Global Navigation Satellite System (GNSS) is used in a variety of fields such as aviation, ocean, cars and dependence of GNSS is increasing in our life. However, As dependence of GNSS is increasing, GNSS’s vulnerabilities are appeared. One of them is GNSS Jamming. Damages of GNSS Jamming were occurred in foreign countries and Korea was also damaged by North Korean activities of GNSS Jamming. There are many studies including estimation of jamming signal’s DOA(Direction of Arrival) for counteracting from intended jamming. The methods for estimating jamming signal’s DOA are largely classified two ways. One is Spectral Estimation. The other is Parametric Estimation. In this paper, We calculated Tracking Threshold power to unlock L1 signal (C/A Code) and analyzed estimation possibility of DOA of CW Jamming signal having more than Tracking Threshold power using Conventional Beamforming (Bartlett Method) and Minimum Variance Distortionless Responses (MVDR) algorithms under the Beamforming/Nulling methods.

Keywords: adaptive array, DOA, beamforming/nulling, MVDR