SC – VRS Network

1. SC – VRS Network To Support Surveying and Machine Control

2. Presentation Overview • Introduction • VRS Network Design • Antenna Mounting Designs • Server Network Design • Modeling • Network Testing • Network Integrity • Practical Applications

3. South Carolina Geodetic Survey Marine Transportation Highway Construction Infrastructure Mapping Obstruction Charting Surveying Engineering Utilities

4. Motivating Force for a Network Application

5. Antenna Hardware Tamper-Proof Leveling Head Stainless Steel Mount For Masonry Buildings Self Supporting 24 Foot Tower

6. Server Network Design Should IT Be a Shareholder? 5 6 7

7. Modeling Atmosphere - Tropo, Ion Clock Error - SV and Receiver SV Orbit Error Multipath Separation of Base and Rover The solution of Integer Ambiguity is influenced by external variables ??? Areal Variant Ionospheric Model 2 – 12hr Multipath Plots 1 cm I(λ,φ) = I0 +aλ∆λ + aφ∆φ -1 cm

8. SC - VRS Network Design VRS Is Not Built In a Day! There Are Many Stakeholders!! They Are ALL Critical To Your Success

9. Test Network 11 Counties, 6700 Sq Mi, 10 VRS Base Stations, 50 Control Pts

10. VRS Absolute Accuracy Comparison of VRS and NGS Height Mod Control Absolute Accuracy Meters Allowable 2-D RMSEr 95% = 1.7308 * RMSEr = (2.0*2.0 + 0.3*0.3 + 1.2*1.2)1/2 = 2.4 cm* Allowable 1-D RMSEv 95% = 1.9600*RMSEv = (2.0*2.0 + 0.3*0.3 + 2.4*2.4)1/2 = 3.1 cm* *(Local Accuracy2 + Eccentricty2 + System Design2)1/2

11. Station SCBY Vertical Axis -0.010 to 0.014m

12. Poor Choice for a Base Station! Vertical Axis -0.04 to 0.055m Diurnal E-W Motion of a 90 Foot Spun Concrete Tower

13. Results From Test Of The SC RTN to Determine Accurate Ellipsoid Heights 95% Less Than 2.5 CM From Published Value -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 Centimeters Each Depicted Value Is A Mean Of Two 5-Minute Observations Spaced Approximately 21 or 27 Hours Apart

14. Practical Applications

15. Tidal Datum Transfer 2 mile transfer 0.05 ft uncertainty

16. Classical Leveling vs VRS 1st Order Class 2 Leveling 4 Surveyors 4 days 5.5km – 6mm 1 Surveyor 4 hours 12mm comparison

17. Comparison of VRS to Total StationRelative Accuracy Grid Brg Angle Rt Grd Dist TPT1 SURVEY 068/00/55 TPT1 TPT2 207/30/58 220/29/57 544.669 VRS 220/29/55.2 544.678 Total Station 139/30/03 Interior Angle TPT2 TPT1 027/30/58 TPT2 TPT3 198/49/59 188/40/59 957.778 VRS 188/40/57.2 957.769 Total Station 171/19/01 Interior Angle TPT3 TPT2 018/49/59 TPT3 SURVEY 038/08/33 340/41/26 2165.470 VRS 340/41/27.5 2165.441 Total Station 019/18/34 Interior Angle SURVEY TPT1 248/00/55 837.523 VRS 837.500 Total Station SURVEY TPT3 218/08/33 029/52/22 Interior Angle 029/52/21.0 360/00/00 VRS 359/59/59.1 Total Station

18. Ellipsoid Height Distortions of 3CM or Greater

19. Network vs OPUS Pub-Obs Pub-Pred Obs-Pred 2 – 10 Minute Sessions Separated by 27 Hours Predicted values are weighted* means of the Network-OPUS Differences *Weight Equals Ratio of Base Station Separation Multiplied by Assumed Error Mean Std Dev

20. Network Integrity Semi-Major Axis ~ 1 cm 24-Hour Coordinate Spread 1 cm N & E 1.5 cm Ellipsoid Ht

21. Concluding Remarks • Number of Registered Users • Maintenance Plan • Replacement Plan • Integrity Monitoring • Cost • Subscription Fee • Questions?