1. EGNOS Ionosphere Related Activities S. Schlüter, R. Prieto-Cerdeira
SBAS IWG New Delhi 05-07/02/2014

2. Topics EGNOS V2.x.x Ionosphere Related Activities
EGEP Ionosphere Related Activities:
EGNOS V3
EGEP Activities for the Characterization of the Ionosphere
Activities with African Countries and External Partners
Status/Way forward

3. EGNOS V2 Release Road Map
V2.2ext
Qualified :June 2008
Certifiable release
V2.3.1p
Qualified: December 2011
Features: New RIMS (Alexandria, Athens, La Palma), NLES adaption to Inmarsat-4, Block IIF inclusion, Service coverage extension, migration to MPLS network technology, MT9/MT17 Coherency …
V2.3.1i
Qualified: July 2012
Features: Improved robustness to severe Iono activity ...
2.3.2
Qualified: August 2013
Features: New RIMS (Agadir, Abu Simbel), Optimisation of iono algorithms, Robustness against PRN 25 clock drift feared event (Bergen), Leap second anomaly correction (deployed in 2012) …
V2.4.1M
Qualified: ~July 2014
Features: Obsolescence resolution (CCF, NLES and EWAN), Qualification of ASTRA Sirius 5, New Missions (LPV-200, MOPS-D), Tuning of Iono processing …
V.2.4.1P
Qualified: ~ Mid 2015 (Procurement On-going)
Features: Introduction of new ASTRA, 1 Step of Iono working activities, …
V2.4.2
KO march 2014
Features: CPF obsolescence, RIMS A,B,C obsolescence, RIMS L2C capability, GEO ranging, 2 Step of Iono working activities

4. EGNOS V2 IONO Objectives
Objectives of V2 Ionospheric Work Packages:
General focus of all activities is to improve availability in front of severe solar max ionospheric conditions
Minor changes/tuning related to some workarounds implemented in the past
V2.4.2 considers also major algorithmic changes in the CPF

5. EGEP/EGNOS V3 Ionosphere Related Activities
Main Objectives of EGEP/EGNOS V3 IONO Activities:
Improving of Means/Tools to support development EGNOS V3 (and V2 releases)
Improving/Consolidation of Means/Tools for the future qualification of EGNOS V3
Improving of Means/Tools to support other SBAS activities, e.g. Africa
Means/Tools are:
Characterization of the ionosphere (Indicators of Ionosphere Activity, Specifications, …)
Reference Models for performance assessment and qualification
Data (particular focus on: Africa, scintillations)

6. Definition of an Indicator of Ionospheric Activity
Along-Arc TEC Rate (AATR) indicator as the hourly Root Mean Square (RMS) of “weighted” Along-Arc Vertical TEC Rate.
Where Dt can be 30 or 60 seconds
Comments:
The RMS of all the AATRs (all the satellites) during 1 hour is computed for a given receiver, in order to mitigate spurious values of AATR.
With the squared mapping, we mitigate the effect worst VTEC computed at low elevation.
Stations used for AATR RMS computation
15 November, 2018
The European GNSS Programmes

7. Generation of Ionospheric Reference Scenarios
CDF of AATR RMS
(Different for 3 Geomagnetic Regions)
Requirement
3D Iono Model
AART RMS
Selection of periods and data
Reference
Scenarios
RDG

8. Developed Scenarios

9. Scintillation Performance Analysis
Separate Receiver effects from System effects

10. Scintillation Specifications (preliminary)

11. Receivers & Product Data
EGEP ID 66: MONITOR II
Core for future EGNOS Iono related activities
Launch of activity: March 2014
Users
Contributing
Receivers & Product Data
MONITOR II
IONO Repository & Products
Processing
EGNOS V2 & V3 Projects
Testbeds
GALILEO Project
CNES
Others..
ASECNA Project
Laboratories
CNES
DLR
ICASES I & II
Others…

12. MONITOR II Products Examples:
Bitgrabber data to replay selected scintillation events
GNSS observations (Ranges and Scintillation)
TEC maps
Scintillation Occurrence maps
AATR RMS
Ad hoc generation of ionospheric reference scenarios
Upgrades of Iono Modelling (GISM, NeQuick)
VTEC map plot associated to VTEC-TOMION UPC external products (240 IGS stations) Latency : 1 < < 2 days

13. MONITOR: Ionospheric Experimental Station Network
Central Archiving and Processing Facility

14. Activities with African Countries and External Partners
ESA/CNES Activities with ASECNA
Collaboration with SANSA
SAGAIE network
Collaboration with additional partners TBD at next IONO SBAS meeting
Air Traffic Control Agency ASECNA (Agency for Aerial Navigation Safety in Africa and Madagascar)

