Using GPS with Real Time Correction

Presenter Warren EadeField Services Manager

System Requirements

• GPS system capable of receiving external corrections– Built-in– External

• An external correction source – Satellite– Radio– cellular

Correction Sources

• Virtual Reference Station (VRS)• OmniSTAR• SBAS & WaaS• Single Base • Marine Beacon

Pacific Region

• OmniSTAR– Land service– Marine Service

• Marine Beacon– Marine Service that can work for Land

OmniStar

• A subscription satellite broadcast Service• 3 Service levels (VBS, XP 20-30cm, HP 10cm)

• (Not all available in some areas)

• 2 Wet Services• Subscription available for– Day– Week– Month– Year

Coverage

Requirements of the GPS

• GPS needs to have OmniSTAR Receiver built in– Eg Trimble ProXRT, Ag332, SPS-750, SPS-850• Also supported in some Ashtech & Topcon

• External receivers from OmniStar

How it works1. GPS satellites 2. Multiple OmniSTAR GPS Reference Sites 3. Send GPS corrections via lease line to 4. Houston Network Control Center where data corrections are checked and repackaged for

uplink to 5. L- Band Geostationary Satellite 6. Typical Geostationary L-Band satellite footprint. 7. Correction data are received and applied real-time

Setup Inside TerraSync

Limitation

• GPS Needs OmniSTAR receiver• Subscription service• Due to the course vector base map used by

OmniSTAR, Marine wet service is needed in the Island.

• May need up to 15 deg horizon plane to see broadcast Satelite

Who Might Use This?

• Water and waste water services• Teleco’s• Electricity authorities• Irrigation projects• Stake outs• Emergency relief projects• Prelim site survey’s• Agriculture

Questions?

References• www.omnistar.com.au• www.trimble.com

warren.eade@geosystems.co.nz