Welcome to the National Oceanic and Atmospheric Administration's (NOAA) Continuously Operating Reference Station (CORS) Network (NCN) https://geodesy.noaa.gov/CORS Last Updated: 12 October 2021 CONTENTS OF THIS FILE ====================== INTRODUCTION ACCESS TO DATA DIRECTORY STRUCTURE OF SITE BRIEF DESCRIPTION OF MAIN DIRECTORIES DETAILED DESCRIPTION OF THE CONTENTS OF THE DIRECTORY coord DETAILED DESCRIPTION OF THE CONTENTS OF THE DIRECTORY rinex FILE RETENTION POLICY USE CONSTRAINTS CONTACT INFORMATION INTRODUCTION ============ NOAA's National Geodetic Survey (NGS) operates the Continuously Operating Reference Station (CORS) network (NCN) that consists of group of Global Navigation Satellite System (GNSS) reference stations which provide code range and carrier phase data to users in support of postprocessing applications. The stations are owned and operated by federal, state, local agencies, private companies, and university groups, and NGS redistributes their data to the public free of charge. The 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, 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 a few sites have a delay of 24 hours. All data since 9 February (040) 1994 are available. ACCESS TO DATA ================= Data can be retrieved from https://geodesy.noaa.gov/corsdata/ Alternatively a customized data request service is available at: https://geodesy.noaa.gov/UFCORS DIRECTORY STRUCTURE OF SITE ================================= All characters within {} refer to variable names. For an explanation of these please see next section EXPLANATION OF DIRECTORY CONTENTS | | |--coord--|--coord_{yy}--|--{ssss} (individual sites) | | | |--Old--|{ssss}_{yy}.coord.txt.{yy}{Mmm}{dd} | | | | composite coordinate files | |--itrf2014_geo.comp.txt | |--itrf2014_xyz.comp.txt | |--itrf2014_geo.htdp.txt | |--itrf2014_xyz.htdp.txt | |--nad83_2011_geo.comp.txt | |--nad83_2011_xyz.comp.txt | |--nad83_2011_geo.htdp.txt | |--nad83_2011_xyz.htdp.txt | |--nad83_ma11_geo.comp.txt | |--nad83_ma11_xyz.comp.txt | |--nad83_ma11_geo.htdp.txt | |--nad83_ma11_xyz.htdp.txt | |--nad83_pa11_geo.comp.txt | |--nad83_pa11_xyz.comp.txt | |--nad83_pa11_geo.htdp.txt | |--nad83_pa11_xyz.htdp.txt | | |--Plots--|--{ssss}_14.short.png (short-term plots of daily positions) | | | |--Longterm--|--{ssss}_14.long.png (long-term plots of | | daily positions) | | |-- README.txt (This file) |-- RINEX211.txt (RINEX 2.11 definition file) | | | | | |--{ssssdddh}.{yyt}.gz | |--{yyyy}--|--{ddd}--|--{ssss}--|--{ssssdddh}.{yyt}.gz |--rinex --| |-{mmmdd}-| |--{ssssdddh}.{yy}S | | | | |--{ssssdddh}.{yy}m.gz --corsdata--| | | | Orbit files | |--brdc{ddd}0.{yy}n.gz | |--brdc{ddd}0.{yy}g.gz | |--igl{wwwwd}.sp3.gz | |--igs{wwwwd}.sp3.gz | |--igr{wwwwd}.sp3.gz | |--igu{wwwwd}_{hh}.sp3.gz | | | |--sum_gz--|--{ssssdddh}.{yy}S | | | |--{yyyy}.{ddd}.files.list (daily list of holdings) | | | | |--spec_prod--|--Various directories to support special products | | | |--station_log--|--{ssss}.log.txt | |--cumulative.station.info.cors | | | | | |--beta--|--test subdirectories (not for general use) | | | BRIEF DESCRIPTION OF MAIN DIRECTORIES ================================== coord NAD 83, ITRF, and IGS coordinates and velocities for each CORS site (see next section for a description of the files and their formats) Plots Short-term timeseries plots of CORS sites. These files show the difference between the calculated daily position and the published coordinate listed in the coord file for the previous few months. Long-term timeseries plots derived from our "multiyear"/MYCS2 project. Last updated April 2017. rinex RINEX data files, orbit files (see next section for a description of the files and their formats) station_log Station information, including current and historical equipment used at a site. File format {ssss}.log.txt Where ssss - 4-character site id spec_prod Special products not for operational use beta Test data, not for operational use DETAILED DESCRIPTION OF THE CONTENTS OF THE DIRECTORY coord ========================================= For detailed explanation of the files contained in this directory and their formats see: https://geodesy.noaa.gov/corsdata/coord/ in /corsdata/coord the following directories and files are available Directories: coord_{yy} where yy is a 2-digit year that corresponds to a particular Global reference frame. Currently, effective 4 September 2019, NGS supports ITRF14 which is located in coord_14, prior to this NGS supported global frames in the International GNSS Service (IGS) Frame e.g. in coord_08 any IGS coordinates are in IGS08. Within each directory up to 6 types of files are present: In the directory coord_14 {ssss}_14.coord.txt - is the coordinate file that contains the current ITRF2014 and NAD 83(2011,MA11,PA11) xyz and geographic coordinates for a particular site Old/{ssss}_14.coord.txt.