Frequently Asked Questions about

AIS 2.0/VDES (VHF Data Exchange System)


  • AIS 2.0 or VDES?

AIS 2.0 is the commercially used name, and VDES (VHF Data Exchange System) is the technical term, just like your mobile phone, it perhaps uses 4G, but the technical name is Long-Term Evolution (LTE).

  • What is the difference between AIS and AIS 2.0?

AIS is a one-way digital exchange of identity, position, etc. It has been a global standard since 2001 (ITU-R M.1371-1) and has been a SOLAS requirement since 2001. AIS 2.0 (VDES) is a two-way digital exchange of data. It is a global standard from 2022 (ITU-R M.2092-1) and is about to become a SOLAS requirement, expected from 2026.

  • What is the unique feature of using AIS 2.0 compared to the other satellite systems?

AIS 2.0 is designed to transfer data without an IP address. This allows digital communication to the bridge shipment as no IP address is equal to an unbreakable firewall. Remote log-in is simply not possible. The currently available satellite communication systems make use of an IP address when transferring data. 

  • Why Sternula is leading in VDES technology?

Sternula has more than 10 years of experience in developing and standardizing VDES technology. Our CTO is a chairman of IALA E-Nav WG3 and we are the co-founder of the VDES Alliance. Furthermore, Sternula is the first and only commercial satellite operator of AIS 2.0 (VDES).

  • Does Sternula offer global coverage?

Yes, Sternula offers global coverage. Our satellite is flying a polar orbit route and visits every place on Earth twice a day. In the future Sternula will have more satellites providing better and more frequent coverage.

  • Why is AIS 2.0 relevant for the maritime authorities and the vessel?

The AIS 2.0 enables IMO e-Navigations strategy implementation plan to digitize 15 obligated services from the maritime authorities to the ships.


VDE-SAT is VDES transmitted through a satellite, such as Sternula-1.

VDE-TER is terrestrial VDES, transmitted by the ground stations on shore.

  • How can maritime authorities benefit from the use of VDE-SAT technology?

Using VDE-SAT, maritime authorities can provide their obligated services to ships in the full EEZ area. The VDES satellite provides a broad area coverage. VDES satellite can also cover areas beyond the range of terrestrial VDES, or where VDES infrastructure does not exist.

  • Is ship-to-ship communication possible?

Yes, there are two options: either through line-of-sight direct communication or using a satellite connection.

  • Can you avoid spoofing with AIS 2.0?

No, however with a 30 times higher data rate than AIS, it will be possible to add a digital signature while transmitting the identity of a ship. This makes the information the sender is sending out trustworthy. The use of digital signature is a part of IALA guidline G1117-1 MCP. If interested in MCP, please contact us.

  • Which equipment should be installed to receive messages through VDES?

You need a AIS/VDES transceiver, designed and tested to IEC 61933-2 and future ITU-R M.2092-1 as applicable. We recommend installing the Sternula MMS Proxy as well.

  • Will AIS be obsolete?

No. The new AIS 2.0/VDES transceiver will consist of AIS/ASM and VDES/AIS 2.0. It will still be used alongside AIS as 3G and 4G or 4G and 5G are used alongside each other.

  • What is the latency?

It depends on where in the world you are. Contact us for more information.

  • Which frequency does AIS 2.0 use?

VDES frequency usage is illustrated according to M2092-2 of the ITU-R M.2092-1 recommendation document.

  • Can you transmit data from ship to shore using VDES?

Yes, you can transmit through either VDE-SAT or VDE-TER.

  • What is the data rate sent through VDES (AIS 2.0)?

Data package limit to 100kB. Enough to send weather bulletins, ice charts, etc.

  • What is the coverage area of VDE-SAT?

About 1000 km radius.

  • How often does the satellite visit my area?

It depends on the latitude. See the 10-day predictions for your location here.

  • Can you communicate via voice or video using VDES?

No, the available communication forms are text-based.

  • Can the broadcasted data (for example S-412 weather bulletin) by VDES be displayed on the ECDIS?

Yes, since the technology is designed without an IP address, however, it depends on the ECDIS provider and the data format S-100.

  • Where can I read more about AIS 2.0(VDES)?

IALA guideline.

  • Will Sternula support the CML VDES 1000?

Yes. Sternula and CML have a cooperation through the VDES Alliance to integrate the equipment of CML to work with Sternula-1.

  • Will Sternula’s MMS support roaming between VDE-TER, VDE-SAT and 4G?

Our demonstration projects support the roaming of MMS traffic over mobile networks (3/4G), Saab R60 VDE-TER and Saab R6 VDE-TER and VDE-SAT.

  • Will Sternula support the IALA G1117 Virtual AtoN via VDE-SAT service?

In our cooperation with Saab R6, we target to demonstrate the virtual AtoN via VDE-SAT service as described in IALA G1117 in the future.

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