Exploiting the high precision capabilities of the Hellenic Positioning System - HEPOS M. Gianniou, D. Mastoris, I. Stavropoulou Geodetic Department KTIMATOLOGIO S.A. 339 Mesogion Ave., 15562 Holargos Greece Tel. +30-210-6505832, 6505828, 6505677 E-mail: mgianniu@ktimatologio.gr, dmastori@ktimatologio.gr, istavrop@ktimatologio.gr
Outline Description of HEPOS Use of RTK services Use of VRS for post-processing processing applications Prospective benefits of combined use of GPS & Galileo EGNOS and RTK applications Conclusions
Description of HEPOS Reference Stations 87 Networked Reference Stations(VRS -FKP-MAC) 11 Single Reference Stations
Description of HEPOS 98 Trimble NetRS receivers with Zephyr Geodetic antennae with radome Rack of Reference Station & the equipment of Rack HEPOS Control Center
Description of HEPOS APPLICATION Post Processing (www.hepos.gr) SERVICE RS data VRS data DATA FORMAT RINEX, CRINEX RINEX, CRINEX Real Time (GSM & GPRS supported) Network RTK: VRS RTCM 2.3 Network RTK: FKP Network RTK: MAC Single Base RTK RTCM 3.0 RTCM 3.1 CMR+ Network DGPS RTCM 2.3 Single Base DGPS RTCM 2.3
Description of HEPOS User Licenses USER LICENCES: 25/5/2009-26/2/2010 400 350 300 250 200 150 100 50 0 1/6/2009 15/6/2009 29/6/2009 13/7/2009 27/7/2009 10/8/2009 24/8/2009 7/9/2009 21/9/2009 5/10/2009 19/10/2009 2/11/2009 16/11/2009 30/11/2009 14/12/2009 # OF USER LICENCES 28/12/2009 11/1/2010 25/1/2010 8/2/2010 22/2/2010 DATE
Use of RTK services of HEPOS Use of Single-base and Network-based RTK (1.03.2008-31.12.2009) Network-based RTK (mostly the VRS technique is used) Single-Base RTK
Use of RTK services of HEPOS Use of HEPOS for measuring Ground Control Points for the production of ortho-photo maps for coast-line delineation in Greece.
Use of VRS for Post-Processing applications Use of HEPOS for the aerial surveys for the production of large scale ortho-photo (LSO) maps for Greece. LSO block HEPOS RS Specifications of aerial surveys: To ensure the correct ambiguity resolution, the horizontal distance between the airborne receiver and the reference station should not exceed 30km. Design of blocks: 40km x 42km. The locations of the (physical) Reference Stations of HEPOS were not always convenient for the flights. The solution was the use of Virtual Reference Station.
Use of VRS for Post-Processing applications Example from an aerial survey flight: The advantages of Virtual Reference Station: Can be created in the location, where it is exactly needed, ensuring small baseline vectors. Is not limited by the topography and the existence of buildings and other natural or artificial obstacles. Photo-centers Virtual Reference Station of HEPOS physical Reference Station of HEPOS
Prospective benefits of combined use of GPS & Galileo Airborne GPS data from an aerial survey Benefits of using Galileo in combination to GPS: Better satellite geometry (lower PDOP values) Easier ambiguity resolution Enhanced accuracy and reliability Confidence of availability to civilian user (Galileo is developed for civil users)
EGNOS and RTK applications The main purpose of EGNOS is to enhance positional accuracy in navigation applications. At the same time, EGNOS could be useful also for surveying applications. Currently, some techniques have been developed, which use SBAS signals (EGNOS in the case of EUROPE) to improve RTK performance. In the future, EGNOS will probably be used in various ways in a variety of positioning applications.
Conclusions The number of users investing GNSS is growing There is strong interest in high precision applications The forthcoming Galileo system is expected to contribute significantly to the performance of GNSS positioning and further increase of the GNSS users and applications
Thank you for your attention! The HEPOS project is part of the Operational Program Information Society and is co-funded by the European Regional Development Fund