In most GNSS data repositories, GNSS observation data files are stored by GNSS station/day in the Hatanaka-compressed Receiver INdependent EXchange (RINEX).
The Hatanaka-compressed format [Hatanaka, Y. (2008): A Compression Format and Tools for GNSS Observation Data, Bulletin of the Geographical Survey Institute, 55, 21-30] is used to reduce the file size of the RINEX data files to a minimum.
The Hatanaka-compressed format is a two-step compression format with one of the steps being the common compression gzip or compress (for older files). Once downloaded, Hatanaka-compressed RINEX files can be decompressed using the RNXCMP software, which performs both decompression steps and outputs the GNSS data file in the RINEX format. Example of the Hatanaka-compressed RINEX file naming convention for the daily GNSS data of the station GENO00ITA for Day Of Year (DOY) 020 of the year 2023:- GENO020.23D.Z (for RINEX 2 data)
- GENO00ITA_R_20230200000_01D_30S_MO.crx.gz (for RINEX 3 data)