Alabama Height Modernization Project, NAD Alabama Height Modernization Project, NAD 83(2011), and GEOID 12 in Alabama 83(2011), and GEOID 12 in Alabama

Overview of Height Modernization ProjectOverview of Height Modernization Project

NAD 83(2011) AdjustmentNAD 83(2011) Adjustment

GEOID 12GEOID 12

Alabama Height ModernizationAlabama Height Modernization

Congressional Funding through NOAA – NGSCongressional Funding through NOAA – NGS

Alabama Department of Revenue (ADOR) is Alabama Department of Revenue (ADOR) is grant recipientgrant recipient

Surveying Tasks Delegated to Alabama Surveying Tasks Delegated to Alabama Department of Transportation (ALDOT)Department of Transportation (ALDOT)

Work began in 2005 and will be finished by Work began in 2005 and will be finished by the end of 2012the end of 2012

Improving Heights obtained with GPS Improving Heights obtained with GPS or Improving the GEOID Modelor Improving the GEOID Model

1 -Establish Network of marks with GPS to get good 1 -Establish Network of marks with GPS to get good Ellipsoid HeightsEllipsoid Heights

2 – Establish good leveled heights on marks with 2 – Establish good leveled heights on marks with good ellipsoid heightsgood ellipsoid heights

3 – Utilize GPS benchmarks in development of new 3 – Utilize GPS benchmarks in development of new GEOID modelsGEOID models

Height Modernization ActivitiesHeight Modernization Activities

GPS Surveys using procedures from NOS NGS 58 GPS Surveys using procedures from NOS NGS 58 & 59 – 2 cm repeatable elevations from GPS. & 59 – 2 cm repeatable elevations from GPS. (1998 Report to Congress.)(1998 Report to Congress.)

First and Second Order Leveling to support NOS First and Second Order Leveling to support NOS NGS 58 & 59 Surveys, improve the GEOID Model NGS 58 & 59 Surveys, improve the GEOID Model for Alabama, and to establish NAVD 88 heights at for Alabama, and to establish NAVD 88 heights at the CORS ARP.the CORS ARP.

CORS – Establish a state-wide CORS network to CORS – Establish a state-wide CORS network to serve as the National Spatial Reference System serve as the National Spatial Reference System (NSRS) for the state in the future and to provide (NSRS) for the state in the future and to provide data for monitoring crustal motion.data for monitoring crustal motion.

HARN ObservationHARN Observation

Planning began in October, 2003Planning began in October, 2003 Joint Project with NGS, ASPLS, ALDOTJoint Project with NGS, ASPLS, ALDOT Observations scheduled for the week of Observations scheduled for the week of

June 21, 2004June 21, 2004 125 total marks observed125 total marks observed 104 marks observed in Alabama104 marks observed in Alabama

2003 2006 2003 2006

Leveling Projects to support Primary and Leveling Projects to support Primary and Secondary GPS Projects and establish NAVD 88 Secondary GPS Projects and establish NAVD 88

Heights on ARP of CORSHeights on ARP of CORS

Phase I – FBN LevelingPhase I – FBN Leveling Second Order Class I LevelingSecond Order Class I Leveling 545 miles w/ 324 new Benchmarks545 miles w/ 324 new Benchmarks Field work is complete and has been published by NGS.Field work is complete and has been published by NGS.

Phase II – CORS LevelingPhase II – CORS Leveling Second Order Class I Leveling to Antenna Reference Plane Second Order Class I Leveling to Antenna Reference Plane

(ARP) of CORS sites(ARP) of CORS sites Field work complete and approximately 75% of the data Field work complete and approximately 75% of the data

has been published.has been published. Includes an additional 40 miles of First Order Class II Includes an additional 40 miles of First Order Class II

leveling to verify Dauphin Island line.leveling to verify Dauphin Island line. Includes ties to tidal benchmarks at Dauphin Island and Includes ties to tidal benchmarks at Dauphin Island and

Mobile DocksMobile Docks Phase II Leveling Total = 282 milesPhase II Leveling Total = 282 miles

Improved GEOIDImproved GEOID Primary Base Network of FBN Primary Base Network of FBN Marks – Horizontal and Marks – Horizontal and vertical marks established on vertical marks established on a 40 to 50 kilometer grid.a 40 to 50 kilometer grid.

