551
1 INTRODUCTION
Satellite Based Augmentation Systems (SBAS) are
designed to augment global navigation system
constellations by broadcasting additional signals from
geostationary (GEO) satellites. The basic scheme is to
use a set of ground monitoring stations to receive
GNSS signals that are processed in order to estimate
satellite (position and clock) and ionospheric errors
which are also applicable to users within the service
definition area. Once these estimations have been
computed, they are broadcast in the form of
“differential corrections” by means of SBAS
geostationary satellite(s). Some integrity data are also
broadcast along with these correction messages for the
GNSS satellites that are in the view of this network of
monitoring stations what increases the confidence that
a user can have in the satellite-based positioning
solution.
Figure 1.SBAS architecture
EGNOS is the satellite-based positioning service
over Europe which provides better accuracy with
respect to GPS standalone position. In addition,
EGNOS provides Integrity, which can be suitable for
safety critical applications in the maritime sector.
EGNOS Performance Along Finnish Coast
R. González
1
, E. Lacarra
1
, M. López
2
& K. Heikonen
3
1
EGNOS Satellite Services Provider, Madid, Spain
2
European GNSS Agency, Prague, Czech Republic
3
Finnish Transport Infrastructure Agency, Helsinki, Finland
ABSTRACT: The purpose of this article is on one side to inform Maritime community about the ongoing
activities adopted for the provision of EGNOS (European Geostationary Navigation Overlay Service) L1
maritime service and IEC standardisation process to produce a new IEC (International Electrotechnical
Commission) standard for SBAS maritime receivers and on the other side, to demonstrate the benefits of the
SBAS system in Europe, EGNOS (European Geostationary Navigation Overlay Service) in high latitudes to
Maritime community.
http://www.transnav.eu
the International Journal
on
Marine Navigation
and Safety of Sea Transportation
Volume 15
Number 3
September 2021
DOI: 10.12716/1001.15.03.07
552
2 EGNOS L1 MARITIME SERVICE
The European Commission, EC (EGNOS owner), the
GNSS Agency, GSA (EGNOS Services Programme
Manager), the European Satellite Services Provider,
ESSP (EGNOS service provider) and the European
Space Agency, ESA (EGNOS design agency) are
working in close collaboration to provide an EGNOS
L1 maritime service for “Harbour entrances, Harbour
approaches and Coastal waters” and for “Ocean
Waters” over Europe.
The EGNOS L1 Maritime service aims at providing
pseudo-range corrections, associated ranging integrity
and alert information to GPS L1 signals to let
shipborne receivers compute an enhanced navigation
solution with respect to GPS standalone, meeting
operational requirements included in in the IMO
Resolution A.1046 (27) for maritime navigation in
ocean waters, harbour entrances/approaches and
coastal waters over European coastal and inland
waters. EGNOS L1 Maritime service is planned by
2023 when the IEC SBAS test standard is expected to
be ready. The service will include performance
monitoring reporting and provision of Maritime
Safety Information (MSI) as well.
EGNOS L1 performance (accuracy, availability,
continuity, integrity, time to alarm, coverage) was
analysed concluding that EGNOS L1 meet the
operational requirements stated in International
Maritime Organization (IMO) Resolution A.1046 (27)
for “Harbour entrances, Harbour approaches and
Coastal waters” and for “Ocean Waters” over Europe.
Assessment is ongoing to define the potential servicer
area for the EGNOS L1 maritime service, which plans
to cover most of European coast and inland waters.
Moreover, GNSS campaigns on board vessels (such as
the one presented in section 6 of this paper) along
European coasts have been carried out to demonstrate
the EGNOS benefits in real environmental conditions
and potential and common vessels.
The service provision scheme required to
guarantee the required service level is under
definition, and was presented in the European
Maritime Radionavigation Forum (EMRF) to maritime
authorities. This service plans to include an EGNOS
Maritime Safety Information (MSI) service to mariners
and a potential establishment of specific working
agreements between the EGNOS Service Provider and
any national competent authority.
In addition, vessels should be equipped with type
approved receivers for SBAS L1 in order to ensure the
required operational performance for maritime
community. For that, EC requested CEN / CENELEC
to support the development of a test standard
regarding SBAS L1 receivers for maritime
applications, which will be covered in a new part
standard in IEC 61108 series. The IEC standardisation
process has started in February 2020, and is expected
to be completed by 2023.
3 SBAS STANDARDISATION FRAMEWORK FOR
SHIPBORNE RECEIVERS
Currently, IALA G-1152, [2], states that “IMO
recognises GNSS as part of World Wide Radio
Navigat