1. E. Brockmann EGS Nice, April 2002 Applications of the real-time Swiss permanent GPS network 'AGNES' E. Brockmann, S. Grünig, R. Hug, D. Schneider, A.Wiget and U. Wild elmar.brockmann@lt.admin.ch www.swisstopo.ch

2. E. Brockmann EGS Nice, April 2002 Contents AGNES network –History –Stations –Concept Conclusions Applications –Surveying –Geodynamics –Meteorology –Positioning Conclusions Positioning GPS meteo Geodynamics AGNES net

3. E. Brockmann EGS Nice, April 2002 History 1989-1992: GPS based first order network (104 sites) Accuracy: 0.5 - 1.0 cm horizontally 2.0 - 3.0 cm vertically 1995: Definition of CHTRS95 (equal ETRS89 at epoch 1993.0) Conclusions Positioning GPS meteo Geodynamics AGNES net Swiss first order network (1989-1992)

4. E. Brockmann EGS Nice, April 2002 History (2) 1998: re-measuring of LV95 (CHTRF98); differences below < 1 cm horizontally and < 3 cm vertically 1998: Start of the project with 8 permanent stations 2001: Completion with 29 permanent stations Conclusions Positioning GPS meteo Geodynamics AGNES net

5. E. Brockmann EGS Nice, April 2002 AGNES stations Conclusions Positioning GPS meteo Geodynamics AGNES net

6. E. Brockmann EGS Nice, April 2002 AGNES network 29 stations Density of 50 km Positioning Reference frame Scientific – GPS meteo – Geodynamics Applications Conclusions Positioning GPS meteo Geodynamics AGNES net

7. E. Brockmann EGS Nice, April 2002 AGNES network (2) PNAC Monitor computer LAN SWISSTOPO AGNES- Station 1 Communication computer Access server GSM WWW server Internet AGNES- Station 2 AGNES- Station... AGNES- Station 21 LAN BIT Firewall Federal Net Public Net KOMBV Real-time Positioning Post-Proc. Positioning Scientific Applications Reference frame Geodynamics GPS meteo Conclusions Positioning GPS meteo Geodynamics AGNES net “Daily /hourly” “Second”

8. E. Brockmann EGS Nice, April 2002 AGNES data flow GSM LAN BIT Communication computer User position (NMEA) Access server RTCM [Version 2.2] ISDN primary connection 0900-Service 0900-55 00 50 Initialization ! Firewall Conclusions Positioning GPS meteo Geodynamics AGNES net

9. E. Brockmann EGS Nice, April 2002 AGNES GPS equipment Trimble 4000SSi, Trimble 4700 and Leica System 530 receivers Different antenna types (Choke Ring, Microcentered L1/L2, Zephyr), no radomes Individual antenna calibration (relative to “Choke” Ring and “Geodetic” antenna) Conclusions Positioning GPS meteo Geodynamics AGNES net

10. E. Brockmann EGS Nice, April 2002 Surveying First order network and densification campaigns are integrated in the permanent network Advantages: –Fewer neighboring sites to be measured (only 1 control site instead of 3 neighboring sites) –Better integration due to time series of the reference stations Conclusions Positioning GPS meteo Geodynamics AGNES net

11. E. Brockmann EGS Nice, April 2002 CHTRF 98 CHTRF 98 Teil 1 CHTRF 98 Teil 2 CHTRF 98 Teil 3 LHN95 Emmental LHN95 Sustenpass Luzern 99 Bern 99 Saas Fee 99 Surveying Conclusions Positioning GPS meteo Geodynamics AGNES net

12. E. Brockmann EGS Nice, April 2002 Geodynamics Permanent Network Analysis Center (PNAC) at the Swiss Federal Office of Topography (swisstopo) Automated processing of all AGNES stations + 19 European tracking stations (contribution to EUREF and reference frame maintenance in Switzerland) EUREF EUREF + AGNES Conclusions Positioning GPS meteo Geodynamics AGNES net

13. E. Brockmann EGS Nice, April 2002 Results updated daily / weekly : –Coordinates/Covariance (SINEX format) –Troposphere parameters (SINEX format) –Time series, velocity fields PNAC products http://www.swisstopo.ch/geoaktuell/en/pnac.htm Conclusions Positioning GPS meteo Geodynamics AGNES net

14. E. Brockmann EGS Nice, April 2002 Time series: Zimmerwald (ZIMM) 2 cm Conclusions Positioning GPS meteo Geodynamics AGNES net

15. E. Brockmann EGS Nice, April 2002 Time series: Bolzano (BZRG) Earthquake in Northern Italy, July 15, 2001 15:06 UTC, Magnitude: 4.8 2 cm ? Antenna change Conclusions Positioning GPS meteo Geodynamics AGNES net

16. E. Brockmann EGS Nice, April 2002 Time series: Samedan (SAME) 2 cm ? ? Conclusions Positioning GPS meteo Geodynamics AGNES net

17. E. Brockmann EGS Nice, April 2002 Velocity field in ITRF00 (rel. ZIMM) Velocities for sites with time series > 0.5 years Conclusions Positioning GPS meteo Geodynamics AGNES net

18. E. Brockmann EGS Nice, April 2002 Alpine network Collaboration of BKG, OLG, CNRS, IGN, UPAD, LPT for deriving a dense Alpine dynamic model Conclusions Positioning GPS meteo Geodynamics AGNES net

19. E. Brockmann EGS Nice, April 2002 Excursion: Antenna calibrations L2 North Microcentered antenna (w.r.t IGS values) Conclusions Positioning GPS meteo Geodynamics AGNES net

