H 88 = h 83 – N 03

THE TECHNOLOGY SWEET SPOT SBAS: 2 M H, 6 M V, 0.3 M SMOOTHED H, CHEAP COMMERCIAL DGPS: FEW DM, $$ USCG BEACON: METER+, CHEAP CORS/OPUS: 2 CM h, 5 CM H POST PROCESSED DIFFERENTIAL LEVELING: 2-4 CM, LABOR/TIME INTENSIVE, $$$ GEODETIC LEVELING: mm, LABOR/TIME INTENSIVE, $$$$$ USER BASE RTK: 2-4 CM H, 2-5 CM V, REQUIRES INITIAL INVESTMENT, OUTCOME KNOWN IN FIELD RTN: 3-4 CM H, 5-7 CM V, REQUIRES INITIAL INVESTMENT(BUT ½ OF RTK), OUTCOME KNOWN IN FIELD AERIAL MAPPING:.10 M H,.20 M V, $$$ LIDAR: 0.10 – 0.3 M V SATELLITE IMAGERY: 0.5 METER H RESOLUTION, 3 M LOCATION, $$$ LOW ALTITUDE AERIAL IMAGERY: 2-4 CM H, 3-5 CM V, $$$ TERRESTRIAL LASER SCANNING: PROJECT SITES ONLY, M H, 0.02 M V, REQUIRES INITIAL INVESTMENT

≥200 RTN WORLDWIDE ≥80 RTN USA ≥37 DOT ACADEMIC/SCIENTIFIC SPATIAL REFERENCE CENTERS VARIOUS DOTS + MACHINE GUIDANCE COUNTY CITY GEODETIC SURVEYS (NC, SC) MANUFACTURERS VENDOR NETWORKS AGRICULTURE MA & PA NETWORKS RTN IN THE USA (JAN 2010)

RT FOR ORTHO HEIGHTS ADVANTAGES: LESS TIME- SECONDS ON POINT LESS LABOR- NO POST PROCESSING, MINIMAL PERSONNEL LESS EQUIPMENT – ONLY ONE RT UNIT NECESSARY WITH RTN = LESS $$$ USER KNOWS POSITION HAS BEEN CAPTURED AT REQUIRED PRECISION “GOOD” RELATIVE PRECISION IN HOMOGENEOUS TERRAIN AND USING THE SAME INITIALIZATION NEW GEOPOTENTIAL DATUM WILL BE ACCESSED THROUGH ACTIVE STATIONS DISADVANTAGES: LESS ACCURACY THAN LEVELING OR STATIC GNSS REQUIRES ADEQUATE USER KNOWLEDGE OF ALL EFFECTS ON RT GNSS POSITIONING

Access to accurate, reliable heights nationally- Geoid quality, New geopotential datum via active stations Consistent Standards across the nation- RTN validation, RTN guidelines Consistent Results. Data, technology, and tools that yield regardless of terrain and circumstances- Alignment to NSRS Maintainable system/process that will stand the test of time – ARP velocities, Integrity monitoring, User gets new datum via RTN RT IN RELATION TO GOALS OF NHMP

NEW APPLICATIONS IN ”HIGH-ACCURACY” REAL-TIME POSITIONING GIS – INFRASTRUCTURE, SIGNAGE, ENVIRONMENTAL, PHOTO CONTROL AGRICULTURE MACHINE GUIDANCE DEFORMATION MONITORING TECTONIC/SEISMIC STUDIES NAVIGATION TO/FROM PORTS REMOTE SENSING/MAPPING – LIDAR FAA – NAVIGATION, LANDING, TAXIING (WEATHER SCIENTISTS – CO-LOCATED RT IONO/TROPO SENSORS)

PRECISION VS. ACCURACY “PRECISION” IS A COMPUTED STATISTICAL QUANTITY TO THE SOURCE OF THE MEASUREMENT - ALIGNMENT TO THE RTN OR PASSIVE MARK BASE SHOWS PRECISION OF THE OBSERVATION (PER THE DATA COLLECTOR). “ACCURACY” IS A COMPUTED STATISTICAL QUANTITY TO THE REALIZATION OF THE DATUM - ALIGNMENT OF THE RTN OR PASSIVE MARK BASE TO THE NSRS SHOWS ACCURACY (PER ESTABLISHED METHODOLGY)

B ≥ 4 H & V, KNOWN & TRUSTED POINTS? B LOCALIZATION RESIDUALS-OUTLIERS? B DO ANY PASSIVE MARKS NEED TO BE HELD? RT BASE WITHIN CALIBRATION (QUALITY TIE TO NEAREST CALIBRATION POINT)? B SAME OFFICE & FIELD CALIBRATION USED? FYI: GNSS CAN PROVIDE GOOD RELATIVE POSITIONS IN A PROJECT WHILE STILL NOT CHECKING TO KNOWNS IN AN ABSOLUTE SENSE

BLUNDER CHECKING POINTS WITH OPUS-RS

NGS SINGLE BASE GUIDELINES LEGACY EQUIPMENT NO CELL COVERAGE NEW RT CLOSEST BASE NETWORKS MACHINE GUIDANCE AND PRECISION AGRICULTURE USE

RTN GUIDELINES FOR GNSS POSITIONING– WILL NOT SPECIFY OR DEFINE A STANDARD, BUT WILL HELP ADMINISTRATORS AND USERS TO BE AWARE OF ALL THE ISSUES INVOLVED WITH THIS NEW TECHNOLOGY 60+ CONTRIBUTORS: NGS ADVISORS DOT STATE GEODETIC SURVEYS GNSS MANUFACTURERS SRCs BLM, NPS

