There are two types of IGC recording devices available, their use depending on the type of flight performance to be claimed:
A device for recording the position and altitude of the glider using GNSS satellite data and barometric pressure for which an IDC-approval document has been issued by the GNSS FR Approval Committee (GFAC). There are three levels of approval listed in para 1.4.1 of Annex B to the Sporting Code for Gliding (SC3B):
A GPS recorder unit (not as secure as a IGC-approved flight recorder) which may be used for evidence for silver and gold flights only, under rules given in the Appendix to Chapter 4 of the Sporting Code for Gliding (SC3) and amplified in Annix C to this Code (SC3C).
The following pages give more details of these devices, with links to rules and approval documents.