Global Navigation Satellite System (GNSS) receiver can get relatively accurate navigation information all around the world, so that GNSS receiver is widely used for military purpose such as pinpoint strike or command and control. On the other hand, when GNSS receiver is jammed, GNSS receiver easily loses the satellite signal. To overcome jamming signal in the wartime situation, anti-jamming GNSS receiver is developed. Even though anti-jamming function is normally operating, GNSS navigation error increase when Jamming to Noise Ratio (JNR) exceed a limit level, so that users had better not use the GNSS signal. In this paper, we checked a normal operation limit of anti-jamming GNSS receiver when jamming that surpass the anti-jamming capability and proposed a method to make the Navigation System (INS) discard inaccurate navigation information obtained from GNSS receiver under jamming environment. We demonstrated not only a method for quick recovery from navigation error when jamming is cleared out but also the testing method and results when implemented on the GNSS receiver.

Keywords: GNSS receiver, anti-jamming, jammer to noise ratio