This paper deals with the GPS interference that was observed in the GPS receiver installed on KSLV-I. The interference on the launch site can be minimized in the third flight trial of KSLV-I to use another LNA with a filter improved out-of-band rejection performance. Based on the lesson learned from KSLV-I, the GNSS antenna for KSLV-II would be designed with strict out-of-band rejection characteristics.

Keywords: GPS, interference, KSLV-I, KSLV-II, antenna, LNA, filter