{yy}{Mmm}{dd} - are older coordinate file that applies to the time prior to the specified data ({yy}{Mmm}{dd}) ssss - 4-character id yy - 2-digit year Mmm - 3-letter month dd - 2-digit day of month The following files contain composite listings of all coordinates for CORS, including decommissioned sites. itrf2014_geo_comp.txt - coordinates are computed ITRF2014 geographic coordinates itrf2014_geo_htdp.txt - coordinates are modeled ITRF2014 geographic coordinates itrf2014_xyz.comp.txt - coordinates are computed ITRF2014 xyz coordinates itrf2014_xyz.htdp.txt - coordinates are modeled ITRF2014 xyz coordinates nad83_2011_geo.comp.txt - coordinates are NAD_83(2011) computed geographic coordinates nad83_2011_geo.htdp.txt - coordinates are NAD_83(2011) modeled geographic coordinates nad83_2011_xyz.comp.txt - coordinates are NAD_83(2011) computed xyz coordinates nad83_2011_xyz.htdp.txt - coordinates are NAD_83(2011) modeled xyz coordinates nad83_ma11_geo.comp.txt - coordinates are NAD_83(MA11) computed geographic coordinates nad83_ma11_geo.htdp.txt - coordinates are NAD_83(MA11) modeled geographic coordinates nad83_ma11_xyz.comp.txt - coordinates are NAD_83(MA11) computed xyz coordinates nad83_ma11_xyz.htdp.txt - coordinates are NAD_83(MA11) modeled xyz coordinates nad83_pa11_geo.comp.txt - coordinates are NAD_83(PA11) computed geographic coordinates nad83_pa11_geo.htdp.txt - coordinates are NAD_83(PA11) modeled geographic coordinates nad83_pa11_xyz.comp.txt - coordinates are NAD_83(PA11) computed xyz coordinates nad83_pa11_xyz.htdp.txt - coordinates are NAD_83(PA11) modeled xyz coordinates In the directories coord_08 (No longer regularly maintained as of 4 September 2019) see files as described similar to above scription for coord_14, but referenced to IGS08 In addition, short-term plots in IGS08 and long-term plots (MYCS1) are available, but were frozen as of 4 September 2019, in the sub-directory plots_08 and plots_08/Longterm (long-term plots) DETAILED DESCRIPTION OF THE CONTENTS OF THE DIRECTORY rinex ========================================= in /corsdata/rinex/yyyy/ddd the following orbit/ephemeris files are available this is the same as: /corsdata/rinex/yyyy/mmmdd Global broadcast orbit: brdc{ddd}0.{yy}n.gz - GPS global broadcast/navigation/ephemeris file gzip compressed brdc{ddd}0.{yy}g.gz - GLONASS global broadcast/navigation/ephemeris file gzip compressed ddd - is 3-digit day-of-year yy - is 2-digit year These files are built cumulatively every hour till the end of the day High-precision orbits published by IGS: For detailed information on IGS orbit products see https://igs.org/products/ wwww - is the 4-digit GPS week d - is the 1-digit GPS day 0-Sunday,...6-Saturday hh - is the 2-digit hour 00,06,12,18 IGS ultrarapid orbits are produced every 6 hours igu{wwww}{d}_{hh}.sp3.gz - IGS ultrarapid GPS orbits in sp3c format gzip compressed IGS rapid orbits are produced with a latency of approximately 18 hours igr{wwww}{d}.sp3.gz - IGS rapid GPS orbits in sp3c format gzip compressed IGS precise/final orbits are produced with a 14-16 day latency igs{wwww}{d}.sp3.gz - IGS final GPS orbits in sp3c format gzip compressed igl{wwww}{d}.sp3.gz - IGS final GLONASS orbits in sp3c format gzip compressed Please note: From 1994.002-2020.138 the IGS final orbits have been updated to IGS repro2 solutions and are aligned to IGS14 From 2020:139-present the IGS final orbits are aligned to IGb14 {yyyy}.{ddd}.files.list - a list of daily RINEX observable files with corresponding timestamp and size in bytes in /corsdata/rinex/yyyy/hold_sum 1 or 2 directories are present ddz - always present dgz - only present for the current year In each of these directories is a single file for each day that contains a modified SUM line from the teqc summary files (see next section). Each file has the following name summary.