Performance Estimates of GNSS Receiver Jamming with Adaptive Nulling Technique

A Power Inversion adaptive algorithm (PI) is often used to get the nulling beamform in GNSS jamming techniques. When the signal to interference ratio is 80 dB, a PI algorithm can accurately identify the direction of jamming at high resolution. However, a large ribbon nulling will form around the direction of the RF interference signal in the algorithm. If the signal to interference ratio reduces to 20 dB, the resolution of the interference signal will seriously deteriorate. The multiple signal classification (MUSIC) algorithm has super-resolution features; it can achieve power minimization through the signal subspace and noise subspace orthogonal principles. A two-dimensional spectral peak search technology is used in searching the azimuth and elevation of interference to accurately estimate the DOA and effectively distinguish the desired signal and the interference signal. When the signal to interference ratio is high, the suppression depth from the MUSIC-PI algorithm is significantly better than the traditional power inversion algorithm. In a low signal-to-interference ratio condition, the MUSIC-PI algorithm is still valid when suppressing the interference in the right direction, but the power inversion algorithm cannot discriminate the direction of interference accurately. Computer simulation results show the effective and robust performance of the MUSIC algorithm in the GNSS jamming field.