About EGNOS SoL assisted service for Maritime Users (ESMAS)

Satellite based Augmentation System (SBAS), as the system providing wide area or regional GNSS augmentation, is recognized by IALA as an Aid to Navigation (AtoN). Thus, EGNOS as the European SBAS, provides the EGNOS Safety of Life (SoL) assisted service for Maritime Users (ESMAS) GPS augmentation service to enable maritime navigation for SOLAS operations.


ESMAS, being declared in March 2024 as the first worldwide SBAS service tailored to maritime users, currently improves GPS performances by augmenting the L1 C/A signal with the provision of corrections and integrity information for positioning and navigation applications over Europe. The broadcast of these corrections and integrity information is done through the Signal-in-Space (SiS) transmitted by GEO satellites.


The augmentation provided by ESMAS to GPS contributes to maritime navigation in line with the operational requirements of IMO (Resolution A.1046(27)) and enables mariners to achieve the required accuracy and integrity performance levels for the navigation both in ocean and coastal waters, harbour entrances and harbour approaches.


The use of ESMAS requires a type approved shipborne receivers (certified according to IEC 61108-7 standard for SBAS L1 receiver equipment) taking advantage of both the GPS Standard Positioning Service (SPS) broadcast signal and EGNOS messages to compute an enhanced positioning and navigation solution with navigational status indications to support a safe navigation.


ESMAS provides guarantees on the SBAS messages (at SiS level), not taking responsibility for the local environment impact at user level. Thus, ESMAS offers service (SiS) level commitments and typical performance based on EGNOS historical data, but no commitments on position domain performances.


In addition to the above, ESMAS provides Maritime Safety Information (MSI) proposals as a warning message to communicate any planned or unplanned outages in the service, in line with the IHO’s WWNWS13 – 2021. Thereby, the ESMAS service provider sends ESMAS MSI proposals to the relevant NAVAREA coordinator, who is ultimately responsible for disseminating the final MSI navigational warnings.