© 2009 Herbert, Rowland & Grubic, Inc. OPUS and VRS for QA Surveys of the PAMAP Program Eric M. Orndorff, MS, PLS Zach Lupold, BS Great Lakes Region Height Modernization Consortium Meeting April 13, 2011

© 2009 Herbert, Rowland & Grubic, Inc. Overview Pre-OPUS/VRS (conventional, radio-based RTK) Point-to-point wireless RTK RTN (VRS network and point solutions)

© 2009 Herbert, Rowland & Grubic, Inc. Overview Point-to-point wireless RTK PAMAP QA Surveys Evolution –Point-to-point wireless RTK and OPUS –RTN (VRS network and point solutions)

Point-to-point wireless RTK Background © 2009 Herbert, Rowland & Grubic, Inc.

Point-to-point wireless RTK 2005 research (academic) –Investigate vertical accuracy as a function baseline lengths and occupation times –Double run, triple wire line of levels run through marks for determining their orthometric heights as related to NAVD research (random/reality) –Investigate NAVSTAR/GLONASS versus NAVSTAR only solutions –Varying baseline distances when comparing 1 st and 2 nd observations (TIDAL BASIC and GIS96 base stations) –Elevations vary from 6’ to 450’; baselines vary up to 18 miles

© 2009 Herbert, Rowland & Grubic, Inc. Point-to-point wireless RTK 1 Sec.3 Sec.10 Sec.60 Sec.120 Sec.180 Sec.240 Sec.300 Sec. 6k k k k k k k k Research Results

© 2009 Herbert, Rowland & Grubic, Inc. Point-to-point wireless RTK 2007 Project Area Wireless (point-to-point) RTK: –Trimble R8 GNSS base and rover –Airlink CDMA modem –Verizon Wireless 52 photo-identifiable points 110 Sq. Mi. Area Support orthophotography for planning of the “Green Line” corridor.

© 2009 Herbert, Rowland & Grubic, Inc. Point-to-point wireless RTK 2007 Project Area

© 2009 Herbert, Rowland & Grubic, Inc. Point-to-point wireless RTK 2007 Research Results 1st. Observation Minus 2nd. Observation Squared Mean of Observations U.S. Survey Ft. Maryland SPC NAD 83 (1986) U.S. Survey Ft.NAVD 88 NORTHINGEASTINGELEVATIONPOINT #NORTHINGEASTINGELEVATION SUM RMSE RMSENEElev. NAVSTAR vs NAVSTAR/GLONASS (n = 52) Project vs VRS (n = 12)

© 2009 Herbert, Rowland & Grubic, Inc. Point-to-point wireless RTK 2005 research conclusions –Investigate stations at 8 km, 14 km 18 km –Re-observe stations during specific optimum satellite availability and geometry conditions –Time does not appear to affect accuracy –Can achieve sub-2 cm accuracy out to 20 km 2007 research conclusions –No clear degradation over distance –RMSE reveals vertical to be 2x less accurate than horizontal –Successful methodology for small scale mapping projects

PAMAP QA Surveys Evolution © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP QA Surveys Evolution First Phase ( ) –OPUS control –Point-to-point wireless RTK (~90%) –Static Baselines (~10%) Second Phase ( ) –RTN (VRS network and point solutions)

PAMAP Phase 1 PAMAP Orthophotography © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 1 PAMAP LIDAR © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 1 © 2009 Herbert, Rowland & Grubic, Inc. Relied on Wireless RTK –Utilized Airlink CDMA modems –Verizon wireless –Job required surveying random points over large areas –RTN network not yet developed in the project area –Used OPUS for control at base locations

PAMAP Phase 1 © 2009 Herbert, Rowland & Grubic, Inc.

Phase 1 Methodology Project area was broken into blocks Two independent one person teams Both team members set up an RTK base at a pre-chosen location For redundancy, each survey point was observed twice using a baseline vector from each control point The two sets of coordinates were averaged in the office via Excel spreadsheet © 2009 Herbert, Rowland & Grubic, Inc.

Phase 1 Methodology © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 1 Advantages of Wireless RTK –Range only limited by satellite/atmospheric conditions –Allows user input/control –No subscription fees other than wireless plan –CDMA format more available in rural areas © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 1 Disadvantages of Wireless RTK –Requires user to visit base location –Possibility of theft if base left unattended –Possibility of user errors in processing base data –Hardware intensive –CDMA modems were not designed for outdoor use  Succumbed to disadvantages to realize efficiencies in field work production (Static networks and radio-based RTK are cost prohibitive) © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 2 QA/QC of 2008 Orthos (second generation) and 2008 LIDAR Reduction of checkpoints density due to funding restraints Well established VRS network at this time © 2009 Herbert, Rowland & Grubic, Inc.

VRS Network (KeyNet) © 2009 Herbert, Rowland & Grubic, Inc.

Phase 2 Methodology Primarily a single one person crew Checkpoints were observed twice with a different initialization each time OPUS RS was used to process static observations where data service was unavailable Some points were also observed with OPUS RS (Rapid Static) for quality control © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 2 Advantages of VRS –Eliminates base station setup/teardown time –No risk of base theft –Eliminates major sources of user error –Less hardware intensive –Built in redundancy “network solution” –Real time results with little post processing © 2009 Herbert, Rowland & Grubic, Inc.

PAMAP Phase 2 Disadvantages of VRS –Requires monthly access fee –Little user input –Data interruptions due to server failure-Rare  Advantages outweigh disadvantages © 2009 Herbert, Rowland & Grubic, Inc.

VRS and OPUS RS Comparison VRS OBSERVATIONS OPUS RS OBSERVATIONS FIRST OBSERVATION MINUS SECON OBSERVATION FIRST OBSERVATION MINUS SECON OBSERVATION SQUARED PA SPC NAD 83 (1986) U.S. Survey Ft.NAVD 88PA SPC NAD 83 (1986) U.S. Survey Ft.NAVD 88 U.S. Survey Ft. POINT #NORTHINGEASTINGELEVATIONNORTHINGEASTINGELEVATIONNORTHINGEASTINGELEVATION NORTHINGEASTINGELEVATION B C C C H O O O SC-14H SC-2H SC-3H SC-5H SUM RMSE © 2009 Herbert, Rowland & Grubic, Inc.

What’s Next? © 2009 Herbert, Rowland & Grubic, Inc.

What’s Next? © 2009 Herbert, Rowland & Grubic, Inc.

Nebraska USDA LIDAR QA/QC 3400 square mile project area 300 checkpoints Used a combination of VRS and static GPS OPUS used as a check on VRS outside of the network –Longest VRS baseline Miles –ΔH.036 ΔV.029 © 2009 Herbert, Rowland & Grubic, Inc.

Questions & Discussion Contact: Eric Orndorff at Zach Lupold at