Data Download

Data Download

The account you create by registering for the CHAIN website also creates a Level 1 FTP account at ftp://chain.physics.unb.ca/ for access to both CHAIN GPS and CADI data.

Level 1 accounts provide FTP access to the following data products:

    GPS Data
  • Daily 30-second RINEX Observation file
    CADI Data
  • .md1 and .md2 files

In addition, Level 2 FTP accounts also provide access to the raw Novatel GPS receiver data which includes the 50Hz data. An upgrade to a level 2 account can be requested by email to This email address is being protected from spambots. You need JavaScript enabled to view it..

All data is stored in a compressed format. Software to uncompress these files can be found at http://www.gzip.org/.

GPS Data

The Daily 30-second RINEX observation files are archived below ftp://chain.physics.unb.ca/gps/data/daily/ in subdirectories by day according to the following template: ftp://chain.physics.unb.ca/gps/data/daily/YYYY/DDD/YYo/ where YYYY is the four-digit year, DDD is the three-digit day of year, and YY is the 2-digit year Within each subdirectory there will be one RINEX file per station.

The raw GPS receiver (.nvd) files are archived below ftp://chain.physics.unb.ca/gps/data/nvd/ in subdirectories by month according to the following template: ftp://chain.physics.unb.ca/gps/data/nvd/STN/YYYY/MM/. Within each subdirectory there will be one nvd file per hour for each day of the month. The nvd files are named according to YYMMDD_HHMMSS.nvd.gz where YY is the 2-digit year, MM is the 2-digit month, DD is the 2-digit day of month, HH is the 2-digit hour. MM and SS which represent the minutes and seconds are typically 00 and 00 except in the infrequent case when the receiver is restarted.

CADI Data

The md1 and md2 CADI files are archived below ftp://chain.physics.unb.ca/cadi/ in subdirectories by day according to the following template: ftp://chain.physics.unb.ca/cadi/ST/YYYY/YYMMDDST/ where ST is the 2-letter station abbreviation, YYYY is the four-digit year, YY is the 2-digit year, MM is the 2-digit month, and DD is the 2-digit day of month