Presented by:Leila Hernandez

Dennis Manglicmot

GMAT 9205 Fundamentals of Geo-positioning

Continuously Operating Reference System (CORS)Permanent base stations that are used

to continuously observe and measure using Global Navigation Satellite System (GNSS)

provide real time accurate positioningIncorporated into networks to reduce errors

and to have a capability to deliver positioning services for a state, a country or world-wide

Used as part of the realization of the State Datums

AgricultureMiningConstructionScientificSurveyingNavigationMapping

CORS Application

Some of the CORS Networks in Australia AFNARGNGPSnetwork PerthSouth Australia CORS networkSmartNet AusSunPOZVICmap POS GPSNet™CORSnet NSW

CORS: AustraliaAustralian Fiducial Network (AFN)

comprises of 8 stations within mainland Australia (including Tasmania)

Connects to ITRF

Australian Regional GPS Network (ARGN) – combination of the AFN and 8 other stations beyond the mainland Australia

GPSnetwork PerthUses Virtual Reference

Stations (VRS) to eliminate potential systematic errors

World’s first privately owned and operated VRS network which supports GNSS capabilities

South Australian CORS NetworkMetro Network – 8

operating stations with 2cm accuracy using NRTK within 80km of Adelaide CBD

SA Statewide Network

SmartNet AusUtilises Leica Geosystems’ Spider software to

create RTK corrections in various formatsAvailable in South Australia and in Gold

Coast, QLD

SunPOZ

Covers south-east corner of Queensland

Uses Trimble’s VRS™ technology

VicMap Position - GPSnet™• Private and

public stakeholders

• More than 100 stations

• Accuracy: ±2cm within 25km of CORS

Number of stations

May

2011: 61 Future:

120

Data Services DGPS RTK RINEX

CORSnet-NSW

Additional InformationVicMap POS GPSNet™ is currently the

largest CORS network in Australia

In Perth and South Australia, reference stations are managed by private companies

Data accessibility can sometimes be an issue

CORS and Reference Datum WGS84 • recalculated every few years for GPS control

GDA94 • based on ITRF92 but is fixed on a number of reference points in Australia• compatible with modern positioning techniques e.g. GPS

ConcernsSurveyors and spatial professionals

represents only a small minority of future CORS users in Australia.

ITRF is realised every 3 or so years and Australian Datum is realised every 30 years or so

Plate tectonic movement of 7cm per year NNE direction

Concerns (cont’d)The need to have modern GNSS positioning

techniques and surveying techniques and to ensure they are accurate, reliable and easy to use

Interoperability with other state’s CORS networks

Compatibility of AUSPOS

Legal Traceability

Significant distortions in the GDA94 (1997) for NSW

Solution: GDA94 (2010)Defined to improve shortcomings of the initial

datum definition and reduce distortion3-dimensional coordinate systemProvides direct connection to the Australian

Fiducial Network (AFN) and Australian Regional GNSS Network (ARGN)Potential sources of error eliminatedDistortion-free spatial control across the networkImproved positioning framework

Regulation 13 certificates

Global GDA implementationCORS networks using ‘global’ GDA

VicMap POS GPSnet™SmartNet Aus

CORSnet NSWSunPOZ

A few things to note:

Complete re-adjustment of geodetic ground control networks in NSW will be done after GDA2015 is implemented.

Site calibration will continue to be essential GNSS survey practice in NSW to relate the two realisations of GDA94 to each other.

However, site calibration is essential only for applications that needs to be tied to existing ground control network

References:GPS Network Perth 2011, GPS Network Perth , viewed

29 May 2011, <http://www.gpsnetworkperth.com.au>.Haasdyk, J 2009, “Automatic Bernese Processing of

CORSnet-NSW GPS data for deformation monitoring” , Engineering thesis, University of New South Wales

Janssen, V & McElroy, S 2011, “Coordinates and CORSnet-NSW: Dealing with distortions in GDA94”, Position, no. 50, pp. 24-27.

Janssen, V and White, A and Yan, T (2010) CORSnet-NSW: Towards state-wide CORS infrastructure for New South Wales, Australia. In: Proceedings of XXIV FIG International Congress, 11-16 April 2010, Sydney, Australia.

References (cont’d):NSW Land and Property Management Authority c 2011,

CORSnet-NSW, LPMA, booklet.Roberts, C 2009, “CORS GNSS networks: A Superior

Infrastructure for Precision Agriculture”, Southern Precision Agriculture Association Conference, Adelaide, 4 September 2009.

South Australian CORS Network, viewed 29 May 2011, <http://www.cors.com.au/technical-info/cors-network>.

Victoria Department of Sustainability and Environment, Vicmap Position – GPS net, DSE, booklet.

VicMap Position - GPSnet 2011 , VicMap Position – GPSnet, viewed 29 May 2011 <http://gnss.vicpos.com.au>.