{yyyy}.{ddd}.fileinfo yyyy - is a 4-digit year ddd - is a 3-digit day-of-year Each file contains the following columns obs typ SSSS first epoch last epoch St-En dt #expt #exp #actu e/a e/a multi Obs per Tot Group/ File yyyy-ddd hh:mm yyyy-ddd hh:mm hrs sec 24obs obs obs 24% % mp1 mp2 slip Slps Agency Time Stamp obs - Observable type: gp - GPS only; gn - GPS + GLONASS typ - Type of compression: dz - daily Hatanaka and UNIX compressed; gz - gzip compressed SSSS - 4-alphanumeric site identifier first epoch - Date and time of first epoch of data contained in the file last epoch - Date and time of last epoch of data contained in the file St-En - Number of hours of data contained in the file excludes data gaps dt - Sampling rate of file in seconds #expt 24obs - Expected number of observations that could be collected with a cutoff angle of 5 degrees over a 24hr period #act obs - Actual number of observations that were collected with a cutoff angle of 5 degrees e/a 24% - Percentage of actual number of observations compared to expected number of observation (see two previous columns) e/a % - Percentage of actual number of observations compared to expected number of observation given actual start and end time, but no data gaps multi - Pseudorange MP1 and MP2 multipath Obs per slip - Number of observation collected before a cycle slip is detected Tot Slps - Total number of cycle slips detected in the file Group/Agency - NGS internal 1-6 alphanumeric code representing Group/Agency contributing data for the site. File Time Stamp - Time stamp in UTC when the teqc summary file (see next section) was created in /corsdata/rinex/{yyyy}/{ddd}/{ssss} 1 or more of the following data files are available this is the same as: /corsdata/rinex/{yyyy}/{mmmdd}/{ssss} {ssss}{ddd}{h}.{yy}{t}.{C} ssss - is the 4-character site identifier ddd - is a 3-digit day-of-year h - for 1 hour long (60 minute duration) files this is a letter a through x that corresponds to the start hour as shown below 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 a b c d e f g h i j k l m n o p q r s t u v w x for 24 hour (daily) long files the number 0 (zero) is used yy - is a 2-digit year t - is the type of file. 6 types exist d - is a RINEX observation file that has been decimated to a sampling rate of 30 seconds and that is Hatanaka compressed Hatanaka uncompress software is available at: https://terras.gsi.go.jp/ja/crx2rnx.html g - is a RINEX GLONASS navigation data file m - is a RINEX meteorological data file n - is a RINEX GPS navigation data file o - is a RINEX observation file with the receiver sampling rate of 1, 5, 15, 30 seconds, after 30 days this file is decimated to 30 seconds S - is a summary file of the Hatanaka compressed file (type d.Z) created using the TEQC software C - is compression type gz - gzip compression format RINEX data may contain the following observation types 2007-250-present can contain: GPS L1+L2+L2C+L5, GLONASS L1+L2 Prior to 2007-250 contain only GPS L1+L2 in /corsdata/rinex/{yyyy}/{ddd}/sum_gz the summary files are the same as /corsdata/rinex/{yyyy}/{mmmdd}/{sum_gz} {ssss}{ddd}{h}.{yy}S This is a summary file of the file (type o.gz) created using the TEQC software FILE RETENTION POLICY ====================== RINEX observation, meteorological, navigation and TEQC summary files: Hourly files are only kept for 2 days Daily files are kept permanently However after 30 days the 24hr (daily) RINEX observation files that are gzipped ({ssss}{ddd}0.{yy}o.gz) are decimated to a 30 second sampling rate equivalent to the {ssss}{ddd}0.{yy}d.gz Meteorological files are available only for sites with independent meteorological sensors After six-months to one year the second copy of the RINEX observation files that are gzipped is removed i.e. file name {ssss}{ddd}0.{yy}o.gz All orbit files are kept permanently Coord files are updated as needed Logs files are updated as needed Plot files are updated daily 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. Use at your own risk. CONTACT INFORMATION ================================== If you have questions about this file or about CORS in general please check https://geodesy.noaa.gov/CORS or email ngs.cors @ noaa.gov