Permanent GNSS Stations GNSS Global Navigation Satellite System

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

Must • Monument stability • Obstacle free • Interference free • Data Streaming capability Dionyssos Satellite Observatory

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

EUREF GNSS Network Dionyssos Satellite Observatory

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

Station (DYNG) at Dionyssos Satellite Observatory (NTUA-CNES) Trimble Net R 9 Installed at May 2011 IGS, EUREF, REGINA networks 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

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

NTRIP modules Dionyssos Satellite Observatory

NTRIP modules 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 : 2 Receivers Static acc. < 1 -2 cm DGPS acc. < 1 m Kinematic acc. < 5 cm fixed , < 20 cm float • PPP : 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

Other Links • PPP-Wizard project http: //www. ppp-wizard. net/index. html • Orbits & Clock corrections https: //igs. bkg. bund. de/ntrip/orbits Dionyssos Satellite Observatory

BNC PPP in progress Station LAMY (Lambadario) Dionyssos Satellite Observatory