Permanent GNSS Stations GNSS Global Navigation Satellite System
Permanent GNSS Stations (GNSS – Global Navigation Satellite System) Dionyssos Satellite Observatory
Must • Local Region Geology (Σταθερότητα περιοχής*) • Monument stability (Σταθερότητα κατασκευής) • Obstacle free • Interference free (Ορατότητες, >10 o) (Όχι Παρεμβολές) • Data Streaming capability (Διαδίκτυο) 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
IGS GNSS Network 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 (ETRS 89) 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 ETRS 89 shall be used for the referencing of spatial data sets in INSPIRE. Dionyssos Satellite Observatory
EUREF GNSS Network Dionyssos Satellite Observatory
EUREF in Greece NTUA DSO NOA AUTH INSU TUC Dionyssos Satellite Observatory
Station DYNG Dionyssos Satellite Observatory National Technical University of Athens - Centre national d'études spatiales Trimble Net R 9 Installed at May 2011 IGS, EUREF, REGINA networks http: //www. epncb. oma. be/_networkdata/siteinfo 4 onestation. php? station= DYNG 00 GRC https: //cnes. fr/en https: //space-geodesy. nasa. gov/docs/2011/02_REGINAhostingsitev 1_en. pdf http: //itrf. ensg. ign. fr/doc_ITRF/RT 121_POYARD_Dionysos. ITRFColocation. Survey. pdf Dionyssos Satellite Observatory
Dionyssos Satellite Observatory
DYNG Time Series Plot 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
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
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 • NTRIP : 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
NTRIP modules Dionyssos Satellite Observatory
NTRIP modules 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
IGS CASTER Real Time SSR (Ephemeris/clock corrections) streaming table products. igs-ip. net: 2101 Dionyssos Satellite Observatory
1 or 2 receivers ? Dionyssos Satellite Observatory
Positioning Techniques • Single : One receiver, acc. 2 -30 m • Relative: Two Receivers • PPP : Static acc. < 1 -2 cm DGPS acc. < 1 m Kinematic acc. < 5 cm fixed , < 20 cm float One receiver (SSR input), acc. <10 cm NTRIP 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
PPP procedure Dionyssos Satellite Observatory
Mainly used Ntrip software (open source) • BNC https: //igs. bkg. bund. de/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
Lefkada Eartquake 6. 4 W , Nov 17 2015 PPP Solution, 1 Hz, BNC/BKG 2. 5 minutes Window Station Pont ~ 5 km from EC Station Span ~ 15 km from EC 40 cm 20 cm 42 cm 35 cm 11 cm 7 cm 8 cm 5 cm 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
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