15. SAGAIE: Two Stations Architectures
Architecture 1: Dakar, Lomé
FLEXPAK6 Novatel Rx, GPS GLO GAL
data Collection
PolarXS Septentrio Receiver,
GPS, GLO, GAL data collection
and scintillations parameters
Archive all raw data measurements,
Rinex it, and send it to Toulouse
Bitgraber : 2XUSRPN200 for RF signal recording
Architecture 2: Douala, Ouagadougou, Ndjamena

16. Data Flow between ASECNA/SAGAIE Network and MONITOR CPF
CNES SAGAIE
Stations
ESA MONITOR
ASECNA
High Quality Multi-GNSS
Receiver Network
Stations raw
Data
FTP
Server
Data archiving
CNES
External data flow
Rinex 3
+ ISMR data
High level iono Products
ESA/MONITOR

17. DAIS
Data Assimilation Techniques for Ionospheric Reference Scenarios (DAIS) Aiming to generate improved EGNOS Ionospheric Reference Scenarios by combining spaceborne and ground-based GNSS observations.
Development of a method for combined reconstruction of the ionosphere (Ground & Space GNSS & Model)
Filling of data gaps, in particular in African low latitudes and over oceans.
Improved modelling of the Crest (profile, HmF2 and FoF2)

18. Status On-going & Future Activities:
On-going activities to further improve and optimize GIVD/GIVE related algorithms in EGNOS V2 releases
Preparation of EGNOS V3 Phase C/D (Refinement and consolidation of tools and specifications)
Further development of Models and Tools with a strong focus on scintillation effects
MoU for Collaboration of ASECNA, ESA and CNES to be signed in February
SANSA agreed to host 2 stations in Namibia (Implementation: Mid 2014)
Increase of cooperation with external partners for data exchange and coordinated actions in support of EGNOS-V3 and SBAS-Iono group.
(E.g. Boston College (LISN in South America, SCINDA and other initiatives in Africa), ASECNA (various locations in Africa), SANSA (South Africa), CHAIN (Canada), JRC-ISPRA (various locations).

19. Many Thanks for Your Attention!

20. SAGAIE MAIN FEATURES
SAGAIE = STATIONS ASECNA GNSS for ANALYSE of the IONOSPHERE EQUATORIALE
CNES and ASECNA have decided in 2012 to deploy a GNSS data collection network in Sub-Saharian area for ionosphere characterization
Cooperation agreement signed between ASECNA and CNES in 2012
CNES in charge of: Overall management, engineering, equipment's procurement and sites deployment
ASECNA in charge of: sites hosting, Telecom network, and stations operations
CNES has contracted Thales for stations AIV and for sites deployment
Five sites were selected: Dakar, Lomé, Douala, Ouagadougou and N’Djamena
Dakar and Ouagadougou are actually operational (deployed in May/June 2013)
Douala Lome and Ndjamena will be deployed in July 2013

21. Step 1 service area – for analysis during Phase B

22. Station at Ouagadougou Airport
Choke Ring antenna
Novatel Rx
Switch
Fuse
Server for monitoring and control
Control Tower

23. Correlation coefficient between the RMS of the post-fit residuals of a ionospheric model and other indices: Local Time (LT), AATR, DST, Ap and Solar Flux (SF).
RECEIVER
LAT (Deg)
Correlation (x 100) LT
AATR
DST Ap SF
REYK 64 18 70
-25 30 27
ONSA 57 10 78
-33 35 13
POTS 55 11 83
-29 20
CAGL 37 26 74
-13
MAS1 47 72 -7 7 9
NKLG 52 69
-24
Associated to
Solar terminator
High latitude receivers are more affected by geomagnetic activity
The study includes six different receivers (see map) during some tens of days with high ionospheric activity (all days with DST<-100nT are included). 23

24. GEO Roadmap – Satellite view

25. Iono Scintillation, Effects on SBAS
In SBAS systems ionospheric scintillations shall be considered for their effects in the following:
System level:
Loss-of-lock (SNR) of GNSS satellites at system (RIMS) level
Increase number of cycle-slips at (RIMS) system level
Increased code-phase and carrier-phase noise at (RIMS) system level
User level:
Loss-of-lock of GEO or MEO
SBAS Data demodulation errors
Cycle-slips
Increased code-phase and carrier-phase noise (integrity to be protected?)