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AUSTRALIAN LOCAL TIE SURVEYS

AUSTRALIAN LOCAL TIE SURVEYS. PLAN OF PRESENTATION. Stromlo Network Design Monument Design Calibration Targets Instrumentation and Methodology Survey-to-Survey Consistency GPS Stability Survey Report Format MINICO and Calibration Stability See also the BIG ORANGE POSTER.

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AUSTRALIAN LOCAL TIE SURVEYS

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  1. AUSTRALIAN LOCAL TIE SURVEYS

  2. PLAN OF PRESENTATION • Stromlo Network Design • Monument Design • Calibration Targets • Instrumentation and Methodology • Survey-to-Survey Consistency • GPS Stability • Survey Report Format • MINICO and Calibration Stability See also the BIG ORANGE POSTER

  3. STROMLO LOCAL TIES

  4. SLR, DIMM, NEW MONUMENT & NORTH PIER

  5. FIDUCIAL MONUMENT & MASSIVE BASE

  6. FIDUCIAL & GLONASS CONE

  7. SURVEY PLATE ATOP FIDUCIAL

  8. NEW GPS MONUMENT & MASSIVE BASS

  9. TOP OF NEW MONUMENT

  10. GA MONUMENT DESIGN

  11. GA MONUMENT – TOP DETAIL

  12. NORTH PIER WITH GPS & CAL TARGET

  13. SITES SURVEYED BY GA EVERY TWO YEARS (where possible) • Yarragadee (SLR/GPS/DORIS/GLONASS/Absolute-Gravity); • Mount Stromlo (SLR/GPS/ DORIS/GLONASS); • Orroral (SLR now obsolete, was 27km from Tidbinbilla); • Hobart (VLBI/GPS/Absolute-Gravity); • Tidbinbilla. (VLBI/GPS); • Darwin (GPS/GLONASS); • Davis, Antarctica (GPS/GLONASS/Tide-Gauge). ALSO: GPS to tide gauge connections throughout the South Pacific including stations at Samoa, Cook Islands, Fiji, Tuvalu, Tonga, Manus Island, PNG, Kiribati, Vanuatu, Nauru and Micronesia

  14. PLANNING AND STRATEGIES • Be timed for optimum survey observations, i.e. timing the survey when weather conditions are neutral to minimise atmospheric effects; • Allow for several days down time, particularly on Satellite Laser Ranging (SLR) or Very Long Baseline Interferometry (VLBI) systems; • Be planned to avoid critical tracking campaigns; • Plan the placement of marks on the telescope/antenna to optimise observations for the determination of axes (in the case of indirect reference point determination), i.e. optimise the target trajectories and the radius of the trajectories; and • Place instrument stand-points to satisfy survey accuracy demands (as determined by network simulation if necessary). • Forced centring is used to eliminate the introduction of setup errors wherever possible. A Leica Zenith Nadir precise optical plummet is used for all tripod setups, to ensure near zero plumbing errors. Additionally, wherever possible concrete pillars are used for instrument standpoints. This ensures setup stability during the often long observation periods when observations are taken to the antenna or telescope systems.

  15. EQUIPMENT & CALIBRATION • Leica TCA 2003 Total Station • Angular Precision (lab. calibrated) 0.”6 • Distance Precision (lab.calibrated) 0.5mm + 0.4ppm • Annually compared with standard baseline traceable to Aust’n National Standards • Leica precision prisms with tribrach and carriers incl. plate bubble • Annually calibrated over standard baseline, plus GPS • Zenith nadir plummet for centring tripods • Fixed height prism pole for Total Station levelling • Invar staff for instrument heighting, calibrated biennially.

  16. GPS DORIS ARP MONUMENTATION AND NETWORK DESIGN • Ideally instrument standpoints are stable bedrock anchored pillars; • Pillars should have reference marks to monitor local deformation; and • Survey marks should have anunambiguous reference point.

  17. INVARIANT POINT DETERMINATION

  18. RMS of IVP RESIDIALS:PRIMARY (Az or X) AXIS

  19. RMS OF IVP RESIDUALSSECONDARY (EL or Y) AXIS

  20. RMS MINIMUM DISTANCE BETWEEN AXES

  21. REPEATABILITY, SURVEY-TO-SURVEY

  22. 3 YEARS OF GPS DIFFERENCES, NORTH PIER TO FIDUCIAL MONUMENTY grid spacing is 1 mm

  23. THE AUSTRALIAN SURVEY REPORT FORMAT • Survey database • To ensure the long term archiving and storage of the survey results all report information is stored in the National Geodetic DataBase (NGDB), which is a Windows relational database of geodetic positions and associated information. All survey are stored with the following information: • Earth-centred Cartesian coordinates • Latitude, Longitude & ellipsoidal height automatically computed • Reference frame & epoch • Referenced to source of positions (SINEX file) • Exact mark descriptions • Images & diagrams • The NGDB allows the automatic generation of technical reports that are fully user definable. Survey marks at each observatory are linked to facilitate easy report extraction. • Report distribution • All Geoscience Australia survey reports are deposited on the Geoscience Australia web site located at www.ga.gov.au. SINEX format results files are deposited on the Geoscience Australia ftp server, located at ftp.ga.gov.au/sgac/sinex/ties.

  24. STROMLO ~ weekly 4-GROUND TARGET ‘MINICO’ STABILITY, Jan-Jun 2005

  25. CALIBRATION VALUES, May – July 2005From NICT Daily Reports

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