GNSS Digitized IF Signal Simulator (GDISS) is being developed by ETRI as a part of development of software- based Test & Evaluation Facility which will provide test and evaluation environment for various software level application and navigation algorithm in GNSS. GDISS will provide digitized IF data of GPS and Galileo signals. In this paper, GDISS prototype for L1, L2C, and E1(B&C) is developed and verified. The proposed prototype has good modularity and flexibility to add conveniently various modelings like ionospheric model, tropospheric model, multipath model, satellite clock model, etc. It will be verified by the commercial S/W receiver, Nordnav, and the S/W receiver implemented by CNU(Chungnam National University).