Wisconsin Height Modernization Program WIHMP

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WisconsinHeight Modernization Program (WI-HMP)

• Improving the Vertical Component
• of the Geodetic Network
• Paul J. Hartzheim, P.E.

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Wisconsin Height Modernization Program

• Started by WisDOT in 1998 to improve the vertical
  component of Geodetic Control in Wisconsin
• Began with pilot project and has extended to 50
  percent coverage of WI
• Partners with the National Geodetic Survey (NGS)
• Developed WI-HMP standards to guide WI-HMP for
  data inclusion in the NSRS
• Provide training and technical assistance to
  WisDOT staff
• Support Research and Development activities
  funded by Congress
• Support Outreach activities in other states and
  regions

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Height Modernization Objectives

• Eliminate inconsistencies between horizontal and
  vertical control data and supplemental control
  where marks have been destroyed or are deemed
  unusable
• Utilize GPS technology as a cost effective
  positioning tool (achieve 2-cm positional
  accuracy)
• Decrease the cost of surveying required for
  transportation related projects
• Provide a much more accurate vertical database to
  a wide variety of data users throughout the state
• Complete initial efforts by 2011

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Funding and Management

• Funding
• State Transportation Funds
• FHWA State Planning Research Funds
• National Oceanic and Atmospheric Administration
  (NOAA) - Federal Congressional Earmark Funds
• Management Structure
• Geodetic Survey Supervisor
• Four Geodetic Specialists (all Project positions,
  2 - ETT Senior 2 ETT Advance)
• Three Limited Term Employees
• Up to 32 consultant staff personnel

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Height Modernization Layout
HARN station Primary Base Network Secondary
Base Network Local Base Network
Existing NGS Level line Decimated NGS Level
line New WI-HMP Level line
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Procedures for WIHMP
Four steps are necessary to complete each region
of WI (called a Phase) for WI-HMP

• Planning and Reconnaissance (First Year)
• Monumentation (Second Year)
• Geodetic Surveying (Third Year)
• Reduction, Adjustment, and Publication of data
  (Fourth Year)

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Planning and Reconnaissance

• State is divided into geographic regions (Phases)
• Search the NSRS for information on existing
  horizontal and vertical control
• Recover and evaluate all existing monumentation
  (published and non-published)
• Plan locations to supplement monumentation where
  deficiencies exist
• Hold outreach meetings with local officials to
  discuss plans and modify when necessary

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Monumentation

• Performed in the Summer/Fall of year prior to the
  year of the survey
• New monuments are 16-inch diameter, 8-foot deep
  pour-in-place concrete posts or disks set in
  stable structures
• Private sector firms have been used to construct
  monuments
• Monuments are described in accordance with the
  Federal Geodetic Control Subcommittee (FGCS)
  Blue Book standards
• Used to locate monuments, not replace them!

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WI-HMP Monumentation
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Geodetic Surveying for WI-HMP

• Geodetic (Conventional) Leveling
• Primary Global Positioning System (GPS) Survey
  Campaign (Static)
• Secondary and Local GPS Survey Campaign (Static)

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WI-HMP Geodetic (Conventional) Leveling

• Utilize digital leveling equipment with data
  recording capabilities of 0.0001 m
• Follow FGCS 2nd Order Class 1 specs
• Instrument collimation performed each day of
  observations
• 60 meters maximum sight lengths
• Balance Backsight/Foresights
• Double observe each section of leveling under
  different environmental conditions
• Use turning pins and staff supports
• Utilize All Terrain Vehicles (ATVs)

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Leveling with ATVs

• Defined by Wis. Stat. 340.01 (2G) as an
  engine-driven device which has a net weight of
  900 pounds or less
• Authorized for use along highways by Wis. Stat.
  23.33 (4) (c) 1m. Land Surveyors Exception
• Increases production up to 40.
• Average walking production 1.2 km/hr
• Average ATV production 1.7 km/hr

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WI-HMP Primary GPS SurveyBasic Observation
Guidelines

• At least 3 occupations of stations on different
  days
• 5 ½ hour occupations for each session one must
  have a different satellite constellation
• 3 weather (psychrometer and barometer) readings
  for each session
• Images or rubbings of stations are taken for each
  occupation

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WI-HMP Secondary and Local GPS Survey Basic
Observation Guidelines

• At least 2 occupations of stations on different
  days
• All adjacent stations must have a repeated
  baseline
• One hour occupations for each session each must
  have a different satellite constellation
• Two weather readings for each session
• Images or rubbings of stations are taken for each
  occupation

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Reduction, Adjustment, and Published Positions

• Bench Marks (BMs)
• FGCS 2nd Order - Class 1, Published on North
  American Vertical Datum of 1988 (NAVD 88)
• GPS Stations
• Horizontal FGCS B-order or 1st Order accuracy and
  GPS derived vertical 2-cm positional accuracy
  (not leveled). Published on North American Datum
  of 1983 (1997) (NAD 83 (1997)) and NAVD 88
• All published datasheets are available at
  www.ngs.noaa.gov

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Status of Completion
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WI-HMP RTK GPS Use and Benefits

• Establish horizontal and vertical coordinates for
  design and construction surveys
• 40 50 less time
• Less time needed for error analysis between GPS
  and leveling derived elevations
• All positions are easily re-established
• Reduce the need for any conventional leveling
• Instant coordinates

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Example of RTK BenefitState Agency

• WisDOT compared a static GPS survey and
  conventional leveling (before WI-HMP) verses a
  RTK GPS survey (after WI-HMP) for the
  establishment of photogrammetric targets for a
  highway improvement project
• Horizontal and Vertical (elevations) positions
  were all within 2 cm (.07)
• Static GPS w/Leveling 280 staff hours
• RTK GPS 30 staff hours
• WI-HMP with RTK provided over a 91 time savings!

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Example of RTK BenefitCounty Agency

• Digital Orthophotography field survey for
  accuracy check
• A survey was needed by a County to verify 10
  horizontal and vertical positions derived from
  digital orthos in one 36 square mile township
• It was estimated (from past projects) to take 24
  hours to perform these checks using conventional
  (static GPS, total station, and leveling)
  procedures before WI-HMP
• With WI-HMP in place, RTK GPS procedures were
  utilized to perform these checks in just 4 hours
• WI-HMP with RTK provided 61 time savings!

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WI-HMP Mark Maintenance
GPS Stations Orange 4x4 Plastic Guard Posts

• Installed 3 witness posts around each monument
• Established 866 number to report endangered,
  damaged, or destroyed monuments
• Created the Preservation of Geodetic Survey
  Stations Committee

Bench Marks White T Plastic Witness Posts
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Obstructed GPS Station
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WI-HMP Future

• Implement and integrate Wide-Area Real Time
  Kinematic GPS Network into WI-HMP
• Develop and implement CORS pilot project to test
  achievable versus desired accuracies
• Need to ensure 2-cm three-dimensional accuracy
• Resolve existing challenges
• Statewide communication
• Number of allowed users
• Protect base station locations
• Data accessibility (firewalls, communication
  charges, etc.)

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Construction of Marshfield CORS
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Construction of Marshfield CORS
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Construction of Marshfield CORS
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Construction of Marshfield CORS
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Construction of Marshfield CORS
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Construction of Wausau CORS
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Questions/Comments?