CAJ | 학술논문

现有的向量加权稳健波束形成方法只有在指向误差较小的情况下才能有效估计目标的信号功率；矩阵加权波束形成方法在指向误差较大时，虽然可以估计目标的信号功率，但是它的系统实现复杂度与向量加权稳健波束形成方法相比较大。针对以上问题，该文提出基于半正定秩松弛(SDR)方法的稳健波束形成，该方法优化模型中的目标函数与Capon算法的目标函数相同，优化变量为加权向量的协方差矩阵，并约束方向图的主瓣幅度波动范围、旁瓣电平，协方差矩阵的秩为1。应用 SDR 方法求得加权向量的协方差矩阵，将该矩阵中的每一行(列)转化为加权向量，然后选择使得方向图主瓣与0 dB之间失真最大值最小的一个加权向量。该方法的系统实现复杂度与传统向量加权方法一致，对信号功率的估计性能与矩阵加权方法相当。仿真实验验证了该文方法可以得到理想的方向图形状，并且可以在大指向误差条件下有效估计信号功率。
현유적향량가권은건파속형성방법지유재지향오차교소적정황하재능유효고계목표적신호공솔；구진가권파속형성방법재지향오차교대시，수연가이고계목표적신호공솔，단시타적계통실현복잡도여향량가권은건파속형성방법상비교대。침대이상문제，해문제출기우반정정질송이(SDR)방법적은건파속형성，해방법우화모형중적목표함수여Capon산법적목표함수상동，우화변량위가권향량적협방차구진，병약속방향도적주판폭도파동범위、방판전평，협방차구진적질위1。응용 SDR 방법구득가권향량적협방차구진，장해구진중적매일행(렬)전화위가권향량，연후선택사득방향도주판여0 dB지간실진최대치최소적일개가권향량。해방법적계통실현복잡도여전통향량가권방법일치，대신호공솔적고계성능여구진가권방법상당。방진실험험증료해문방법가이득도이상적방향도형상，병차가이재대지향오차조건하유효고계신호공솔。
The existing vector weighted robust beamforming is able to estimate the signal power of target only in situations of a small steering angle error. For a larger steering angle error case, although the matrix weighted beamforming can effectively estimate the signal power of the target as well, the system implementation is more complicated than above mentioned vector weighted. In order to solve these problems, this paper presents a new robust beamforming approach based on SemiDefinite rank Relaxation (SDR). Detailed description of the proposed method are given as follows: the optimal model has the same objective as that of the Capon algorithm; the optimization variable is the covariance matrix of weight vector with constraints posed on the ripple of mainlobe amplitude and sidelobe level, and the rank of covariance matrix is 1;the covariance matrix of the weight vector can be obtained by the SDR method, and each row or column of the matrix is translated into weight vector, then a weight vector is chosen which allows it become minimal one in the maximum distortions between the mainlobe of beampattern and 0 dB. The system implementation complexity of the proposed method is the same as the vector weighted methods, and the signal power estimation performance is similar to the matrix weighted method. The simulation results show that the desired beampattern shape and effective estimation of signal power can be obtained under the condition that the large steering angle error exists.