Improving Surveying Accuracy and Efficiency in Connecticut: An Accuracy Assessment of GEOID03 and GEOID09

Details

• Creators:
  Meyer, Thomas H. ; Baron, Robert
• Corporate Creators:
  University of Connecticut ; Connecticut Transportation Institute
• Corporate Contributors:
  Joint Highway Research Advisory Council ; Connecticut. Dept. of Transportation
• Subject/TRT Terms:
  Accuracy Data Collection GEOID03 GEOID09 Geoid Modeling Global Positioning System GPS Height Hybrid Geoid Models NAVD 88 OPUS Orthometric Heights Research Hub Surveying

  More +
• Publication/ Report Number:
  JHR 10-323
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Connecticut
• TRIS Online Accession Number:
  01605591
• Edition:
  Final Report
• Corporate Publisher:
  University of Connecticut
• NTL Classification:
  NTL-ENERGY AND ENVIRONMENT-Environment Impacts
• Abstract:
  Comparing published NAVD 88 Helmert orthometric heights of First-Order bench marks against GPS-determined orthometric heights showed that GEOID03 and GEOID09 perform at their reported accuracy in Connecticut. GPS-determined orthometric heights were determined by subtracting geoid undulations from ellipsoid heights obtained from a network least-squares adjustment of GPS occupations in 2007 and 2008. A total of 73 markers were occupied in these stability classes: 25 class A, 11 class B, 12 class C, 2 class D bench marks, and 23 temporary marks with transferred elevations. Adjusted ellipsoid heights were compared against OPUS as a check. We found that: the GPS-determined orthometric heights of stability class A markers and the transfers are statistically lower than their published values but just barely; stability class B, C and D markers are also statistically lower in a manner consistent with subsidence or settling; GEOID09 does not exhibit a statistically significant residual trend across Connecticut; and GEOID09 out-performed GEOID03. A "correction surface" is not recommended in spite of the geoid models being statistically different than the NAVD 88 heights because the uncertainties involved dominate the discrepancies. Instead, it is recommended that the vertical control network be re-observed. We tested networks in which no phase-center variations were applied and in which all vectors (including "substandard" vectors) were included. We found that PCV cannot be ignored and that including substandard vectors did not affect the results.
• Format:
  PDF
• Funding:
  Project 06-10
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f792cde34eec3e3a416a7c817a193b2bdcda1806e06ada2d4805aaac13519c3a
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/34447/dot_34447_DS1.pdf
• File Type:
  [PDF - 1.41 MB ]