Leveling projects will ensure Leveling projects will ensure each FBN Station has a First each FBN Station has a First or Second Order Elevation. or Second Order Elevation. These marks will be the These marks will be the foundation for the NOS NGS foundation for the NOS NGS 58 & 59 surveys.58 & 59 surveys.

Additional leveling to CORS Additional leveling to CORS and other GPS marks along and other GPS marks along the route add more GPS the route add more GPS Benchmarks for the model.Benchmarks for the model.

More elevations on good GPS More elevations on good GPS Marks = better Geoid Model Marks = better Geoid Model which results in improved which results in improved GPS ElevationsGPS Elevations

2003 2003 20122012

GEOID03 = 181 MarksGEOID03 = 181 Marks GEOID12 = 407 MarksGEOID12 = 407 Marks

2003 2003 20122012

Additional GPS Benchmarks included in GEOID12Additional GPS Benchmarks included in GEOID12

Leveling ProjectsLeveling Projects

- FBN Leveling- FBN Leveling- Height Mod Survey- Height Mod Survey- CORS- CORS- Tide Gauges- Tide Gauges- Ties to MDOT- Ties to MDOT Leveling Leveling

Project “A”Project “A”Height Mod SurveyHeight Mod Survey

GPS Survey to GPS Survey to establish 2 cm establish 2 cm

heightsheights

NOS NGS 58 and NOS NGS 58 and 59 Survey for Local 59 Survey for Local

Base StationsBase Stations

Leveling to HARN Station Leveling to HARN Station 49-1549-15

Direct tie from existing First Direct tie from existing First Order Line along US 45 to Order Line along US 45 to the new MDOT line along the new MDOT line along

US 98US 98

Leveling to Leveling to CORS site AL90CORS site AL90

Direct tie to Direct tie to MDOT levelingMDOT leveling

Direct tie to Tide Direct tie to Tide Gauge at Mobile Gauge at Mobile

DocksDocks

Establish Establish elevation on NGS elevation on NGS

Tide Gauge Tide Gauge Commemorative Commemorative

MarkMark

Leveling to CORS site ALDILeveling to CORS site ALDI

Spur to Bayou La BatreSpur to Bayou La Batre

Spur to Industrial ParkSpur to Industrial Park

Tie to Tide Gauge at Tie to Tide Gauge at Dauphin IslandDauphin Island

New minus Old Comparison along Dauphin Island Level lineNew minus Old Comparison along Dauphin Island Level line

Leveling to CORS site Leveling to CORS site ALFO in FoleyALFO in Foley

Direct tie to MDOT lineDirect tie to MDOT line

CORS LevelingCORS Leveling

In Louisiana, the system In Louisiana, the system of benchmarks had been of benchmarks had been deemed “unreliable”deemed “unreliable”

Transfer NAVD 88 Transfer NAVD 88 orthometric heights to orthometric heights to CORS ARPCORS ARP

Allow CORS network to Allow CORS network to serve as the vertical serve as the vertical control for areas of control for areas of subsidencesubsidence

Tide Gauges directly tied toTide Gauges directly tied toDauphin Island CORSDauphin Island CORS

Tidal BenchmarkTidal Benchmark

- Tide Gauges are tied to the Tidal Benchmarks. Each site has several - Tide Gauges are tied to the Tidal Benchmarks. Each site has several marks in close proximity to the gauge.marks in close proximity to the gauge.- Establish First or Second Order NAVD 88 Height at the Tidal Benchmark to - Establish First or Second Order NAVD 88 Height at the Tidal Benchmark to provide an accurate tie to Tidal Datum.provide an accurate tie to Tidal Datum.- Establish NAVD 88 Height at the CORS ARP- Establish NAVD 88 Height at the CORS ARP

