基于叠加扩频的无人机MIMO导频修正MLD抗干扰

针对无人机遥控链路常受干扰的影响导致性能下降甚至失锁,研究将多输入多输出(multiple input multiple output, MIMO)空时分组编码与直扩技术相结合实现对链路常见干扰抑制。提出叠加扩频的方法消除融合技术中存在的多址干扰、对抗窄带干扰并预防欺骗干扰;采用基于噪声子空间投影的简化最大似然译码(maximum likelihood decoding, MLD) 抑制自然以及强宽带噪声干扰,通过分析由信道估计误差引起的MLD扰动误差,并利用导频修正来降低信道估计误差对MLD性能影响。理论分析及仿真表明,该方案通信保密性好、鲁棒性强,能够实现对多种干扰的抑制,为未来无人机智能抗干扰的实现提供方案。

Anti-jamming scheme of pilot modification MLD based on superimposed spread spectrum for UAV-MIMO

The remote control link of unmanned aerial vehicle (UAV) is often cluttered by interference, which results in performance degradation or losing lock. The technologies of multiple input multiple output (MIMO) space time block codes and direct spread are combined to suppress the common interference in the remote control link. The superimposed spread spectrum is presented to eliminate multiple access interference in the fusion technology,combat against narrow-band jamming and avoid deception jamming. The maximum likelihood decoding (MLD) based on the subspace projection of noise is adopted to suppress the noise interference of natural and strong wideband. The disturb deviation of MLD caused by channel estimation deviation is analyzed. Then the pilot modification is set up to reduce the effect of channel estimate error on MLD performance. The theoretical analysis and system simulation show that the scheme has better communication privacy and great robustness which can suppress multi-population interferences. It can provide a scheme for achieving the intelligent anti-jamming of UAV in the future.