CRX is a Hatanaka compression for Rinex file used by many permanent networks. Y. Hatanaka of GSI wrote softwares for compress/uncompress, see

To use the software (example of CRX compression to uncompressed RNX format):

  • open a shell (e.g. Powershell)
  • go to the folder containing the executable
  • type “CRX2RNX.exe input.crx”
  • you get as output a RNX file that you can rename to .yyo
  • for help type “CRX2RNX.exe -h”