linda morgan principal consultant – spatial positioning western australia surveying conference...
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LINDA MORGAN PRINCIPAL CONSULTANT – SPATIAL POSITIONINGWESTERN AUSTRALIA SURVEYING CONFERENCE 2013
Geodetic Stuff You Need to Know:Datums, Standards and Strategies
Background
Geodetic Datum
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
Drivers for Change – Tectonic Motion
Geodetic Datum
Drivers for Change – Localised Deformation
Geodetic Datum
Point HeadingType point here
Point HeadingType point here
Point HeadingType point here
Drivers for Change – Improved Reference Frame
Geodetic Datum
International Terrestrial Reference Frame1992, 1994, 1996, 1997, 2000, 2005, 2008, ...2013
Drivers for Change – An explosion of Global Navigation Satellite Systems
Geodetic Datum
Drivers for Change – More Uses
Geodetic Datum
Automated mines,driverless cars,
UAVs
Precision positioning will contribute 2.1% of Australia’s
GDP by 2030
Drivers for Change – More Users
Geodetic Datum
Precise coordinates for and by the
masses (no monopoly for
surveyors anymore)
How we have grown – more Continuously Operating Reference Stations (CORS)
Geodetic Datum
A New Geodetic Datum
Geodetic Datum
National GNSS CORS Solution
Australian TerrestrialReference Frame (ATRF)
National GNSS Campaign Solution
Jurisdictional Adjustments
Fully rigorous geometric adjustment
aspire for an all stations-and-observations adjustment phased-adjustment strategy
Roadmap for a New Geodetic Datum
Geodetic Datum
1990 2000 2010 2020
GDA94Adopted in WA
GDADynamic
2015GDA2020
Adoption and User Implementation
GDA94Gazetted
0.00m 0.49m 1.12m 1.82m Shift from GDA94
GDA 2020 - What are we aiming for
Geodetic Datum
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 mass-
market (e.g., time based transformations) Relative uncertainty can be computed between any survey marks
What does it mean for WA
Geodetic Datum
Next Steps
Geodetic Datum
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.
Brief History
Standards and Practices for Control Surveys (SP1)
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
Current Status of SP1 Version 2
Standards and Practices for Control Surveys (SP1)
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.
Structure of SP1 Version 2
Standards and Practices for Control Surveys (SP1)
Purpose and Scope of SP1 Version 2
Standards and Practices for Control Surveys (SP1)
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
The Standard
Standards and Practices for Control Surveys (SP1)
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.
The Standard
Standards and Practices for Control Surveys (SP1)
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
Next Steps
Standards and Practices for Control Surveys (SP1)
Release date 30 June 2013 Implementation phase Annual reviews
New Strategy for 2013-2018
Geodetic Strategy
Customer survey Draft prepared Industry review Landgate signoff
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
Datums, Standards and StrategiesSummary