2D Notch Generator Algorithm for GNSS Space–time Anti-Jamming Based on Frequency-Invariant-shaped Beampattern Synthesis

This paper proposes a 2D notch generator algorithm based on frequency-invariant (FI)-shaped beampattern synthesis for the Global Navigation Satellite System (GNSS) space–time anti-jamming blind null-steering mode. Unlike conventional blind null-steering anti-jamming algorithms based on the power inversion (PI) algorithm, the developed method treats the blind null-steering spatial filter as a 2D spatial notch filter. The beampattern synthesis method is used to solve the value of the space–time filter. With the jamming direction as prior information, constraints are applied to the flat-top (FT) and nulling (NL) regions, and FI-shaped constraints are added to the FT region to establish the objective function. NL and FI enhancement coefficients are introduced to ensure the convergence speed of the objective function and the depth of nulling. The optimization method based on the alternating direction multiplier method is employed to solve the objective function. This synthesis method is applicable to arbitrary antenna arrays. The simulation shows that compared with the PI-based algorithms, the proposed algorithm ensures undistorted reception of GNSS signals, considerably improves the receiver’s signal-to-jamming-noise ratio in different jamming scenes, enhances anti-jamming ability, and achieves an improvement of better than 20 dB in multiple three-jamming scenes.