NOAA Tide GaugeNOAA Tide Gauge

Dauphin Island CORSDauphin Island CORS

CORS VelocitiesCORS Velocities EstimatedEstimated AL92 in Bay Minette - VZ = -0.0008 m/yrAL92 in Bay Minette - VZ = -0.0008 m/yr ALDI on Dauphin Island - VZ = -0.0008 m/yr ALDI on Dauphin Island - VZ = -0.0008 m/yr ALFO in Foley - VZ = -0.0008 m/yr ALFO in Foley - VZ = -0.0008 m/yr ALCT in Citronelle - VZ = -0.0008 m/yrALCT in Citronelle - VZ = -0.0008 m/yr AL84 in Grove Hill - VZ = -0.0008 m/yrAL84 in Grove Hill - VZ = -0.0008 m/yr ALEB in Brewton - VZ = -0.0008 m/yrALEB in Brewton - VZ = -0.0008 m/yr

ComputedComputed AL90 in Mobile - VZ = -0.0016 m/yr (comp)AL90 in Mobile - VZ = -0.0016 m/yr (comp) PCLA in Pensacola - VZ = -0.0015 m/yr (comp)PCLA in Pensacola - VZ = -0.0015 m/yr (comp)

Affects of CORS Affects of CORS Adjustment in Adjustment in Southwest Alabama.Southwest Alabama.

Horizontal shifts seem Horizontal shifts seem to be consistent with to be consistent with the entire state (south the entire state (south and east)and east)

Vertical shifts varyVertical shifts vary

No dramatic changesNo dramatic changes

When do we change When do we change positions?positions?

CORS PositioningCORS Positioning

NGS no longer provides OPUS solutions using the NGS no longer provides OPUS solutions using the NAD 83(96) epoch. As of July 15, all OPUS NAD 83(96) epoch. As of July 15, all OPUS solutions are NAD 83(2011)solutions are NAD 83(2011)

ALDOT is currently using the NAD 83(96) epoch ALDOT is currently using the NAD 83(96) epoch for RTK broadcasts and will update to NAD 83 for RTK broadcasts and will update to NAD 83 (2011) soon. No dates have been set as of yet.(2011) soon. No dates have been set as of yet.

Email sent out on July 3, 2012 seeking user input.Email sent out on July 3, 2012 seeking user input. Coordinate updates will be coordinated with Coordinate updates will be coordinated with

Florida DOT, Tennessee DOT, and Mississippi.Florida DOT, Tennessee DOT, and Mississippi.

NAD 83 (2007) Adjustment of the Passive NAD 83 (2007) Adjustment of the Passive NetworkNetwork

2007 Adjustment did not seem to “fit” very well 2007 Adjustment did not seem to “fit” very well on static sessions.on static sessions.

Group of marks that were excluded from the Group of marks that were excluded from the adjustment in Lawrence County – resolved.adjustment in Lawrence County – resolved.

Group of marks in Jackson County with dramatic Group of marks in Jackson County with dramatic horizontal shifts – needs more reviewhorizontal shifts – needs more review

Suspected ellipsoid height problems in Southwest Suspected ellipsoid height problems in Southwest Alabama – needs more reviewAlabama – needs more review

NAD83 (2011) should be the best fit possible NAD83 (2011) should be the best fit possible between the passive marks and CORS.between the passive marks and CORS.

Future of Height Modernization in AlabamaFuture of Height Modernization in Alabama

All funding has been depleted and the possibility All funding has been depleted and the possibility of additional funding is slim at best.of additional funding is slim at best.

We will continue processing all leveling data and We will continue processing all leveling data and complete all outstanding projects for submission complete all outstanding projects for submission to NGS.to NGS.

Initiating mark maintenance program for Initiating mark maintenance program for benchmark resets where marks are in danger of benchmark resets where marks are in danger of being disturbed.being disturbed.

GEOID improvements – OPUS DB? GRAV-D?GEOID improvements – OPUS DB? GRAV-D?

Draft Real Draft Real Time Time

Positioning Positioning GuidelinesGuidelines

Questions, Comments?Questions, Comments?John D. Russell, PLSJohn D. Russell, PLSAlabama Department of TransportationAlabama Department of TransportationDesign Bureau – Location SectionDesign Bureau – Location Section334-242-6139 office334-242-6139 office russellj@dot.state.al.us

www.iheep2012.comwww.iheep2012.com