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Frequently Asked Questions

AIS 2.0/VDES (VHF Data Exchange System)

AIS 2.0 is an umbrella term covering AIS (Automatic Identification System), VDES (VHF Data Exchange System), and supplementary technologies such as IHO’s S-100 data format and the Maritime Connectivity Platform (MCP) / Maritime Messaging Service (MMS). 

AIS is a one-way digital exchange of a vessel’s identity, position, and speed. It has been a global standard since 2001 (ITU-R M.1371-1) and a SOLAS requirement since the same year. AIS 2.0 (VDES) takes this further by enabling two-way digital data exchange. It became a global standard in 2022 (ITU-R M.2092-1) and is confirmed to become a SOLAS requirement on 1 January 2028. 
AIS 2.0 is specifically designed to transfer data without using an IP address. This means digital communication can reach the ship’s bridge without exposing it to remote access – no IP address is effectively an unbreakable firewall, making remote log-in simply impossible. By contrast, all currently available satellite communication systems rely on an IP address when transferring data. 

With more than ten years of experience developing and standardizing VDES technology, Sternula is a co-founder of the VDES Alliance and the world’s first commercial VDES satellite operator, following the launch of Sternula-1 on 3 January 2023.

AIS 2.0 is a key enabler of the IMO e-Navigation Strategy Implementation Plan, which requires the digitalization of 15 mandatory services from maritime authorities to ships. AIS 2.0 provides the communication infrastructure to deliver these services efficiently and securely. 
VDE-SAT refers to VDES transmitted via satellite, while VDE-TER is terrestrial VDES, transmitted from ground stations on shore. Both variants support two-way data exchange but differ in coverage and deployment context.
VDE-SAT allows maritime authorities to deliver their mandatory services to vessels across the full Exclusive Economic Zone (EEZ). The satellite provides broad area coverage and can reach beyond the range of terrestrial VDES infrastructure, or serve areas where no such infrastructure exists at all. 
Yes. Ship-to-ship communication is supported in two ways: via direct line-of-sight communication or through a satellite connection. 
AIS 2.0 does not eliminate spoofing, but it significantly reduces the risk. With a data rate 30 times higher than legacy AIS, and through the use of MCP/MMS, it is possible to attach a digital signature to a vessel’s transmitted identity. This ensures the information is verifiably trustworthy. The use of digital signatures is defined in IALA Guideline G1117-1 MCP. 
An AIS/VDES transceiver, designed and tested to IEC 61933-2 and ITU-R M.2092-1 (as applicable). We also recommend installing the Sternula MMS Proxy Ship for full functionality.
No. The new AIS 2.0/VDES transceiver incorporates both AIS/ASM and VDES/AIS 2.0, meaning AIS will continue to operate alongside the newer technology. Much in the same way that 3G and 4G, or 4G and 5G, coexist in mobile networks. 
Latency varies depending on your geographic location. Please contact us for information specific to your area of operations.
VDES frequency usage is defined in the ITU-R M.2092-1 recommendation document (M.2092-2).
Please refer to the ITU-R M.2092-1 document for the full frequency allocation diagram.
 
Yes. Data can be transmitted from ship to shore via either VDE-SAT (satellite) or VDE-TER (terrestrial). 
VDE-SAT provides coverage over an area with approximately a 1,000 km radius per satellite pass.
Revisit frequency depends on your latitude. Please contact us for details relevant to your region. 
No. VDES is designed for text-based data communication only. Voice and video are not supported. 
Yes, in principle. Because VDES operates without an IP address, data can be routed to the ECDIS display. However, actual compatibility depends on the ECDIS provider and the level of integration implemented. 

Further technical information is available in IALA Guideline G1117. 

We also welcome direct enquiries, feel free to contact our team.

ECDIS systems already receive AIS data via the NMEA interface (IEC 61162), and VDES data will be output from the AIS unit using the same NMEA standard. In the future, ECDIS systems are also expected to support MMS via the MMTP interface, which will be made available through the Sternula MMS Proxy. 

Some maritime services use SECOM (IEC 63173-2) to secure and authenticate service data. MMS provides a dedicated SECOM Gateway, enabling SECOM-based services to be accessed through MMS – with robust and resilient transport over the Internet, VDES, and other available communication means. 

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