Data Format

The GPS observation files are available to users in the format RINEX (Receiver INdependant EXchange), which is a standard exchange format and can be used by most processing software. The file name syntax is in the form alexdddf.yyt and adheres to the following rules :

alex, 4-character station name designation,

ddd, day of the year,

f, file sequence number within day (0 contains all the existing data of the currrent day or a,b...,x for hourly files),

yy, year,

t, file type (o for observation file, e for a compressed observation file).


RINEX files are compressed by Hatanaka programmes.


Downloading the files

The files can be downloaded through an FTP (File Transfer Protocol) address

and are spread amongst 3 different folders.

data_1: 1 hour files at 1 second recording rate,

data_15: 24 hour files at 15 second recording rate,

data_30: 24 hour files at 30 second recording rate.


Expanding the files

Expanding programmes can be downloaded at :

To expand RINEX files, download the expanding software into a designated folder and then copy the RINEX files to be expanded into the same folder.

In an MSDOS window, type the command crz2rnx1 followed by the name of the compressed RINEX file (in the form alexdddf.yye) to obtain the expanded RINEX file (in the form alexdddf.yyo).

The RINEX file thus obtained can be used by a GPS processing software.

Example: By typing the command crz2rnx1 alex124a.01e, one obtains the file alex124a.01o.




latest update: 26/06/2006