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

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

Dionyssos Satellite Observatory Main GNSS Networks IGS : International GNSS Service http://www.igs.org/ EUREF : European Geodetic Reference Systems http://www.euref.eu/ Dionyssos Satellite Observatory

Dionyssos Satellite Observatory

Dionyssos Satellite Observatory IGS GNSS Network Dionyssos Satellite Observatory

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 2003 - 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

Dionyssos Satellite Observatory EUREF GNSS Network Dionyssos Satellite Observatory

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

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 http://www.epncb.oma.be/_networkdata/siteinfo4onestation.php?station=DYNG00GRC https://cnes.fr/en https://space-geodesy.nasa.gov/docs/2011/02_REGINAhostingsitev1_en.pdf http://itrf.ensg.ign.fr/doc_ITRF/RT121_POYARD_DionysosITRFCo-locationSurvey.pdf Dionyssos Satellite Observatory

Dionyssos Satellite Observatory

Dionyssos Satellite Observatory DYNG Time Series Plot Dionyssos Satellite Observatory

Dionyssos Satellite Observatory Greek Velocity Field DSO contribution to EUREF densification; status and future steps EUREF Analysis Centres Workshop, Royal Observatory of Belgium, 25-26 October 2017 Dionyssos Satellite Observatory

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

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

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

Dionyssos Satellite Observatory NTRIP modules Dionyssos Satellite Observatory

Dionyssos Satellite Observatory NTRIP modules Dionyssos Satellite Observatory

Dionyssos Satellite Observatory

Dionyssos Satellite Observatory EUREF CASTER Real-Time GNSS Data Streams From EUREF-IP Ntrip Broadcaster www.euref-ip.net:2101 Dionyssos Satellite Observatory

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

Dionyssos Satellite Observatory 1 or 2 receivers ? Dionyssos Satellite Observatory

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

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

Dionyssos Satellite Observatory PPP procedure Dionyssos Satellite Observatory

Mainly used Ntrip software (open source) BNC https://igs.bkg.bund.de/index/index pros : extremely accurate PPP cons : only PPP, not so user friendly RTKLib http://www.rtklib.com/ pros : user friendly environment, DGPS, RTK,PPP cons : not so accurate real time PPP Dionyssos Satellite Observatory

Dionyssos Satellite Observatory Lefkada Eartquake 6.4 W , Nov 17 2015 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

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

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