调零天线中的空域极化域联合抗干扰算法

在期望信号功率较小情况下，强同频干扰容易造成系统灵敏度下降，比如卫星导航和卫星通信。采用一个4阵元正交极化阵列，可以通过空域和极化域联合方式对干扰进行抑制。阵列参考阵元位于圆心，其余3个阵元均匀分布在圆周上。自适应滤波采用功率倒置准则下的 LMS算法，该方法调整每个正交极化阵元权系数，使得阵列在干扰极化下等效的极化匹配因子接近为0，实现干扰抑制。算法无需信号空间信息，实现简单，同时使阵列自由度达到6，从而增加抗干扰个数。计算机仿真证明了4个阵元阵列可以有效抑制最多6个干扰，而且，通过极化域处理，即使干扰信号与期望信号入射角度相同，只要极化不同，也可以抑制干扰而保持对期望信号增益。

The new anti-jam algorithm for nulling antenna in space and polarization domains

The sensitivity of the receiver is easy to be degraded by enemy co-channel interferences if the desired signal is weak,such as satellite navigation or communication system.However,the jams could be rejected with a 4-element circle array antenna in space and polarization domains.The reference element locates at the origin of a circle and the other three dual-linearly-polarized elements are on the circumference uniformly.The LMS adaptive filtering algorithm is employed based on power inversion criterion,which adjusts the weight vector of the three dual-linearly-polarized elements and makes the equivalent polarimetric match factor be zero closely.Then the jams are rejected in polarization domain.The nulling antenna works without the space information of the signal,which makes it be implemented very easy.Furthermore,the degree of the freedom could reach 6 and the number of the interference signals could be more than the number of the array elements.The simulations prove that 4-element array could eliminate 6 interferences at most.And the jam would be rejected even with the same direction of arrival as desired signal if their polarizations are different.