Geodetic Control Subcommittee 1999 Report


The Federal Geodetic Control Subcommittee (FGCS) of the Federal Geographic Data Committee exercises government-wide leadership in coordinating the planning and execution of geodetic surveys, in developing standards and specifications for these surveys, and in the exchange of geodetic survey data and technical information. FGCS coordinates Federal agencies' aspects of surveying that are governmental responsibilities. These responsibilities include standards setting, testing new geodetic instrumentation and operational systems, coordination of user agency requirements, and dissemination of government data to user agencies.

The FGCS acts to ensure that the Global Positioning System (GPS) will continue to meet the positioning needs of the Federal civilian community and works to strengthen the ties between the GPS positioning and navigation communities. This responsibility will be implemented through its role as GPS Interagency Advisory Council (GIAC) to the Department of Transportation PosNav Executive Committee.

 

Goal One: Increase the awareness and understanding of the vision and concepts of NSDI through outreach and education

Objective:

Continue to provide public access to information on aspects of geodetic surveying that are responsibility of civilian Federal agencies

- Action:

The FGCS Web site was refurbished on the model of the FGDC Web site:

http://www.ngs.noaa.gov/FGCS/

Objective:

Continue to identify and address issues associated with Global Positioning Systems (GPS) Modernization.

- Action:

Presented a set of workshops including:

- GPS-Derived Orthometric Heights Workshops - four presented

- Continuously Operating Reference Station (CORS) Workshops - three presented

- Action:

In conjunction with preparing the National Oceanic and Atmospheric Administration (NOAA) congressionally mandated Height Modernization Study, follow-up forums were held in California and North Carolina to provide information to and receive input from diverse interested constituency.

Objective:

Continue to identify and address issues associated with positioning accuracy, techniques, and reference frames.

- Action:

Presented a set of workshops including:

- Geospatial Positioning Accuracy Standards - two presented

- Development, Implementation, and Future of the National Spatial Reference System - six presented

Objective:

Evaluate surveying systems, including the instrumentation, hardware, software, and procedures that comprise that system.

- Action:

Tested three GPS receivers: Leica System 500 and the Javad Legacy and Regency.

- Action:

FGCS has been able to keep up with the preliminary letters but there is a backlog of final reports. Reflecting the manufacturers’ concern with FGCS getting the reports completed on a timely basis, Trimble has written two sponsor-supplied summary reports for their recently tested equipment. Because the tests are generally driven by the manufacturers and not from within the Federal agencies, the intent now is to shift responsibility onto the manufacturers for producing the final reports. FGCS will provide a template for the manufacturers to fill in, with place reserved for FGCS final comments.

- Action:

A new web site was established to provide access to the testing schedule and test results and can be accessed by the following web address:

http://www.ngs.noaa.gov/FGCS/instruments/reports.htm

- Action:

Updated standard operational procedures, forms, and documentation by putting the Deliverables List for GPS Instrument Tests and Recommended Observation Schedule on the Web.

Goal 2: Develop common solutions for discovery, access, and use of geospatial data in response to the needs of diverse communities

Objective:

Continue to provide access, documentation, and guidance regarding Continuously Operating Reference Station (CORS)

- Action:

Developed, implemented, and enhanced User Friendly CORS (UFCORS) to allow users to:

- Obtain CORS GPS data for an exact time interval specified in international or local time,

- Choose a sampling rate for the requested data,

- Specify how the data should be compressed to speed data transfer to the user,

- Receive the requested information within a few minutes,

- Obtain CORS log files automatically,

- Retrieve adopted NAD 83 and ITRF positions and velocities for the CORS sites automatically,

- Retrieve the highly accurate GPS orbits calculated by International GPS Service for Geodynamics (IGS), as well as the "broadcast" GPS orbits automatically, and

- Obtain associated NGS data sheets automatically.

http://www.ngs.noaa.gov/CORS/

Objective:

Continue to identify and address issues associated with Global Positioning Systems (GPS) Modernization.

- Action:

Provided a position paper to the U.S. Department of Transportation PosNav Executive Committee on the selection and character of the GPS civil signal and frequencies.

http://www.ngs.noaa.gov/FGCS/info/giacmem990430.html

 

Goal 3: Use community-based approaches to develop and maintain common collections of geospatial data for sound decision-making

Objective:

Monitor compatibility of Federal fixed reference stations with NAD 83 and their relationship to the development of a single Continuously Operating Reference Station (CORS) system to meet the requirements of Federal GPS post-processing procedures. On going.

- Action:

Thirty-three Continuously Operating Reference Stations (CORS) to be brought online, resulting in a total of 165 CORS.

- Action:

Developed Cooperative CORS - a method to electronically link via the Internet to CORS which are not part of the National CORS network. The National CORS are those stations meeting NOAA geodetic standards for installation, operation and data distribution. The Cooperative CORS will supplement the National CORS network by providing a dense system of reference stations to meet local needs.

http://www.ngs.noaa.gov/CORS/Coop/

Objective:

Ongoing participation in the nationwide augmentation of US Coast Guard conversion of US Air Force Ground Wave Emergency Network (GWEN) sites to facilitate Nationwide Differential GPS (NDGPS) primary coverage efforts.

- Action:

Provided input regarding siting of NDGPS sites in interior of Alaska as requested by Department of Transportation and U.S. Coast Guard.

Objective:

Participation in the assembly of geospatial resources for disaster response and management. Specifically, develop a scoping of the potential for geospatial assistance for disaster management, including other Federal delivery programs.

- No Action:

This objective could not be adequately addressed and is now on hold.

Objective:

Ongoing development, publishing, and maintenance of accuracy, collection, content, transfer, and archive standards for geodetic, land and resource surveys, and their related metadata. Promote the use of these standards by Federal, state, and local levels of government and the private sector.

- Action: In support of development of the FGCS sponsored Geospatial Positioning Accuracy Standard, Part 2: Standards for Geodetic Networks, documentation of field specifications

NOS NGS-58 - Guidelines for Establishing GPS-Derived Ellipsoid Heights

is on Web site:

http://www.ngs.noaa.gov/PUBS_LIB/NGS-58.html

- Action:

Drafted specifications for Federal Base Network re-observations, 2 cm horizontal and 2 cm ellipsoid height accuracy standards, NGS Web site:

http://www.ngs.noaa.gov/ADVISORS/FBN/GPSmanual/

- Action:

Disposition of the approval process for updates to the Input Formats and Specifications of the National Geodetic Survey Data Base (Blue Book) was relegated to the Methodology Work Group. This resulted in lessening the burden on FGCS as a whole and accelerating the approval process. The Blue Book may be accessed at:

http://www.ngs.noaa.gov/FGCS/tech_pub.html

- Action:

After due consideration the FGCS membership chose not to propose the Global Positioning System (GPS) Receiver Independent Exchange (RINEX) format as an FGDC standard. RINEX is recognized as a defacto industry standard.

Objective:

Ongoing participation in the nationwide implementation of NAVD 88 and in the development of the Nation's geodetic height system using GPS. Ongoing.

- Action:

The GPS-Derived Orthometric Heights Guidelines have been drafted. Guidelines for Establishing GPS-Derived Ellipsoid Heights, Some changes will be made based on recent studies