采用宽带信号的相控阵雷达可获得高的距离分辨率,但也面临挑战:宽带数字波束合成和自适应抗干扰。典型的宽带自适应数字波束合成架构中,首先,在基带采用分数延时滤波器实现多通道的延时补偿;然后,将宽带信号分解为许多子带,在每个子带内做传统的窄带自适应数字波束合成;最后,合成为宽带波束输出。该信号处理方法,在宽带条件下,通过宽带延时补偿实现了精确的波束指向,取得了较好的抗干扰性能。文中基于子带化方法,提出了一种新的架构,将延时补偿合并到窄带波束合成中,即用窄带的附加相移,代替了原有的多通道延时补偿单元。结果是该架构中不再需要分数延时滤波器,大大降低了计算量节约硬件资源。同时,仍然保证了宽带阵列雷达波束的精确指向。结合相控阵雷达阵列实例,文中分别采用传统架构及所提出的新架构完成宽带波束合成,给出仿真结果以供对比,证明了新架构的有效性。

For modern phased array radar, wideband system has been developed for the benefits of fine resolution. However, it introduces two main challenges, wideband digital beamforming and wideband adaptive digital beamforming for jamming cancellation. A typical architecture of wideband adaptive digital beamforming consists of time delay compensation using fractional delay filter at base-band followed by subband decomposition and narrowband adaptive digital beamforming. This processing scheme has achieved precise beam steering and good jamming cancellation performance over wideband. In this paper, a novel architecture is proposed by incorporating time delay compensation at digital beamforming in each subband. Without wideband time delay compensation explicitly, different steering vector is applied instead in different subband accordingly, in order to maintain the beam steering accuracy. Additionally, the computation burden is significantly reduced by eliminating the fractional delay filters. Simulation of the typical and novel processing schemes are carried out for comparison. The numerical results show that the novel method can achieve as good performance as the typical method at lower expense of computational throughput, which validates the efficiency of the proposed architecture.

TN957.51

国家自然科学基金资助项目(61571294);航空科学基金资助项目(2015ZD07006)