1. Permanent GNSS Stations (GNSS – Global Navigation Satellite System)
Dionyssos Satellite Observatory

2. Dionyssos Satellite Observatory
Must
Local Region Geology (Σταθερότητα περιοχής*)
Monument stability (Σταθερότητα κατασκευής)
Obstacle free (Ορατότητες, >10o)
Interference free (Όχι Παρεμβολές)
Data Streaming capability (Διαδίκτυο)
Dionyssos Satellite Observatory

3. Dionyssos Satellite Observatory
Main GNSS Networks
IGS : International GNSS Service
EUREF : European Geodetic Reference Systems
Dionyssos Satellite Observatory

4. Dionyssos Satellite Observatory

5. Dionyssos Satellite Observatory
IGS GNSS Network
Dionyssos Satellite Observatory

6. Dionyssos Satellite Observatory
EUREF
The EUREF Permanent Network (EPN) is a voluntary federation of over 100 self-funding agencies, universities, and research institutions in more than 30 European countries.
They work together to maintain the European Terrestrial Reference System (ETRS89) which is the single Europe-wide standard coordinate reference system adopted by the European Commission (ref COGI action decision F/GIS/69/EN).
In addition, the INSPIRE Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services established - among other requirements - that the ETRS89 shall be used for the referencing of spatial data sets in INSPIRE.
Dionyssos Satellite Observatory

7. Dionyssos Satellite Observatory
EUREF GNSS Network
Dionyssos Satellite Observatory

8. Dionyssos Satellite Observatory
EUREF in Greece
NTUA DSO
NOA
AUTH
INSU
TUC
Dionyssos Satellite Observatory

9. Dionyssos Satellite Observatory
Station DYNG Dionyssos Satellite Observatory National Technical University of Athens - Centre national d'études spatiales
Trimble Net R9
Installed at May 2011
IGS, EUREF, REGINA networks
Dionyssos Satellite Observatory

10. Dionyssos Satellite Observatory

11. Dionyssos Satellite Observatory
DYNG Time Series Plot
Dionyssos Satellite Observatory

12. Dionyssos Satellite Observatory
Greek Velocity Field DSO contribution to EUREF densification; status and future steps EUREF Analysis Centres Workshop, Royal Observatory of Belgium, October 2017
Dionyssos Satellite Observatory

13. Dionyssos Satellite Observatory
Global Data Centers
Global Data Centers are the main interfaces to the Analysis Centers and the user community in general. 
They receive/retrieve, archive, and provide online access to tracking data provided by the Operational/Regional Data Centers.  At a minimum, Global Data  Centers  archive 30-second  sampling  interval data  from  IGS sites identified as reference frame stations.
The Global Data Centers also archive and provide online access to IGS products (orbits, clocks).
Finally, the IGS Global Data Centers backup and secure their holdings of IGS data and products, exchanging data between other data centers in order to ensure equalization of data holdings.
Dionyssos Satellite Observatory

14. Dionyssos Satellite Observatory
Global Data Centers
Institution Abbreviation Country
Wuhan University WHU China
Institut Geographique National IGN France
Korean Astronomy and Space Science Institute KASI Korea
European Space Agency / ESAC ESA / ESAC Spain
Crustal Dynamics Data Information System CDDIS United States
Scripps Institution of Oceanography SIO United States
Dionyssos Satellite Observatory

15. NTRIP protocol for streaming Differential GNSS data over the Internet
Networked Transport of RTCM via Internet Protocol
RTCM : Radio Technical Commission for Maritime Services
Released in September 2004
developed by
German Federal Agency for Cartography and Geodesy (BKG)
Dortmund University Department of Computer Science
- GNSS Data segment
Collecting & streaming GNNS data
- SSR (State Space Representation) segment
Computing & streaming SSR (ephemeris/clock corrections)
!!!! REAL TIME !!!!
Dionyssos Satellite Observatory

16. Dionyssos Satellite Observatory
NTRIP modules
Dionyssos Satellite Observatory

17. Dionyssos Satellite Observatory
NTRIP modules
Dionyssos Satellite Observatory

18. Dionyssos Satellite Observatory

19. Dionyssos Satellite Observatory
EUREF CASTER Real-Time GNSS Data Streams From EUREF-IP Ntrip Broadcaster
Dionyssos Satellite Observatory

20. Dionyssos Satellite Observatory
IGS CASTER Real Time SSR (Ephemeris/clock corrections) streaming table products.igs-ip.net:2101
Dionyssos Satellite Observatory

21. Dionyssos Satellite Observatory
1 or 2 receivers ?
Dionyssos Satellite Observatory

22. Positioning Techniques
Single : One receiver, acc. 2-30m
Relative: Two Receivers
Static acc. < 1-2 cm
DGPS acc. < 1m
Kinematic acc. < 5cm fixed , < 20cm float
PPP : One receiver (SSR input), acc. <10cm
NTRIP
Dionyssos Satellite Observatory

23. Dionyssos Satellite Observatory
RTK vs. PPP
RTK: “Tell me the precise location of your reference station and I will tell you the precise location of your mobile receiver.” 
PPP: ”Tell me the precise location of the navigation satellites and I will tell you the precise location of your mobile receiver.”  
Static (with precise orbits) does both !
Dionyssos Satellite Observatory

24. Dionyssos Satellite Observatory
PPP procedure
Dionyssos Satellite Observatory

25. Mainly used Ntrip software (open source)
BNC
pros : extremely accurate PPP
cons : only PPP, not so user friendly
RTKLib
pros : user friendly environment, DGPS, RTK,PPP
cons : not so accurate real time PPP
Dionyssos Satellite Observatory

26. Dionyssos Satellite Observatory
Lefkada Eartquake 6.4 W , Nov PPP Solution, 1Hz, BNC/BKG 2.5 minutes Window
Station Pont ~ 5km from EC Station Span ~ 15km from EC
11cm
7cm
40cm 20cm
42cm
35cm
8cm
5cm
Dionyssos Satellite Observatory

27. Dionyssos Satellite Observatory
Other Links
PPP-Wizard project
Precise Point Positioning at BKG
Orbits & Clock corrections
Dionyssos Satellite Observatory

28. BNC PPP in progress Station LAMY at NTUA (click on image to play)
Dionyssos Satellite Observatory