Upgrade Geodetic Control

Lead Agency

NOAA National Geodetic Survey.

Participating Jurisdiction

Hawaii

Goal

Upgrade geodetic control in Hawaii.

Objectives

• Establish a High Accuracy Reference Network (HARN)/ Cooperative Base Network (CBN) with 5- to 10-kilometer spacing.
• Establish a geodetic-quality leveling network.
• Establish an absolute gravity station with relative gravity stations.

Description

• Increase the densification by implementing a HARN/CBN network. Locate at least 20 to 25 marks already surveyed with the Global Positioning System (GPS) that would support the surveying and geographic information system (GIS) communities.
• Conduct geodetic leveling between the tidal benchmarks, Federal Base Network (FBN), HARN, CBN, and Continuously Operating Reference Station (CORS).
• Conduct one network adjustment on the vertical network and one on the GPS network to be included in the National Geodetic Survey’s Integrated Data Base.
• Conduct at least two absolute gravity and relative gravity measurements on the island where transportation is possible.
• Host training workshops on geodetic leveling and GPS observations.

The Hawaii GPS survey and geodetic leveling campaign will provide the horizontal and vertical integration and positional improvements required to support the diversity of GIS, engineering, geophysical, charting, and mapping applications required by NOS, other federal and local government agencies, and the private sector. The campaign will follow specifications consistent with the National Geodetic Survey’s Height Modernization initiative. NGS will conduct an integrated survey program to provide positional accuracies better than 1 centimeter in the horizontal and 2 centimeters in ellipsoid height components.

The only comprehensive geoid model for the Pacific is the National Imagery and Mapping Agency’s (NIMA) Earth Gravity Model 1996 (EGM 96), which exhibits uncertainties that can exceed 2 meters. Regional or local refined models will require a combination of high accuracy ellipsoid heights (2 centimeter) and absolute gravity measurements. Every attempt will be made to recover previously determined absolute gravity stations in Hawaii. Should the reconnaissance of these sites prove unsuccessful, new stations must be established.

Hawaii personnel will be heavily involved in all parts and phases of the project.

Outputs or Outcomes

• Positional accuracies better than 1 centimeter in the horizontal and 2 centimeters in ellipsoid height components.
• Better geoid model.
• Hawaii personnel trained in high accuracy GPS techniques and geodetic leveling.

Project Partners

State of Hawaii Department of Transportation, Hawaii Association of Land Surveyors, NOAA Center for Operational Oceanographic Products and Services, NOAA National Ocean Service, and the NOAA Pacific Services Center.