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 Obstruction Charting Utilities Surveying Engineering Mapping Infrastructure

4. Motivating Force for a Network Application

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

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

7. Modeling ??? I(λ,φ) = I 0 +a λ ∆λ + a φ ∆φ 1 cm -1 cm 2 – 12hr Multipath Plots Areal Variant Ionospheric Model The solution of Integer Ambiguity is influenced by external variables Atmosphere - Tropo, Ion Clock Error - SV and Receiver SV Orbit Error Multipath Separation of Base and Rover

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 RMSE r 95% = 1.7308 * RMSE r = (2.0*2.0 + 0.3*0.3 + 1.2*1.2) 1/2 = 2.4 cm* Allowable 1-D RMSE v 95% = 1.9600*RMSE v = (2.0*2.0 + 0.3*0.3 + 2.4*2.4) 1/2 = 3.1 cm* Time (sec)300605 Horizontal (cm)1.982.402.41 Vertical (cm)2.252.392.40 *(Local Accuracy 2 + Eccentricty 2 + System Design 2 ) 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. -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 95% Less Than 2.5 CM From Published Value Results From Test Of The SC RTN to Determine Accurate Ellipsoid Heights

14. Practical Applications

15. Tidal Datum Transfer 2 mile transfer 0.05 ft uncertainty VRS Elevation (ft)Leveling (ft)Difference 4.5574.5600.003 4.4884.482-0.007 4.4234.4360.013 4.6564.649-0.007 4.3274.3370.010 4.528 0.000 4.8104.800-0.010 4.9414.9480.007 Mean/SDV0.001/0.008

16. Classical Leveling vs VRS 1 st Order Class 2 Leveling 4 Surveyors 4 days 5.5km – 6mm 1 Surveyor 4 hours 12mm comparison VRS Elevation (ft)Leveling (ft)Difference 4.5574.5600.003 4.4884.482-0.007 4.4234.4360.013 4.6564.649-0.007 4.3144.265-0.049 4.3274.3370.010 4.528 0.000 4.8104.800-0.010 4.9414.9480.007 4.9645.0200.056 Mean/SDV0.002/0.025

17. Comparison of VRS to Total Station Relative Accuracy Grid BrgAngle RtGrd Dist TPT1SURVEY068/00/55 TPT1TPT2207/30/58220/29/57544.669VRS 220/29/55.2 544.678Total Station 139/30/03Interior Angle TPT2TPT1027/30/58 TPT2TPT3198/49/59188/40/59957.778VRS 188/40/57.2957.769 Total Station 171/19/01Interior Angle TPT3TPT2018/49/59 TPT3SURVEY038/08/33340/41/262165.470VRS 340/41/27.52165.441 Total Station 019/18/34Interior Angle SURVEYTPT1248/00/55837.523VRS 837.500 Total Station SURVEYTPT3218/08/33029/52/22Interior Angle 029/52/21.0 360/00/00VRS 359/59/59.1Total Station

18. Ellipsoid Height Distortions of 3CM or Greater

19. Network vs OPUS -0.020-0.016-0.004 -0.032-0.021-0.011 -0.015-0.012-0.003 -0.022-0.020-0.002 -0.013-0.0150.002 -0.020-0.017-0.003 -0.024-0.015-0.009 -0.041-0.015-0.026 -0.007-0.0080.001 -0.011-0.0120.001 -0.018-0.012-0.006 -0.021-0.018-0.003 -0.0120.009 -0.048-0.020-0.028 -0.044-0.019-0.025 -0.028-0.018-0.010 -0.024-0.0260.002 -0.026-0.025-0.001 -0.027-0.024-0.003 -0.037-0.023-0.014 -0.035-0.024-0.011 -0.017-0.0230.006 -0.022-0.021-0.001 -0.049-0.026-0.023 -0.025-0.019-0.007 -0.0120.0050.010 2 – 10 Minute Sessions Separated by 27 Hours Mean Std Dev Pub-ObsPub-PredObs-Pred Predicted values are weighted* means of the Network-OPUS Differences *Weight Equals Ratio of Base Station Separation Multiplied by Assumed Error

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

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