National Geospatial Data Asset (NGDA) Continuously Operating Reference Stations (CORS)
National Geodetic Survey (NGS)Data Set (DS) | ID: 39662 | Published / External
Item Identification
Title: | National Geospatial Data Asset (NGDA) Continuously Operating Reference Stations (CORS) |
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Short Name: | CORS |
Status: | Completed |
Publication Date: | 1994-04-21 |
Abstract: |
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 or GNSS 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 August 2018, the CORS network provides data from more than 2,000 active sites. CORS data holdings to include decommissioned stations, comes to a total of 2,718 sites. These sites are contributed by over 230 different organizations, and the network continues to expand. |
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 electron content (TEC) in the upper atmosphere. |
Notes: |
1295 |
Keywords
Theme Keywords
Thesaurus | Keyword |
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GCMD Instruments/Sensors Keywords | GPS : Global Positioning System |
GCMD Platform Keywords | GPS > Global Positioning System Satellites |
GCMD Platform Keywords | GROUND STATIONS |
GCMD Platform Keywords | GROUND-BASED OBSERVATIONS |
GCMD Platform Keywords | NAVSTAR > NAVSTAR Global Positioning System |
ISO 19115 Topic Category | geoscientificInformation |
ISO 19115 Topic Category | location |
NGDA Portfolio Themes | Geodetic Control Theme |
NGDA Portfolio Themes | National Geospatial Data Asset |
NGDA Portfolio Themes | NGDA |
NOS Data Explorer Topic Category | Geodetic/Global Positioning |
Physical Location
Organization: | National Geodetic Survey |
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City: | Silver Spring |
State/Province: | MD |
Data Set Information
Data Set Scope Code: | Data Set |
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Maintenance Frequency: | Continually |
Data Presentation Form: | Point data |
Entity Attribute Overview: |
The data includes daily GPS or GNSS observables along with computed geometric coordinates (Latitude, Longitude, Ellipsoid Height) for each station. |
Entity Attribute Detail Citation: |
Information on the details of the data sets is available at: https://www.ngs.noaa.gov/CORS/ |
Entity Attribute Detail URL: | https://geodesy.noaa.gov/CORS/ |
Distribution Liability: |
Use at your own risk |
Data Set Credit: | The CORS system benefits from a multipurpose cooperative endeavor involving NGS, many governmental, academic, commercial and private organizations who own and operate the bulk of the participating sites. |
Support Roles
Data Steward
Date Effective From: | 1994-04-21 |
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Date Effective To: | |
Contact (Organization): | NGS Communications and Outreach Branch |
Email Address: | ngs.infocenter@noaa.gov |
Phone: | (301) 713-3242 |
Fax: | (301) 713-4172 |
Distributor
Date Effective From: | 1994-04-21 |
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Date Effective To: | |
Contact (Organization): | NGS Communications and Outreach Branch |
Email Address: | ngs.infocenter@noaa.gov |
Phone: | (301) 713-3242 |
Fax: | (301) 713-4172 |
Contact Instructions: |
Email or call |
Metadata Contact
Date Effective From: | 1994-04-21 |
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Date Effective To: | |
Contact (Organization): | NGS Communications and Outreach Branch |
Email Address: | ngs.infocenter@noaa.gov |
Phone: | (301) 713-3242 |
Fax: | (301) 713-4172 |
Point of Contact
Date Effective From: | 1994-04-21 |
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Date Effective To: | |
Contact (Organization): | NGS Communications and Outreach Branch |
Email Address: | ngs.infocenter@noaa.gov |
Phone: | (301) 713-3242 |
Fax: | (301) 713-4172 |
Extents
Currentness Reference: | Ground Condition |
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Extent Group 1
Extent Group 1 / Geographic Area 1
W° Bound: | -180 | |
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E° Bound: | 180 | |
N° Bound: | 90 | |
S° Bound: | -90 |
Extent Group 1 / Time Frame 1
Time Frame Type: | Continuing |
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Start: | 1994-04-21 |
Spatial Information
Spatial Representation
Representations Used
Vector: | Yes |
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Reference Systems
Reference System 1
Coordinate Reference System |
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Reference System 2
Coordinate Reference System |
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Reference System 3
Coordinate Reference System |
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Reference System 4
Coordinate Reference System |
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Access Information
Security Class: | Unclassified |
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Data Access Policy: |
While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, 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. |
