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NOAA/NGS Continuously Operating Reference Station (CORS)

browse graphicNGDC Archive of NGS CORS data
The National Geodetic Survey (NGS), an office of NOAA's National Ocean Service, manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries. Surveyors, GIS users, engineers, scientists, and the public at large that collect GPS data can use CORS data to improve the precision of their positions. CORS enhanced post-processed coordinates approach a few centimeters relative to the National Spatial Reference System, both horizontally and vertically. The CORS network is a multi-purpose cooperative endeavor involving government, academic, and private organizations. The sites are independently owned and operated. Each agency shares their data with NGS, and NGS in turn analyzes and distributes the data free of charge. As of March 2014, the CORS network contains almost 2000 stations, contributed by over 200 different organizations, and the network continues to expand. The National Geophysical Data Center (NGDC) is the designated archive of the NGS CORS data set. NGDC utilizes NOAA's Comprehensive Large Array-data Stewardship System (CLASS) infrastructure to archive and distribute CORS data.

Cite this dataset when used as a source.

Search and Download
Distribution Formats
  • ASCII (Version: 2.11)
    • File Compression: GNU zip compression (gzip)
  • binary (Version: Not applicable)
    • File Compression: GNU zip compression (gzip), tar file format package
Distributor DOC/NOAA/NOS/NGS > National Geodetic Survey, NOS, NOAA, U.S. Department of Commerce
Point of Contact DOC/NOAA/NOS/NGS > National Geodetic Survey, NOS, NOAA, U.S. Department of Commerce
(301) 713-3191
ngs.cors@noaa.gov
General Documentation
Originator
  • DOC/NOAA/NOS/NGS > National Geodetic Survey, National Ocean Service, NOAA, U.S. Department of Commerce
Publisher
    Publisher information not available.
Date(s)
  • publication: 1994-04-22
Dataset Progress Status ongoing
Data Update Frequency: Daily
Supplemental Information: The United States operates the Global Positioning System (GPS). The term Global Navigation Satellite Systems (GNSS) has been created to reference all navigation satellite systems. GNSS encompasses the U.S. GPS system, the Russian Federation GLONASS system, and any future systems such as Europe's Galileo or China's Compass.
Purpose: The CORS data set enables users to attain centimeter-level positioning for points of interest and can be used to measure crustal motion, moisture content for the lower atmosphere, and total electronic content in the upper atmosphere. NGS publishes coordinates for CORS in several reference frames. This includes the current global reference frame from the International GNSS Service (IGS), and with respect to the National Spatial Reference System (NSRS) realizations of the North American Datum of 1983 (NAD 83) as defined by NGS. Reference frames are updated periodically as according to policy: http://geodesy.noaa.gov/INFO/Policy/CORS-coordinate-policyv4_20Dec2011.pdf
Use Limitations
  • These data are considered raw and have not been subjected to the NOAA's quality control or quality assurance procedures. They are released for limited public use as preliminary data to be used only with appropriate caution. NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
Time Period: 1994-02-01  to  Present
Spatial Bounding Box Coordinates:
N: 90.00
S: -90.00
E: 180.00
W: -180.00
Spatial Coverage Map:
Themes
  • EARTH SCIENCE > Solid Earth > Geodetics
  • EARTH SCIENCE > Solid Earth > Geodetics > Coordinate Reference Systems
  • EARTH SCIENCE > Solid Earth > Geodetics > Coordinate Reference Systems > Country/Regional Coordinate Reference System
  • EARTH SCIENCE > Solid Earth > Geodetics > Coordinate Reference Systems > Global Coordinate Reference System
  • EARTH SCIENCE > Solid Earth > Geodetics > Ellipsoid Characteristics
  • EARTH SCIENCE > Solid Earth > Geodetics > Geoid Characteristics
  • EARTH SCIENCE > Solid Earth > Geodetics > Control Surveys
  • EARTH SCIENCE > Solid Earth > Geodetics > Crustal Motion
  • EARTH SCIENCE > Solid Earth > Geomorphic Landforms/Processes
  • EARTH SCIENCE > Solid Earth > Gravity/Gravitational Field
  • ngda
  • Geodetic Control
  • Geodetic/Global Positioning
Data Centers
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Platforms
  • GPS > Global Positioning System Satellites
  • NAVSTAR > NAVSTAR Global Positioning System
  • GLONASS > GLObalnaya NAvigatsionnaya Sputnikovaya Sistema
  • GNSS > Global Navigation Satellite System
Instruments
  • Earth Remote Sensing Instruments > Passive Remote Sensing > Positioning/Navigation > GPS
  • Earth Remote Sensing Instruments > Passive Remote Sensing > Positioning/Navigation > GPS > GPS Receivers
  • Earth Remote Sensing Instruments > Passive Remote Sensing > Positioning/Navigation > GPS > GNSS Receivers
Places
  • United States
Projects
  • NOAA > National Geodetic Survey (NGS) > Continuously Operating Reference Station (CORS)
