RTKRTK NetworkNetwork LatPosLatPos inin LatviaLatvia J. Zvirgzds GPS Network Laboratory Latvia Geospatial Information Agency, Latvia E-mail: [email protected] Agency main tasks arranges and maintains the National Geodesic Network (including the Global Positioning System (GPS) base station networks); • performs the topographical mapping of the state, including: • obtains the images of the Earth’s surface and the information of remote research; • produces orthophotomaps; • forms the digital model of the surface of the territory of the country; • compiles air navigation maps; Outline: National Geodetic Networks • Horizontal • Leveling • Gravimetric and Geoid model •RTK Network LatPOS; •Measurements in LatPos Network National Geodetic Network Designations: vector between points of 1st order vector between points of 2nd order National Leveling Network Gravimetric measurements; • Absolute gravimetric measurements in 1995 (EE, LT, LV); • Gravimetric measurements is carried out by one observer; • We are using 2 gravimeters CG-5; •We carry out regular gravimetric measurements also in our absolute gravimetric point in Rīga, in the territory of the Botanic Garden; • We intend to continue joint gravimetric measurements with Estonian, Lithuanian and Danish colleagues. GEOID LV98 LATPOS NAVSTAR (USA) LatPos GPS stations Limbaži Valmiera Ventspils Talsi Gulbene Balvi ā Oj rs Sigulda Kuld īga Madona Rēzekne Saldus Dobele Aizkraukle Liep āja Bauska Jēkabpils Prei ļi Daugavpils DOBELE Realtime LATPOS users • 19 stations 4 server computers GPRS Administrator RTK proxy / wireless Network /Cluster SPIDER WEB server server InternetInternet Site server Cluster server Firewall Spider WEB Leica SPIDER software RINEX data Administrator work space System monitoring Text and e-mail computer computer Phone for customers LatPos latency – average 10 ms From Lithuania: Leica network - from 0 to 25 ms Trimble network - 68 ms Measurements at RIGA region Control measurements on Geodetic Benchmark Ķī šezers NS 0.02 0.015 0.01 0.005 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 X koord -0.005 Y koord Meters -0.01 -0.015 -0.02 -0.025 -0.03 Measurements Control measurements on Geodetic Benchmark Geodetic Point 47 0.05 0.04 0.03 0.02 X koord Y koord Meters 0.01 0 1 2 3 4 5 6 7 8 910 -0.01 -0.02 Measurements Measurements outside Network 65km 65km 72km 25km Geodetic point 141 3rd class – base ~70 km 0.12 0.1 0.08 0.06 0.04 0.02 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 -0.02 -0.04 X koord Y koord RTK test – LatPos vs EUPOS-RIGA Receivers: Leica 1200, Trimble R8, Topcon Message: RTCM 3.0 LatPos error distribution 70 60 50 40 30 Percentage 20 10 0 -4 -3 -2 -1 1 2 3 4 CM Expierence Search for lost benchmark after construction works STRUVE ARC Point ARBIDANI GPS receivers Geodetic • Dual frequency (L1 un L2) • Modem GPRS (GSM) • 2 cm 135 Realtime Users 450 Post processing Users Single frequency GPS • Built in antena 80 cm • Geodetic antena 30 cm • Single frequency (L1) • Modem GPRS (GSM) • 50cm Future plans Rujiena Sv ētciems Kolka Gaujiena Ventspils Engure Žīguri Nītaure Kuldiga Oj ārs Dzelzava Vergale Rucava Ludza Nīgrande Valle Augstkalne Riebi ņi Vies īte Indra Medumi Conclusions 1.GNSS network speeds up measurements. 2.Next generation for local Networks - cheaper and easiest managment, realtime monitoring -accuracy - 2 cm, outside – 4cm -integer network. -crossborder cooperation 3. Develop system to receive GLONASS GALILEO, COMPASS Contacts • Latvia Geospatial Information Agency • GPS Network laboratory • +371 67064202 • +371 29259135 • [email protected] • www.latpos.lgia.gov.lv.