SC VRS Network To Support Surveying and Machine

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 Highway Construction Infrastructure Mapping Obstruction Charting Surveying Engineering Utilities

Motivating Force for a Network Application

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

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

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

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 Control Absolute Accuracy Meters Time (sec) 300 60 5 Horizontal (cm) 1. 98 2. 40 2. 41 Vertical (cm) 2. 25 2. 39 2. 40 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 Accuracy 2 + Eccentricty 2 + System Design 2)1/2

Station SCBY Vertical Axis -0. 010 to 0. 014 m

Poor Choice for a Base Station! Vertical Axis -0. 04 to 0. 055 m Diurnal E-W Motion of a 90 Foot Spun Concrete Tower

Results From Test Of The SC RTN to Determine Accurate Ellipsoid Heights 95% Less Than 2. 5 CM From Published Value 35 30 Differences from Published Ellipsoid Heights 25 20 15 10 5 0 -3. 0 -2. 0 -1. 0 0. 0 1. 0 Centimeters 2. 0 3. 0 Each Depicted Value Is A Mean Of Two 5 -Minute Observations Spaced Approximately 21 or 27 Hours Apart

Practical Applications

Tidal Datum Transfer VRS Elevation (ft) 4. 557 4. 488 4. 423 4. 656 4. 327 4. 528 4. 810 4. 941 Mean/SDV Leveling (ft) Difference 4. 560 0. 003 4. 482 -0. 007 4. 436 0. 013 4. 649 -0. 007 4. 337 4. 528 4. 800 4. 948 0. 010 0. 000 -0. 010 0. 007 0. 001/0. 008 2 mile transfer 0. 05 ft uncertainty

Classical Leveling vs VRS 1 st Order Class 2 Leveling 4 Surveyors 4 days 5. 5 km – 6 mm VRS Elevation (ft) 4. 557 4. 488 4. 423 4. 656 4. 314 4. 327 4. 528 4. 810 4. 941 4. 964 Mean/SDV Leveling (ft) Difference 4. 560 0. 003 4. 482 -0. 007 4. 436 0. 013 4. 649 -0. 007 4. 265 4. 337 4. 528 4. 800 4. 948 5. 020 -0. 049 0. 010 0. 000 -0. 010 0. 007 0. 056 0. 002/0. 025 1 Surveyor 4 hours 12 mm comparison

Comparison of VRS to Total Station Relative Accuracy Grid Brg TPT 1 SURVEY TPT 2 068/00/55 207/30/58 TPT 2 TPT 1 TPT 3 027/30/58 198/49/59 TPT 3 TPT 2 SURVEY 018/49/59 038/08/33 SURVEY TPT 1 248/00/55 SURVEY TPT 3 218/08/33 Angle Rt Grd Dist 220/29/57 220/29/55. 2 139/30/03 544. 669 544. 678 VRS Total Station Interior Angle 188/40/59 188/40/57. 2 171/19/01 957. 778 957. 769 VRS Total Station Interior Angle 340/41/26 340/41/27. 5 019/18/34 2165. 470 VRS 2165. 441 Total Station Interior Angle 837. 523 837. 500 029/52/22 029/52/21. 0 360/00/00 359/59/59. 1 VRS Total Station Interior Angle VRS Total Station

Ellipsoid Height Distortions of 3 CM or Greater

Network vs OPUS Pub-Obs 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 Pub-Pred Obs-Pred -0. 020 -0. 032 -0. 015 -0. 022 -0. 013 -0. 020 -0. 024 -0. 041 -0. 007 -0. 011 -0. 018 -0. 021 -0. 003 -0. 048 -0. 044 -0. 028 -0. 024 -0. 026 -0. 027 -0. 035 -0. 017 -0. 022 -0. 049 -0. 016 -0. 021 -0. 012 -0. 020 -0. 015 -0. 017 -0. 015 -0. 008 -0. 012 -0. 018 -0. 012 -0. 020 -0. 019 -0. 018 -0. 026 -0. 025 -0. 024 -0. 023 -0. 021 -0. 026 -0. 004 -0. 011 -0. 003 -0. 002 -0. 003 -0. 009 -0. 026 0. 001 -0. 006 -0. 003 0. 009 -0. 028 -0. 025 -0. 010 0. 002 -0. 001 -0. 003 -0. 014 -0. 011 0. 006 -0. 001 -0. 023 -0. 025 -0. 012 -0. 019 0. 005 -0. 007 0. 010

Network Integrity Semi-Major Axis ~ 1 cm 24 -Hour Coordinate Spread 1 cm N & E 1. 5 cm Ellipsoid Ht

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