High Accuracy GPS Mapping and VRS

1. High Accuracy GPS Mapping and VRS Lanny Schnipper Seiler Instrument 2008 IGIC Conference Indianapolis, IN

2. VRS in Action • No base setup • get to the job • dial in • Check • start working • MWRTK VRS in Indiana • save time • save money

3. Overview • Review GPS • Discuss use of Virtual Reference Stations (VRS) • Obtaining highly accurate GIS/GPS positions • Continuously Operating Reference Stations (CORS) • Real-Time differential results

4. What is VRS? • GPSNet, DGPSNet, RTKNet • Links a network of reference stations • Provides quality control of incoming data • Logs files for post-processing • Network modeling of systematic errors • Real time broadcast of true network DGPS and RTK solutions

5. VRSData Flow Reference stations data streams back to the server through LAN, Internet, or radio links

6. VRSData Flow User’s receiver sends an NMEA string back to server using cellular modem. Virtual Reference Station position is established. VRS NMEA—GGA

7. VRSData Flow Server uses VRS position to create corrected observables and broadcasts them to the user end. RTCM or CMR+ VRS

8. Why use VRS? • Eliminates the need for Users to establish DGPS base/reference station(s) • More reference stations = shorter vectors/ baselines • Shorter baselines = less atmospheric errors • Network atmospheric modeling • Extended operating range with improved accuracy

9. Why use VRS? • VRS provides integrity monitoring • All users in common, established coordinate frame • Eliminates the dependency on single base/reference station • Graceful degradation should a reference station fail • Uses established communications

10. Indiana MWRTK 26 Stations …and growing!

11. Indiana MWRTK www.mwrtk.net

12. Real Time in TerraSync/ArcPad • External correction source • Data radio • Beacon-on-a-Belt (BoB™) receiver • GeoBeacon • SBAS (WAAS) • TerraSync Version 2.30 (2/03) added VRS • Network VRS • Single base • GPSCorrect Version 1.1 (4/05)

13. SupportVRS corrections • GeoExplorer CE series with GPS firmware version 1.03: • GeoXT • GeoXM • GeoXH • GPS Pathfinder with firmware version 1.52 or later: • GPS Pathfinder Power • GPS Pathfinder Pro XRS • GPS Pathfinder Pro XR • GPS Pathfinder ProXH • GPS Pathfinder ProXT

14. Connecting to VRS • Internet connection to the VRS server • GPRS-capable cellphone • WiFi Hotspot • Serial cable connection • Data radio

15. Outside TerraSync • Start  Settings  Connections • Make connection to your Phone or other device • Test Internet Explorer to insure connection was successful

16. Inside TerraSync • Start TerraSync • Select Setup section • Set Real-time Settings • Choice 1 field select External Source. • Configure the external source • From the Type field, select VRS • or select the Single Base option • Connection Method field, select Internet • Address field, enter the IP address or URL of the VRS server. • IP Address: 64.123.250.18for MWRTK • IP Port: 2101for MWRTK

17. Accuracy • Submeter with a GeoXT/XH • Usually subfoot • We have even seen less than 6 inches! • No post-processing required

18. Subscription • VRS is a paid subscription • Seiler provides Logon and password • MWRTK.NET • Single Day - $20 per day, 3-day minimum per month maximum monthly charge $200(Billed monthly) • Single Month- $150(Billed monthly and payable in advance) • Single Quarter- $375 ($125 per month)(Billed quarterly and payable in advance) • One Year- $1,200(Billed $225.00 per quarter and payable in advance)

19. Questions?