20. E. Brockmann EGS Nice, April 2002 Antenna calibrations (2) Elev.-dep. corrections Microcentered antenna Conclusions Positioning GPS meteo Geodynamics AGNES net

21. E. Brockmann EGS Nice, April 2002 Impact of individual antenna models Zimm: Choke Ring -1.0 mm North 2.5 mm Up 2.5 mm East STAB: Zephyr -0.5 mm North -8.0 mm Up 1.5 mm East Conclusions Positioning GPS meteo Geodynamics AGNES net

22. E. Brockmann EGS Nice, April 2002 GPS meteorology Partners in Switzerland : –MeteoSwiss –University of Berne (IAP) –Swiss Federal Institute of Technology (ETH) Zurich –COST 716: Exploitation of ground-based GPS for climate and numerical weather prediction applications Conclusions Positioning GPS meteo Geodynamics AGNES net

23. E. Brockmann EGS Nice, April 2002 Hourly processing Since Dec. 2001 50 sites: – 21 EUREF – 29 AGNES Conclusions Positioning GPS meteo Geodynamics AGNES net Near real-time results of 6 centers at KNMI: http://www.knmi.nl/samenw/ cost716/

24. E. Brockmann EGS Nice, April 2002 movie.htm 24-hour ZTD movie Conclusions Positioning GPS meteo Geodynamics AGNES net

25. E. Brockmann EGS Nice, April 2002 Numerical weather prediction tests Integrated water vapor field (Sep. 10, 2001; 15:00 UTC) Without GPSGPS assimilatedDifference Conclusions Positioning GPS meteo Geodynamics AGNES net

26. E. Brockmann EGS Nice, April 2002 hourly...24-hour average... ± 1 cm hourly...7 24-hours ø [150 weeks] North16.01.00.9 East45.04.60.8 Up52.05.12.5 ZIMM repeatability in [mm] Coordinate validation in NRT Conclusions Positioning GPS meteo Geodynamics AGNES net

27. E. Brockmann EGS Nice, April 2002 Next steps Establishing hourly processing as an operational service (within COST 716) Routine validation (comparison of Swiss LM from weather prediction with GPS) More assimilation tests Quality check of “real” real-time estimates (ZTD estimates from RTK positioning) every 10 minutes Conclusions Positioning GPS meteo Geodynamics AGNES net

28. E. Brockmann EGS Nice, April 2002 Positioning Swiss Positioning Service (swipos®) –swipos - NAV (1-5 meters) >GPS reference station in Zurich (SRG) >DGPS correction data (RTCM, Type 1,2 over FM/RDS or GSM) –swipos - GIS/GEO (cm accuracy) >RTK service over GSM (0900 - Business Number) >Nationwide cm accuracy! Conclusions Positioning GPS meteo Geodynamics AGNES net

29. E. Brockmann EGS Nice, April 2002 Positioning (2) swipos-GIS/GEO is based on the concept of the Virtual Reference Stations (VRS) The approximate position of the user is sent to the central communication computer over GSM Data Approx. position Data Communication Server / VRS Software Field Firewall VRS observations (RTCM 18,19) Data AGNES sites Conclusions Positioning GPS meteo Geodynamics AGNES net

30. E. Brockmann EGS Nice, April 2002 Positioning: Performance tests 14 hours test on “swisstopo” roof 4 hours RAW / VRS performance test (using antenna splitter) Test in different areas and distances and height differences to the AGNES network 2 diploma theses Praxis tests: determination of 73 second order points using RTK and “classical” static GPS Conclusions Positioning GPS meteo Geodynamics AGNES net

31. E. Brockmann EGS Nice, April 2002 Positioning: Performance Test over 14 hours on the swisstopo roof using a Trimble 5700 receiver (with GSM) Registration of the RTK position every second; new initialization every 15 minutes Horizontal rms: ±1.0 cm (1 σ) Vertical rms: ±1.8 cm (1 σ) Conclusions Positioning GPS meteo Geodynamics AGNES net 2 cm

32. E. Brockmann EGS Nice, April 2002 Positioning: Performance (2) Test over 4 hours on the swisstopo roof using 2 Trimble 5700 receiver (with 2 GSM) and 1 Zephyr antenna (+ antenna splitter) Registration of the RTK position every second; new initialization every 15 minutes Horizontal rms: ± 0.7 / ± 0.8 cm (1 σ) Virtuel: 5% float Raw: 45% float Vertical rms: ± 3.6 / ± 2.5 cm (1 σ) Conclusions Positioning GPS meteo Geodynamics AGNES net 2 cm

33. E. Brockmann EGS Nice, April 2002 Positioning: Performance summary 100 seconds to initialization (20 sec. GSM, 80 sec. init.) Horizontally 2-3 cm rms, vertically 3-4 cm rms VRS results do not show a smaller bias compared to RAW data of the nearest AGNES site, but the ambiguity resolution and time to initialization is improved (“factor of 2”) 5 satellite constellations for VRS critical (switch to RAW) Conclusions Positioning GPS meteo Geodynamics AGNES net

34. E. Brockmann EGS Nice, April 2002 Conclusions The Automated GPS Network Switzerland (AGNES) consists of 29 permanent GPS tracking stations AGNES is a multipurpose network: –Reference network for the first order surveys in Switzerland –Analysis of time series of coordinates for geodynamics –1-hour data processing (near real-time) for meteorological applications (numerical weather prediction) –swipos-GIS/GEO: RTK positioning service with nationwide cm accuracy Conclusions Positioning GPS meteo Geodynamics AGNES net