For consistency within SimGEN/PosApp Spirent has decided to use the GPS nomenclature for GLONASS terms that are common to both systems. In this case the following holds true:
GLONASS RINEX term GUI parameter
TauN^ = Af0 (Zero Order clock correction term)
GammaN = Af1 (First Order clock correction term)
TauC^ = A0 (GLONASS system time offset)