A Multi-Polarization Interference Suppression Strategy of GNSS Antenna Array Based on Polarization Equalization

As the intricacy of electromagnetic environments escalates, multi-polarization interference has emerged as a significant challenge in global navigation satellite systems (GNSS) countermeasures. Nevertheless, a definitive methodology for alleviating this interference has yet to be established. In response, this article firstly formulates a receiving model for GNSS antenna arrays that addresses multi-polarization interference, along with a corresponding suppression analysis model. The findings indicate that it consumes two degrees of freedom (DOFs), with both antenna gain and antenna polarization ratio identified as critical determinants. Subsequently, to mitigate this, a modulo-digital two-stage weighted anti-interference strategy based on polarization equalization is proposed. The strategy involves the integration of analog amplitude modulators and phase shifters positioned after the orthogonal feed points of the antennas, thereby constructing an analog polarization weight vector, which not only reduces the costs associated with radio frequency (RF) channels but also facilitates the flexible adjustment of polarization characteristics. Furthermore, an optimization objective in terms of the antenna polarization ratio disruption norm (APRDN) is articulated, and the augmented Lagrangian multiplier (ALM) method is employed to derive the analog polarization weight vector while minimizing the APRDN. Finally, the validity of the models and the effectiveness of the proposed strategy are corroborated through both empirical tests and simulations. Notably, when the direction of arrival (DOA) range of multi-polarization interference is confined to less than 6° in azimuth and elevation, the overall enhancement in suppression performance exceeds 20 dB.