基于SD-LCMV算法的FDA平台外干扰抑制

针对频率分集阵列（FDA）接收机在抑制与目标位置接近的平台外干扰过程中，最小方差无失真响应（MVDR）波束形成器在阵元数较大、导向矢量失配情况下出现的主瓣畸变问题展开分析。在采用重叠正弦频率分集阵列接收结构代替一维均匀线性频率分集阵列（ULA-FDA）接收的基础上，通过可变加载约束的最速下降线性约束最小方差（SD-LCMV）准则求解导向矢量失配时的权矢量，实现对阵列方向图主瓣的有效纠偏和保形。仿真验证了采用正弦频控函数的重叠子阵FDA阵列具有最佳的主瓣宽度和低旁瓣特性。当存在2°的指向误差时，正弦频控函数的重叠子阵FDA阵列经导向矢量修正得到的阵列方向图在有效抑制干扰的同时能够实现主瓣的纠偏和保形。 

FDA platform external interference suppression based on SD-LCMV algorithm

In the process of suppressing the interference which is close to the target position, minimum variance distortionless response (MVDR) beamformer will have the mainlobe distortion problem with mismatched steering vector or larger number of elements. We use the overlapping subarray-based sin-FDA as the receiving array instead of the uniform linear array frequency diverse array (ULA-FDA). The weighted vector of the mismatched steering vector is solved by the steepest descent linear constrained minimum variance (SD-LCMV) algorithm, which can effectively correct and preserve the mainlobe of the beampattern. Simulation verifies that the overlapping subarray-based sin-FDA has the best mainlobe width and low sidelobe characteristics. When there is a pointing error of 2°, the steering vecter of the overlapping subarray-based sin-FDA can be corrected and the shape of the mainlobe can be corrected while effectively suppressing the interference.