Use Constraints No constraint information available
Fees
  • None
Source Datasets
  • NOAA archive: Continuously Operating Reference Stations (CORS)
    • National Geodectic Survey - Continuously Operating Reference Stations (CORS)
      Home page for CORS main facility in Silver Spring, MD. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • FTP access to NGS CORS in Silver Spring, MD (download)
      FTP site from CORS main facility in Silver Spring, MD. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • NGS CORS facility in Silver Spring, MD: User Friendly CORS utility (search)
      This utility allows users to obtain a specific block of Global Positioning System ( GPS ) data for a continuously operating reference station (CORS) contained in the network of GPS sites managed by the National Geodetic Survey. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • NGS CORS facility in Silver Spring, MD: Standard Download utility (search)
      CORS data search utility of daily files. Allows users to query by site id, state id, country id, data type or date. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • NGS CORS facility in Boulder, CO
      Home page for CORS alternate facility in Boulder, CO. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • FTP access to NGS CORS facility in Boulder, CO (download)
      FTP site from CORS alternate facility in Boulder, CO. Data is ingested in the at-sampling rate and available from NGS CORS online for 30 days. After 30 days, the CORS online data is decimated down to a 30-second sampling rate with the exception of the navigation files.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
    • CLASS website at http://www.class.ngdc.noaa.gov/saa/products/welcome
      NGS CORS data archived in CLASS infrastructure. Every effort is made to assure that archived data are at-sampling rate, where available.
    • Description of Source: Source Contribution: GNSS observational data in RINEX format and binary format, orbit data, and meteorological data (when available). Source Type: digital files via FTP
    • Temporal extent used:  1994-02-01  to  present
Lineage Statement GNSS observational data from the CORS network are ingested, translated, and processed by NGS and are posted to the NGS online servers as hourly or daily files, and ultimately retained as daily files in RINEX format. After 30 days, data in the at-sampling rate is copied to the NGDC archive, and NGS online holdings are then decimated to a 30-second sampling rate. Special use case: Certain groups such as the Federal Aviation Administration, the U.S. Coast Guard, NOAA's Earth System Research Laboratory (ESRL), and NGS, make GNSS data available in binary format to NGS. These data are used as input to algorithms for internal NOAA models such as the US-Total Electron Content product and to produce GPS Meteorology Water Vapor measurements. NGDC, not NGS, has decided to archive the raw data from these GPS stations as a daily tar file consisting of hourly binary files
Processor
  • DOC/NOAA/NOS/NGS > National Geodetic Survey, National Ocean Service, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NOS/NGS > National Geodetic Survey, National Ocean Service, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Processing Steps
  • INGEST: NGS has automated daily routines that harvests daily observational files in either binary or RINEX format at the original sampling rate, the daily broadcast ephemeris files, orbit files, and any corresponding meteorological files. For the special case use of FAA and USCG streaming data that are used as input to NOAA models, the streaming feed is harvested to a binary, incrementally-built hourly file.
  • PROCESSING: Data ingested by NGS are processed into RINEX format and made available online in either an hourly or daily cadence. Aside from positioning, processing includes the insertion of NGS headers, quality checks, and the production of quality control files (teqc summary files). Other scheduled routines retrieve higher level orbit files as they are made available.
  • DISTRIBUTION: NGS makes hourly and daily files available online. For the special case of binary FAA and USCG data, NGS pushes these files to NGDC every 5 minutes. NGDC stages the data for ESRL and SWPC groups, who harvests the data at a predetermined sub-hourly period. The completed binary hourly file at NGDC is kept locally. At the end of the day, a daily tar file consisting of the hourly data are created and staged for archive.
  • RETENTION: NGS retains the data at the original at-sampling rate for 30 days. After 30 days, NGS decimates its online holdings to a 30-second sampling rate.
  • ARCHIVE: Prior to the 30-day mark, the RINEX at-sampling rate data is copied to NGDC. Aftter 30 days, NGDC then stages, archives, and distributes the CORS data via the CLASS infrasturcture. For the special use case, the daily binary files from 4 days ago are archived by NGDC to CLASS.

Metadata Last Modified: 2014-06-20

For questions about the information on this page, please email: Francine.Coloma@noaa.gov