicit that VDES is one of R-mode’s two carriers: VHF R-mode signals are transmitted as part of VDES on its specific channels, alongside medium-frequency broadcasts in the 283.5 to 325 kHz band. It covers the basic functional requirements of position fixing, determination of course over ground, speed over ground, and timing. The Sub-Committee agreed that R-mode should serve as a backup supplementary to GNSS, and that amending the Worldwide Radionavigation System resolution (A.1046(27)) to formally incorporate R-mode would be premature at this stage.
- WRC-27: protecting maritime spectrum
NCSR 13 finalised the draft IMO position on ITU WRC-27 agenda items concerning maritime services (Annex 6), for approval by MSC 112 and submission into the ITU process, with the final position to be prepared by NCSR 14. The work is directed at protecting GMDSS and maritime radio services in the coming spectrum negotiations, and includes new allocations to support the implementation of R-mode in the VHF maritime mobile band.
- An S-100 connectivity framework
NCSR 13 agreed a draft MSC circular 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 (Annex 8), also going to MSC 112. IALA recommended that the framework use the Secure Communication between ship and shore (SECOM) infrastructure and the Maritime Connectivity Platform (MCP) as the reference solution for secure communication, identity, trust and service discovery. The Maritime Messaging Service (MMS) is referred to as an optional technology in the guidance. The circular does not designate VDES as an S-100 transport and imposes no carriage requirement on ships.
- LRIT under discussion
NCSR 13 recorded a discussion of Long-Range Identification and Tracking (LRIT). Several delegations pointed to the declining use of LRIT for search and rescue and to the availability of competing technologies. Separately, MSC 111 has approved a move to a free-of-charge policy for the provision of LRIT information to entitled coastal States. This is relevant to VDES because, with authentication, VDES can provide the same function and considerably more.
- GMDSS resilience
Several administrations raised concerns at NCSR 13 about the practical accessibility of satellite GMDSS services, including service limitations imposed for non-technical reasons. IMSO reported that even on affected terminals, GMDSS services remained available in line with the applicable resolution. VDES, as a potential future GMDSS technology, is an open standard, allowing multiple countries to implement complementary, compatible solutions with sufficient redundancy to mitigate the potential impact of commercial or political conflicts on safety of navigation services.
- Position quality: DFMC SBAS and ARAIM
NCSR 13 advanced work on performance standards for dual-frequency multi-constellation satellite-based augmentation systems (DFMC SBAS) and advanced receiver autonomous integrity monitoring (ARAIM) in shipborne radionavigation receivers, re-establishing a correspondence group to finalise the standards for NCSR 14. This work improves position quality, including in regions where GNSS interference degrades AIS and VDES position reporting.
In summary
VDES remains complementary to the work of IALA, ITU, IMO, IEC and RTCM rather than a replacement for any of it. NCSR 13 is a useful marker of how far the groundwork has come, and Alliance members are building the equipment that turns these standards into working systems at sea. The full report is available as NCSR 13/18 and its addendum NCSR 13/18/Add.1 at https://docs.imo.org.
VDES Alliance Contributing Members can access the referenced annexes through the VDES Alliance Contributing Members SharePoint.