Short Citation:
National Geodetic Survey, 2021: National Geospatial Data Asset (NGDA) Continuously Operating Reference Stations (CORS), https://www.fisheries.noaa.gov/inport/item/39662.

Item Identification

Title: National Geospatial Data Asset (NGDA) Continuously Operating Reference Stations (CORS)
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
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
City: Silver Spring
State/Province: MD

Data Set Information

Data Set Scope Code: Data Set
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

CC ID: 478492
Date Effective From: 1994-04-21
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

CC ID: 478494
Date Effective From: 1994-04-21
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

CC ID: 478495
Date Effective From: 1994-04-21
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

CC ID: 478493
Date Effective From: 1994-04-21
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

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 478498
W° Bound: -180
E° Bound: 180
N° Bound: 90
S° Bound: -90

Extent Group 1 / Time Frame 1

CC ID: 478497
Time Frame Type: Continuing
Start: 1994-04-21

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Reference Systems

Reference System 1

CC ID: 885049

Coordinate Reference System

CRS Type: Geographic 3D
EPSG Code: EPSG:6319
EPSG Name: NAD83(2011)
See Full Coordinate Reference System Information

Reference System 2

CC ID: 885050

Coordinate Reference System

CRS Type: Geographic 3D
EPSG Code: EPSG:6321
EPSG Name: NAD83(PA11)
See Full Coordinate Reference System Information

Reference System 3

CC ID: 885051

Coordinate Reference System

CRS Type: Geographic 2D
EPSG Code: EPSG:6322
EPSG Name: NAD83(PA11)
See Full Coordinate Reference System Information

Reference System 4

CC ID: 885052

Coordinate Reference System

CRS Type: Geographic 2D
EPSG Code: EPSG:6325
EPSG Name: NAD83(MA11)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
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

CC ID: 767388
Start Date: 1994-04-21
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

CC ID: 478485
URL: https://geodesy.noaa.gov/CORS/
Name: CORS Main page
URL Type:
Online Resource
Description:

CORS Main page

URL 2

CC ID: 478486
URL: ftp://geodesy.noaa.gov/cors/
Name: CORS FTP
URL Type:
Online Resource
Description:

CORS FTP

URL 3

CC ID: 478487
URL: https://alt.ngs.noaa.gov/CORS
Name: CORS alternate Main page
URL Type:
Online Resource
Description:

CORS alternate Main page

URL 4

CC ID: 478488
URL: ftp://alt.ngs.noaa.gov/cors/
Name: Alternate CORS FTP page
URL Type:
Online Resource
Description:

Alternate CORS FTP page

URL 5

CC ID: 478489
URL: https://geodesy.noaa.gov/UFCORS/
Name: CORS UFCORS
URL Type:
Online Resource
Description:

User-Friendly CORS data download page

URL 6

CC ID: 478490
URL: https://geodesy.noaa.gov/CORS/standard1.shtml
Name: CORS standard download
URL Type:
Online Resource
Description:

CORS standard download

URL 7

CC ID: 885053
URL: https://www.ngs.noaa.gov/CORS_Map/
Name: CORS Map
URL Type:
Browse Graphic
Description:

CORS interactive map

Activity Log

Activity Log 1

CC ID: 478529
Activity Date/Time: 2017-02-27
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 478528
Activity Date/Time: 2017-04-05
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

CC ID: 586706
Activity Date/Time: 2017-09-13
Description:

Partial upload of Spatial Info section only.

Activity Log 4

CC ID: 716829
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 5

CC ID: 767378
Activity Date/Time: 2018-08-08
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

CC ID: 885048
Activity Date/Time: 2019-10-24
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.

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.

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
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.

Process Steps

Process Step 1

CC ID: 478483
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.

Process Step 2

CC ID: 767383
Description:

RINEX data is posted online at the at-sampling rate for a period of 30 days, at both NGS CORS facilities.

Process Step 3

CC ID: 767384
Description:

At-sampling daily RINEX data is concurrently staged at NCEI for archive.

Process Step 4

CC ID: 767385
Description:

After 30 days, CORS at-sampling daily RINEX data (when available) is archived.

Process Step 5

CC ID: 767386
Description:

After 30 days, NGS online daily RINEX data are decimated to a 30-second sampling rate.

Acquisition Information

Instruments

Instrument 1

CC ID: 767380
Identifier: GPS (Global Positioning System)
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

CC ID: 767381
Identifier: Global Positioning System (GPS)
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.

Mounted Instrument 1

Identifier: GPS (Global Positioning System)

Catalog Details

Catalog Item ID: 39662
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