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SC – VRS Network. To Support Surveying and Machine Control. Presentation Overview. Introduction VRS Network Design Antenna Mounting Designs Server Network Design Modeling Network Testing Network Integrity Practical Applications. South Carolina Geodetic Survey. Marine Transportation. - PowerPoint PPT Presentation
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SC – VRS Network
To Support Surveying and Machine Control
Presentation Overview
• Introduction• VRS Network Design• Antenna Mounting Designs• Server Network Design• Modeling• Network Testing• Network Integrity• Practical Applications
South Carolina Geodetic Survey
Marine Transportation
HighwayConstruction
Obstruction Charting
Utilities
SurveyingEngineering
Mapping
Infrastructure
Motivating Force for a Network Application
Antenna Hardware
Stainless Steel MountFor Masonry Buildings
Self Supporting 24 Foot Tower
Tamper-Proof Leveling Head
Server Network Design
Should IT Be a Shareholder?
5
6
7
Modeling
???
I(λ,φ) = I0 +aλ∆λ + aφ∆φ 1 cm
-1 cm
2 – 12hr Multipath PlotsAreal Variant Ionospheric Model
The solution of Integer Ambiguityis influenced by external variables
Atmosphere - Tropo, IonClock Error - SV and ReceiverSV Orbit ErrorMultipathSeparation of Base and Rover
SC - VRS Network Design
VRS Is Not Built In a Day!There Are Many Stakeholders!!
They Are ALL Critical To Your Success
Test Network
11 Counties, 6700 Sq Mi, 10 VRS Base Stations, 50 Control Pts
VRS Absolute Accuracy
Comparison of VRS and NGS Height Mod ControlAbsolute 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*
Time (sec) 300 60 5
Horizontal (cm) 1.98 2.40 2.41
Vertical (cm) 2.25 2.39 2.40
*(Local Accuracy2 + Eccentricty2 + System Design2)1/2
Station SCBY
Vertical Axis -0.010 to 0.014m
Poor Choice for a Base Station!
Vertical Axis -0.04 to 0.055m
Diurnal E-W Motion of a 90 Foot Spun Concrete Tower
-3.0 -2.0 -1.0 0.0 1.0 2.0 3.0Centimeters
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
Practical Applications
Tidal Datum Transfer
2 mile transfer0.05 ft uncertainty
VRS Elevation (ft) Leveling (ft) Difference4.557 4.560 0.0034.488 4.482 -0.0074.423 4.436 0.0134.656 4.649 -0.007
4.327 4.337 0.0104.528 4.528 0.0004.810 4.800 -0.0104.941 4.948 0.007
Mean/SDV 0.001/0.008
Classical Leveling vs VRS
1st Order Class 2 Leveling4 Surveyors4 days5.5km – 6mm
1 Surveyor4 hours12mm comparison
VRS Elevation (ft) Leveling (ft) Difference4.557 4.560 0.0034.488 4.482 -0.0074.423 4.436 0.0134.656 4.649 -0.007
4.314 4.265 -0.0494.327 4.337 0.0104.528 4.528 0.0004.810 4.800 -0.0104.941 4.948 0.0074.964 5.020 0.056
Mean/SDV 0.002/0.025
Comparison of VRS to Total StationRelative Accuracy
Grid Brg Angle Rt Grd Dist
TPT1 SURVEY 068/00/55TPT1 TPT2 207/30/58 220/29/57 544.669 VRS
220/29/55.2 544.678 Total Station139/30/03 Interior Angle
TPT2 TPT1 027/30/58TPT2 TPT3 198/49/59 188/40/59 957.778 VRS
188/40/57.2 957.769 Total Station171/19/01 Interior Angle
TPT3 TPT2 018/49/59TPT3 SURVEY 038/08/33 340/41/26 2165.470 VRS
340/41/27.5 2165.441 Total Station019/18/34 Interior Angle
SURVEY TPT1 248/00/55 837.523 VRS837.500 Total Station
SURVEY TPT3 218/08/33 029/52/22 Interior Angle029/52/21.0
360/00/00 VRS359/59/59.1 Total Station
Ellipsoid Height Distortions of 3CM or Greater
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 -0.015 0.002-0.020 -0.017 -0.003-0.024 -0.015 -0.009-0.041 -0.015 -0.026-0.007 -0.008 0.001-0.011 -0.012 0.001-0.018 -0.012 -0.006-0.021 -0.018 -0.003-0.003 -0.012 0.009-0.048 -0.020 -0.028-0.044 -0.019 -0.025-0.028 -0.018 -0.010-0.024 -0.026 0.002-0.026 -0.025 -0.001-0.027 -0.024 -0.003-0.037 -0.023 -0.014-0.035 -0.024 -0.011-0.017 -0.023 0.006-0.022 -0.021 -0.001-0.049 -0.026 -0.023
-0.025 -0.019 -0.007-0.012 0.005 0.010
2 – 10 Minute Sessions Separated by 27 Hours
MeanStd Dev
Pub-Obs Pub-Pred Obs-Pred
Predicted values are weighted* means of the Network-OPUS Differences
*Weight Equals Ratio of Base StationSeparation Multiplied by Assumed Error
Network Integrity
24-Hour Coordinate Spread 1 cm N & E1.5 cm Ellipsoid Ht
Semi-Major Axis ~ 1 cm
Concluding Remarks
• Number of Registered Users• Maintenance Plan• Replacement Plan• Integrity Monitoring• Cost• Subscription Fee• Questions?