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Geodetic Stuff You Need to Know: Datums, Standards and Strategies LINDA MORGAN PRINCIPAL CONSULTANT – SPATIAL POSITIONING WESTERN AUSTRALIA SURVEYING CONFERENCE 2013 Geodetic Datum Background GDA94 Based on ITRF 1992, Epoch 1 January 1994. AFN - 8 CORS Sites – 2 in WA ANN - 79 Campaign GPS Sites – 20 in WA Statefix - 80 campaign GPS sites in WA Implemented in WA on 4 December 2000. Shift from AGD84 ~ 200m Geodetic Datum Drivers for Change – Tectonic Motion Geodetic Datum Drivers for Change – Localised Deformation Point Heading Type point here Point Heading Type point here Point Heading Type point here Geodetic Datum Drivers for Change – Improved Reference Frame International Terrestrial Reference Frame 1992, 1994, 1996, 1997, 2000, 2005, 2008, ...2013 Geodetic Datum Drivers for Change – An explosion of Global Navigation Satellite Systems Geodetic Datum Drivers for Change – More Uses Precision positioning will contribute 2.1% of Australia’s GDP by 2030 Automated mines, driverless cars, UAVs Geodetic Datum Drivers for Change – More Users Precise coordinates for and by the masses (no monopoly for surveyors anymore) Geodetic Datum How we have grown – more Continuously Operating Reference Stations (CORS) Geodetic Datum A New Geodetic Datum National GNSS CORS Solution Australian Terrestrial Reference Frame (ATRF) National GNSS Campaign Solution Fully rigorous geometric adjustment Jurisdictional Adjustments aspire for an all stationsand-observations adjustment phased-adjustment strategy Geodetic Datum Roadmap for a New Geodetic Datum 2015 GDA2020 1990 2000 2010 2020 0.00m 0.49m 1.12m 1.82m GDA94 Gazetted GDA94 Adopted in WA Shift from GDA94 GDA Dynamic Adoption and User Implementation Geodetic Datum GDA 2020 - What are we aiming for Datum that supports +/- 2 cm user positioning (PU 95% CL) Datum updated continuously as new observations are contributed Fully 3-D datum (i.e. ellipsoidal) Datum supports the continuous update of the national Geoid model Datum supports time-based corrections (i.e. deformation models) Datum has tools and services that facilitate its use by the massmarket (e.g., time based transformations) Relative uncertainty can be computed between any survey marks Geodetic Datum What does it mean for WA Geodetic Datum Next Steps 2015 target date for completion of the National Adjustment Stakeholder consultation through 2013 Datum Workshop WALIS Forum November 2013 Ongoing Development of the National Adjustment Research through the Cooperative Research Centre for Spatial Information on coordinate dynamics and streamlining data exchange and processes. Standards and Practices for Control Surveys (SP1) Brief History First published in 1966 as Standard Specifications and Recommended Practices for Horizontal and Vertical Control Surveys National Mapping Council’s first Technical Document hence the name – Special Publication 1 Extensively revised in 1986 and renamed Standards and Practices for Control Surveys Many revisions from 1990-2007 - current version 1.7 Standards and Practices for Control Surveys (SP1) Current Status of SP1 Version 2 The current review commenced in 2009. Major structural change Shift from Class and Order to Coordinate Uncertainty Less prescription for survey practice guidelines Outcomes based First public draft released for feedback in mid 2012. Draft version now being revised based on feedback. Release date 30 June 2013. Standards and Practices for Control Surveys (SP1) Structure of SP1 Version 2 Standards and Practices for Control Surveys (SP1) Purpose and Scope of SP1 Version 2 Specify minimum requirements - For the determination of 1D, 2D or 3D position and uncertainty of Australia’s survey control marks Promote the adoption of uniform procedures - To achieve the highest level of rigor and integrity in the establishment and maintenance of Australia’s survey control mark network Scope – surveys that define, improve, extend or connect to the network - Datum control surveys - General purpose control surveys Standards and Practices for Control Surveys (SP1) The Standard Quantifying Survey Quality - Survey Uncertainty – based on a minimally constrained adjustment, to evaluate the survey quality independent of the datum - Positional Uncertainty – based on the constrained adjustment, to evaluate the survey quality with respect to the datum - Relative Uncertainty – the uncertainty between survey mark coordinates derived from SU or PU. Standards and Practices for Control Surveys (SP1) The Standard Expressing Survey Uncertainty – shall be in terms of the 95% confidence level as either - Standard Deviations - Error Ellipses or - Error Circles AHD – PU currently unavailable, can only use SU or RU Standards and Practices for Control Surveys (SP1) Next Steps Release date 30 June 2013 Implementation phase Annual reviews Geodetic Strategy New Strategy for 2013-2018 Customer survey Draft prepared Industry review Landgate signoff Datums, Standards and Strategies Summary A new Geodetic Datum is in the making WALIS Forum Datum Workshop Nov 2013 SP1 Version 2 to be released 30 June 2013 Class and Order is out Coordinate Uncertainty the new quality indicator Outcomes based, not process driven Geodetic Strategy under review and revision Customer Survey - please participate Questions? [email protected]