跳/扩频测控信号自适应波束形成方法

为解决跳/扩频测控中阵列天线设计所面临的信号频带宽、空域范围广、干扰强度大等问题,将线性约束法与二阶锥规划方法相结合,得到能够同时满足频率不变、方向不变的波束形成算法.利用二阶锥规划将波束形成器的设计转化为给定频率响应的FIR滤波器设计,针对用于宽带波束形成的FIR滤波器的非线性相位特点,采用最小均方误差准则,使所设计FIR滤波器的频率响应逼近于期望滤波器.通过增加约束条件,使不同空间指向的主瓣宽度基本保持不变,并在干扰方向形成宽零陷来有效抑制宽带干扰.仿真计算表明,在跳/扩频信号的工作频带内,波束方向图能够保持很好的频率不变特性,且在±60°范围内波束方向图的主瓣束宽、增益、零陷与参考波束基本保持一致,能够更好地满足航天测控任务对阵列天线的需求.

Adaptive Beamforming Algorithm forDS/FH Spread Spectrum TT and C Signals

In order to solve the existing problems of antenna in DS/FH spread spectrum TT and C system such as wideband spectrum, wide range of airspace, and strong interference, a novel method was proposed to obtain a steering invariant and frequency invariant beampattern by combining the second order cone programming (SOCP) constraints with linear constraints. Taking the advantages of SOCP, the beamformer design problem was converted into a FIR filter design problem with a given frequency response. For the non-linear phase characteristics of the FIR filter used for the broadband beamformer, the frequency response of the designed filter was made to approximate to the frequency response of desired filter by using the least squares error criterion. By adding the constraint condition, the algorithm was made to maintain a steering-invariant beampattern in different orientation with the broad null to reject broadband interferences. Simulation results show that the proposed algorithm can make the beampattern response approximately the same to the DS/FH signals at different frequencies, and realize constant beamwidth, gain, and adaptive null control under the designed main lobe direction of ±60°, which can better meet the requirement of array antenna for aerospace TT and C system much. Key words：