THOUGHTS ON ORTHO HEIGHTS ON RTN ARP LEVELING TO ARP CREATES A NEW BM EASILY USED IN HT MOD PRACTICES DENSIFIES GNSS ON BENCH MARKS = BETTER HYBRID GEOID MODEL ARP MONITORED 24/7/365 UNLIKE PASSIVE MARKS MANY STATE DOTs ARE LEVELING TO THEIR RTN ARP ROVER HEIGHTS STILL DEPENDENT ON GEOID MODEL FOR ORTHOS BY ESTABLISHING PASSIVE BMs AT RTN SITE, ELLIPSOID DIFFERENCE CAN PRODUCE ARP ORTHOS (IF DESIRED) – BUT THIS EFFECTIVELY GIVES A MEANS OF MONITORING THE PASSIVE BM USING THE RTN STATION BECAUSE THE ARP POSITION IS ALWAYS KNOWN.

NTRIP & RTCM- IMPROVING 3D POSITIONING WITH NEW MESSAGES

 Standard Solution (RMS:21 mm)  Optimized Solution (RMS:13 mm) RTCM Paper SC Herbert Landau, Xiaoming Chen, Adrian Kipka, Ulrich Vollath - Trimble Terrasat GmbH Improving RTK with RTCM Network Residual Messages 2 Positioning improved by up to a factor of 2 Initialization time reduced by 30%

RTN RESIDUAL RTCM 3.x MESSAGE TYPES

STATE SPACE RTCM 3.x MESSAGE TYPES

EMERGING NGS ACTIVITIES…..

POSSIBLE METHODS OF RTN VALIDATION OPUS-PROJECTS – NGS APPROVED PROGRAM TO VALIDATE A RTN ADJUSTMENT THAT WAS PERHAPS ACCOMPLISHED WITH GNSS MANUFACTURER’S SOFTWARE OR ANOTHER PROGRAM. OPUS-S – 3 OR 10% OF RTN ARE NGS CORS WHICH THEN GENERATE OPUS-S SOLUTIONS ON ALL OTHER RTN REFERENCE STATIONS. THESE CAN BE PUSHED TO NGS AND PUBLISHED AS 60 DAY PLOTS, OR MAINTAINED ON A PUBLIC SITE AT THE RTN ADMINISTRATION LOCALE. FIDUCIAL STATIONS - HIGH STABILITY MARKS ARE CONSTRUCTED WITHIN A RTN. GNSS STATIC PROVIDES X,Y,Z. GEODETIC LEVELING PROVIDES NAVD 88. STATIONS MAY BE BLUE BOOKED. USERS CAN THEN TEST THEIR ROVERS AT THE MARKS TO COMPARE THEIR RESULTS FROM THE RTN WITH THE PUBLISHED VALUES. PILOT PROGRAMS PLANNED IN OREGON AND LOUISIANA. LETTER OF CERTIFICATION - RTN ADMINISTRATOR SENDS A STATEMENT CERTIFYING THAT AS OF A PARTICULAR DATE THE RTN IS ALIGNED TO THE NATIONAL DATUM AT A CERTAIN LEVEL (2 CM LAT/LONG, 4 CM h ?) NGS REVIEW - NGS DOES A PERIODICAL REVIEW OF THE RTN STATIONS AND ADJUSTMENTS

IDOP VALUES – 4 CORS EXAMPLE BEST IDOP = 1 √ N THEREFORE, WITH 9 CORS, THE IDOP AT THE CENTROID WOULD BE.33, WITH 4 CORS IT WOULD BE.5 AT THE CENTROID ADDITION OF RMS OF DISTANCE TO CORS CONTRIBUTING TO THE SOLUTION GIVES FINAL UNITLESS NUMBER “IDOP” :THE SUBJECT OF A PAPER BY DRS. CHARLES SCHWARZ, TOM SOLER AND RICHARD SNAY APPLICATION FOR RTN?

ALL THESE COME INTO PLAY TO ENABLE THE STRUCTURE TO CLEAR THE BRIDGE! LMSL NAD 83 NAVD 88 BATHYMETRY CHART DATUM BRIDGE DYNAMICS BRIDGE DIMENSIONS SHIP SQUAT SHIP DIMENSIONS KNOW YOUR METADATA- UNIFYING THE VERTICALS TO A COMMON DATUM

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 Obstruction Charting Utilities Surveying Engineering Mapping Infrastructure

Motivating Force for a Network Application

Antenna Hardware Stainless Steel Mount For 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) = 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

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 Allowable 2-D RMSE r 95% = * RMSE r = (2.0* * *1.2) 1/2 = 2.4 cm* Allowable 1-D RMSE v 95% = *RMSE v = (2.0* * *2.4) 1/2 = 3.1 cm* Time (sec) Horizontal (cm) Vertical (cm) *(Local Accuracy 2 + Eccentricty 2 + System Design 2 ) 1/2

Station SCBY Vertical Axis to 0.014m

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

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

Practical Applications

Tidal Datum Transfer 2 mile transfer 0.05 ft uncertainty VRS Elevation (ft)Leveling (ft)Difference Mean/SDV0.001/0.008

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 Mean/SDV0.002/0.025

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

Ellipsoid Height Distortions of 3CM or Greater

Network vs OPUS – 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

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

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