National Geodetic Survey

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The National Geodetic Survey (NGS) develops and maintains a national coordinate system, which provides the foundation for transportation, navigation, land record systems, mapping and charting efforts, defense operations, and a multitude of scientific and engineering applications. NGS products, services, and data support maritime navigation, aviation safety, hurricane evacuation routes, climate change activities, ocean observing, and more.

NGS highlights from fiscal year 2009 include:

  • Releasing a socioeconomic study that shows positioning services deliver benefits in the billions of dollars. The study, which was released to Congress and the public, was conducted by Leveson Consulting on the National Spatial Reference System (NSRS), Continuously Operating Reference Station (CORS) network, and Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project. Preliminary estimates indicate the annual benefits of the NSRS at $2.4 billion, CORS at $758 million, and the completion of the GRAV-D project at $282 million. CORS and GRAV-D benefits examined in this scoping study will set the stage for a full examination and validation of benefits in a full-blown socioeconomic study to be conducted later.  
  • Reaching the milestone of 100 million digital products served. Recent analysis of Web statistics suggested that NGS achieved this milestone in March 2009 by delivering 100 million digital geospatial products since Web analysis began in 2003.  These products include Continuously Operating Reference Station geographic positioning system data sets, electronic survey mark data sheets and geographic information system shape files, and Online Positioning User Service (OPUS) solutions. This analysis also revealed that NGS’s popular OPUS utility served its one-millionth solution report. The Web statistics and electronic delivery of NGS products and services related to the National Spatial Reference System show tremendous user demand for NOAA positioning products. 
  • Upgrading the Online Positioning User Service (OPUS) Web tool to allow users to share Global Positioning System survey positions. OPUS users are now provided with the option to publish their positions in the NGS database. This complements the traditional "bluebooking" method by which surveyors nationwide have strengthened the National Spatial Reference System (NSRS), the common foundation for mapping and engineering applications. OPUS provides a comparatively streamlined and homogeneous method for defining the location of monumented features such as tidal bench marks. OPUS is the most popular of the NGS suite of geodetic tools. Every month, users voluntarily submit approximately 20,000 survey data files, each of which are automatically processed using standard NGS data, software, and models to compute an accurate position. This OPUS upgrade will enhance user efforts to share work and personalize the NSRS by lowering the cost and effort involved for bluebooking and contracted surveys.
  • Submitting NGS positioning products – from 2000 to present – to the International Global Navigation Satellite System Service for inclusion with comparable products to create a new International Terrestrial Reference Frame released in 2009. Model upgrades and strategy changes made over the years have significantly improved estimates of satellite and station positions to the centimeter level; however, they have also made the full position history inconsistent. NGS has reanalyzed Global Positioning System (GPS) data collected from 1994 through 2007, resulting in a consistent position history and new position products. Data collected from the network are used for a variety of purposes, including precise GPS satellite positions, precise position of the tracking stations, and precise position of the Earth’s axis of rotation.
  • Developing gravity-based vertical datum in Puerto Rico and the Virgin Islands. In November 2008, NGS performed preliminary terrestrial gravity observations in Puerto Rico and the Virgin Islands with the establishment of one absolute gravity station in Puerto Rico and another on the Island of St. Thomas in the U.S. Virgin Islands. These new absolute gravity stations were used as control points for scheduled airborne gravity observations to support the creation of a vertical datum. The work in Puerto Rico and the Virgin Islands will test procedures and methodologies for conducting nationwide gravity collection, as defined in the Gravity for the Re-definition of the American Vertical Datum (GRAV-D) plan. Without a comprehensive, cohesive, and accurate gravity-based vertical datum, geographic positioning systems cannot be used to accurately determine elevations. 
  • Completing the Gulf Coast aerial gravity pilot project. NGS completed an aerial gravity survey along parts of the Gulf Coast to enhance VDatum in partnership with the U.S. Army Corps of Engineers. Coastal gravity data was collected along the Gulf Coast from the Alabama/Georgia state line to the border with Mexico. Applications that use VDatum include inundation modeling, ecosystem modeling, coastal management, hydrographic survey depths, and shoreline extracting from LiDAR data. VDatum is a free software tool developed jointly by NGS, the Office of Coast Survey, and the Center for Operational Oceanographic Products and Services
  • Developing software for processing Global Navigation Satellite System (GLONASS) data to support differential positioning between GLONASS receivers. This software will be embedded into the Online Positioning User Service (OPUS) so that users can submit U.S. Global Positioning System (GPS) or GLONASS data for precise positioning coordinates of where observations were collected. NGS will also develop software to compute the path of the GLONASS satellites as they orbit the Earth for a wide variety of satellite-based precise positioning activities. Incorporating GLONASS satellites into traditional GPS solutions enhances their accuracy and reliability because of the availability of more satellites to process a solution. For GPS receivers to provide accurate information, the precise location of positioning satellites as they orbit the Earth must first be determined. 
  • Developing draft versions of two real-time positioning guidelinesUser Guidelines for Classical Global Navigation Satellite Systems GNSS (Global Navigation Satellite Systems) Real-Time Positioning and Guidelines for Operating a Real-Time GNSS Network. In addition to NGS outreach efforts at more than 15 workshops across the country to market these products, the publications are also gaining the attention of trade magazines. NGS is working toward developing national guidelines for Real-Time Networks (RTNs) to ensure consistency, accuracy, and alignment of RTNs operated by a wide variety of entities across the nation.
  • Completing critical dam surveys. In October 2008, NGS and the Center for Operational Oceanographic Products and Services performed Global Positioning System and leveling surveys on a dam connecting Massena, New York, to Ontario, Canada. This dam is jointly owned by the U.S. and Canada. A reimbursable agreement between NOS and Ontario Power of Canada was signed prior to the survey. Dam flows are computed by using water-level gauge measurements from six critical water-level gauging stations. The waters used for power generation are shared equally by both countries. Many of the original primary benchmarks were destroyed or damaged over the years. The last precision survey establishing quality referenced heights for the gauging reference marks was performed by NGS in 1969.
  • Cultivating a partnership with the Mongolian government to support geospatial capabilities. NGS scientists traveled to Mongolia in February 2009 to support Mongolia’s geospatial capabilities. Over a two-week period, NGS met and interviewed Mongolian government officials (including Agency for Land Administration, Geodesy and Cartography personnel and the Minister for the Ministry of Roads, Transportation, Construction, and Urban Development) and representatives of the Millennium Challenge Account–Mongolia, on the status of Mongolia’s existing geospatial capabilities. These meetings focused on the Mongolian geodetic infrastructure and how modern remote sensing methodologies can contribute to performing accurate land parcel mapping for private land ownership initiatives. NOAA was asked by the Millennium Challenge Account–Mongolia to provide geodetic expertise to assist with further developing their geospatial infrastructure in support of the privatization and capitalization of land assets held by Mongolians.

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