The status of implementation.

1. The status of implementation
EGNOS based solution for
the French DGPS network

2. What is DGPS in maritime ?
 Usually called IALA beacon stations
 Shore-based service (283,5 to 325 KHz)
 International interoperability
 Improve accuracy
 Ensure Integrity
 Contribute to IALA1 WWRNP
CONTEXT
1 International association of marine Aids to navigations and Lighthouse Autorithies

3. Legacy French network
 7 stations
 Central monitoring
 Old low rate WAN
 No changes since 90’s
 No redundancy at station
 Availability decreasing
CONTEXT

4.  Discussed within IALA PNT WG
 Accuracy measurements:
 DGPS French IALA Beacon
 GPS standalone
 GPS corrected by EGNOS SiS
 GPS corrected by EGNOS based RTCM converted from
EGNOS RTCA EDAS stream (VRS for Pont de Buis)
Note: 33 Km distance from the station to the rover
PRELIMINARY STUDIES
IS EGNOS A GOOD CANDIDATE FOR
MARITIME DGPS MODERNISATION ?

5. FULL SCALE
DEMONSTRATOR
Architecture description
 Several possible architectures to use EGNOS
 Both EGNOS SiS ans EDAS
 Centralised/Decentralised
 IALA Guideline G1129 (The Retransmission of
SBAS Corrections Using MF-Radio Beacon and
AIS)
 Centralised architecture selected
 Implemented on a real French IALA Beacon
station (Olonne, ID464)

6. FULL SCALE
DEMONSTRATOR
Central Server Software
 Beacon.net (Alberding GmbH)
 Host in French government central IT
facilities
 Implement the VRS concept
 Configure the RTCM streams generation
for any location of the EGNOS coverage
 Perform integrity checked

7. DGPS Station: MSK Modulator
 Developped by ACTRIS company to fit specific
maritime DGPS requirements.
 Comply with ITU M823-3
 Ability to deal with two sources of RTCM
 Broadcast autonomously a RTCM message 6 in
case of corrections unavailability
 Possibility to recover RTCM streams remotely
for logging (i.e injuries situation)
 IP enabled, Web monitoring & remote set-up
FULL SCALE
DEMONSTRATOR

8. Results
Availability : >99,8% IMO A1046 requirement)
 February, 15th to March, 15th 2018 – Central server side (beacon.net) - 99,86%
 July 2018 – User side (DGPS French Control Center Belle-île en mer) - 100%

9. Results
Local GPS/DGPS Antenna
Position Accuracy 0,01m
MF Signal
GPS
Accuracy
 The local GPS/DGPS Antenna set nearby the
MF station
 The GPS/DGPS receiver compute both GPS
standalone and EGNOS over DGPS corrected
positions
 Accuracy around 1m at Belle-île control
center (150 Km from the station)
FFM_SABL: EGNOS over DGPS
RAW_SABL: GPS standalone

10. Results
Integrity
 Pre-broadcast integrity monitoring (PBM) thresholds (on Beacon.net) compliant with IALA
Guideline 1112 – Performance and Monitoring of DGNSS Services in the Frequency Band 283.5-
325kHz
 No integrity warnings occurred during the period
 Pre-broadcast monitoring sensitivity was successfully tested by decreasing thresholds in order to
generate warnings

11. Cost-Based Analysis
 Costs assessment (per DGPS station)
 To be also considered :
 Less equipment maintenance costs (centralised architecture)
 High reliable network subscription needed (new charge for the service provider)
Cerema CBA GSA
Traditionnal DGPS (no redundancy) 150 K€ 133 K€
EDAS-Centralized 20 K€ 27 K€

12. Conclusion
Towards an operational service
 Compliance of the EDAS centralised solution
 Reduction of the overall costs for the provider
 Official Commissioning of the first French station
will come early 2019
 More stations equipped during 2019
 Possible local backup solution under reflexion
(EGNOS SiS based with a local receiver)

13. Thank you !
Etienne LEROY
Etienne.leroy@cerema.fr
+33 2 98 05 67 50