天波雷达后多普勒自适应波束形成

Post-Doppler Adaptive Digital Beamforming of Skywave Radar

该文推导了短波干扰在距离-多普勒域上的解析表达式,表现为平行于距离轴的恒幅谱脊;分析了电离层运动导致的短波干扰空间非平稳性,其等效为各阵元上相同多普勒频点之间的幅相误差,对自适应波束形成的影响可以忽略。在上述分析的基础上,该文提出了天波雷达后多普勒自适应波束形成方法,首先将各阵元接收信号变换到距离-多普勒域上,然后在各个频点上分别进行自适应处理。实测数据处理表明该方法的干扰抑制性能良好,稳健性也较强。

The analytical expression of shortwave interference in the range-Doppler domain is derived and is found to exhibit a constant-amplitude spectrum ridge parallel to the range axis. The spatial nonstationarity of the shortwave interference induced by ionosphere perturbation is then analyzed and is found to be equivalent to the amplitude-phase error between the same frequency points of shortwave interference on different antenna elements; hence, the above mentioned spatial aonstationarity only a has a slight effect on the performance of Adaptive Digital BeamForming （ADBF）. On the basis of the above analyses, this paper presents a post-Doppler ADBF approach for skywave radar. This approach involves transforming the received signal in each antenna element into a range-Doppler domain and then performing adaptive processing at each Doppler frequency point. The real radar data processing conducted in this study shows that the ADBF approach has a good interference suppression performance and strong robustness.