Data Access Procedure: |
https://www.ngs.noaa.gov/CORS/ https://geodesy.noaa.gov/CORS/ ftp://geodesy.noaa.gov/cors/ https://alt.ngs.noaa.gov/CORS ftp://alt.ngs.noaa.gov/cors/ https://geodesy.noaa.gov/UFCORS/ https://www.ngs.noaa.gov/CORS/standard1.shtml |
Data Access Constraints: |
None |
Data Use Constraints: |
While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, 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. |
Metadata Access Constraints: |
None |
Metadata Use Constraints: |
None |
Distribution Information
Distribution 1
Start Date: | 1994-04-21 |
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End Date: | Present |
Download URL: | https://geodesy.noaa.gov/CORS/data.shtml |
Distributor: | NGS Communications and Outreach Branch (1994-04-21 - Present) |
File Name: | CORS main data page |
Description: |
CORS main data page |
File Type: | Multiple formats |
Compression: | GZIP |
Review Status: | Chked MD |
URLs
URL 1
URL: | https://geodesy.noaa.gov/CORS/ |
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Name: | CORS Main page |
URL Type: |
Online Resource
|
Description: |
CORS Main page |
URL 2
URL: | ftp://geodesy.noaa.gov/cors/ |
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Name: | CORS FTP |
URL Type: |
Online Resource
|
Description: |
CORS FTP |
URL 3
URL: | https://alt.ngs.noaa.gov/CORS |
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Name: | CORS alternate Main page |
URL Type: |
Online Resource
|
Description: |
CORS alternate Main page |
URL 4
URL: | ftp://alt.ngs.noaa.gov/cors/ |
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Name: | Alternate CORS FTP page |
URL Type: |
Online Resource
|
Description: |
Alternate CORS FTP page |
URL 5
URL: | https://geodesy.noaa.gov/UFCORS/ |
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Name: | CORS UFCORS |
URL Type: |
Online Resource
|
Description: |
User-Friendly CORS data download page |
URL 6
URL: | https://geodesy.noaa.gov/CORS/standard1.shtml |
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Name: | CORS standard download |
URL Type: |
Online Resource
|
Description: |
CORS standard download |
URL 7
URL: | https://www.ngs.noaa.gov/CORS_Map/ |
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Name: | CORS Map |
URL Type: |
Browse Graphic
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Description: |
CORS interactive map |
Activity Log
Activity Log 1
Activity Date/Time: | 2017-02-27 |
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Description: |
Date that the source FGDC record was last modified. |
Activity Log 2
Activity Date/Time: | 2017-04-05 |
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Description: |
Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details. |
Activity Log 3
Activity Date/Time: | 2017-09-13 |
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Description: |
Partial upload of Spatial Info section only. |
Activity Log 4
Activity Date/Time: | 2018-02-08 |
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Description: |
Partial upload of Positional Accuracy fields only. |
Activity Log 5
Activity Date/Time: | 2018-08-08 |
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Activity Type: | Update |
Responsible Party: | Fran Coloma |
Description: |
Updates. Changing URL from HTTP to HTTPS, update lineage, add GPS as platform and instrument. |
Activity Log 6
Activity Date/Time: | 2019-10-24 |
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Activity Type: | Update |
Responsible Party: | Fran Coloma |
Description: |
Updates, removing special characters from Conceptual Consistency Attribute and specifics about the reference frame, as the convention is to use parentheses within notation. |
Technical Environment
Description: |
The GPS or GNSS data collected at these stations are made available to the public by NGS in Receiver INdependent EXchange (RINEX) format. The data include observation, meteorological (where available), navigation/ephemeris, station logs and NGS coordinate files for the stations. Most data are available within 1 hour from when they were recorded at the remote site, and the rest have a delay of 24 hours. |
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Data Quality
Representativeness: |
Receiver and Antenna is at least dual frequency, receiving L1 and L2 signals. Receiver tracks at least ten satellites above 0 degrees. Receiver provides L1 and L2 full wavelength carrier phase. Receiver must have be accepted as suitable for inclusion into International GNSS Service or IGS network Antenna code, antenna model + radome, must be permitted by NGS for inclusion into the CORS network. |
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Accuracy: |
The carrier phase observations are accurate to a few centimeters, once biases have been removed. For further information, see https://geodesy.noaa.gov/CORS//coords.shtml |
Horizontal Positional Accuracy: |
+/- 2.0 cm |
Vertical Positional Accuracy: |
+/- 4.0 cm |
Bias: |
