Archived RINEX files from both IGS stations and national GNSS CORS networks are now accessed by users via the Internet. All IGS data have been, and continue to be, available free-of-charge.
Although some GPS receiver network operators charge fees for their RINEX files,
the trend is to increasingly make such data available for free.
Note that no distinction is made between data sourced from an IGS station,
or from any other GPS receiver network.
Nevertheless it is sometimes useful to refer to a hierarchy of permanent GPS reference stations,