The carrier phase observations are accurate to a few centimeters, once biases have been removed. For further information, see https://www.ngs.noaa.gov/CORS//coords.shtml |
Completeness Report: |
The National Geodetic Survey, or NGS, publishes coordinates for CORS in several reference frames. This includes the current global reference frame from the International GNSS Service, or 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/files/042011_CORS_Coordinate_Policy.pdf |
Conceptual Consistency: |
To become part of the NOAA CORS Network, each station must meet NGS' station criteria standards and maintain its integrity. See https://geodesy.noaa.gov/CORS/Establish_Operate_CORS.shtml document. Data is quality controlled by NGS before it is distributed to the public. In addition, NGS publishes position and velocity values for each CORS in both the global reference frame and in the National Spatial Reference System. More information about the NOAA CORS Network is available at: https://geodesy.noaa.gov/CORS/ |
Quality Control Procedures Employed: |
NGS defines thresholds during processing. |
Data Management
Have Resources for Management of these Data Been Identified?: | Yes |
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Approximate Percentage of Budget for these Data Devoted to Data Management: | Unknown |
Do these Data Comply with the Data Access Directive?: | Yes |
Is Access to the Data Limited Based on an Approved Waiver?: | No |
Approximate Delay Between Data Collection and Dissemination: | 30 days for RINEX |
If Delay is Longer than Latency of Automated Processing, Indicate Under What Authority Data Access is Delayed: |
NGS makes every effort to archive missing data. |
Actual or Planned Long-Term Data Archive Location: | NCEI-CO |
Approximate Delay Between Data Collection and Archiving: | 30 days for RINEX |
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?: |
NGS CORS dataset is ingested at two geographically separate and independent facilities, providing Continuity of OPerations (COOP). RINEX data is held and staged at the National Centers for Environmental Information (NCEI) for 30 days. NGS is allowed to make changes to that data holding at NCEI within the 30 day window. NCEI transfers data for archive to NOAA's Comprehensive Large Array-data Stewardship System (CLASS) after the 30 day period. NGS is the authority on the CORS data set, and can replace or remove archived files at its discretion. |
Lineage
Lineage Statement: |
CORS data is processed at an hourly or daily cadence, dependent a particular stations' retrieval frequency. Hourly data is deleted one day after daily file is created. |
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Process Steps
Process Step 1
Description: |
GPS or GNSS data that are received in either binary or Receiver INdepedent EXchange (RINEX) format, and are processed by NGS into a compressed daily RINEX formatted file. Other files made available include navigation/ephemeris, station logs, NGS coordinates and may include other observations, such as meteorological files. |
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Process Step 2
Description: |
RINEX data is posted online at the at-sampling rate for a period of 30 days, at both NGS CORS facilities. |
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Process Step 3
Description: |
At-sampling daily RINEX data is concurrently staged at NCEI for archive. |
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Process Step 4
Description: |
After 30 days, CORS at-sampling daily RINEX data (when available) is archived. |
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Process Step 5
Description: |
After 30 days, NGS online daily RINEX data are decimated to a 30-second sampling rate. |
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Acquisition Information
Instruments
Instrument 1
Identifier: | GPS (Global Positioning System) |
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Instrument / Gear: | Instrument |
Instrument Type: | GPS (Global Positioning System) |
Description: |
The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. This system consists of three segments: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments. |
Platforms
Platform 1
Identifier: | Global Positioning System (GPS) | ||
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Description: |
The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. This system consists of three segments: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments. |
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Mounted Instrument 1 |
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Catalog Details
Catalog Item ID: | 39662 |
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Metadata Record Created By: | Tyler Christensen |
Metadata Record Created: | 2017-04-05 13:06+0000 |
Metadata Record Last Modified By: | Fran Coloma |
Metadata Record Last Modified: | 2019-10-24 17:14+0000 |
Metadata Record Published: | 2019-10-24 |
Owner Org: | NGS |
Metadata Publication Status: | Published Externally |
Do Not Publish?: | N |
Metadata Next Review Date: | 2020-10-24 |