中文摘要：

卫星智能天线的一项核心技术是波束成形。传统调零算法是波束成形算法的一种，它对所有干扰置零，需要求导向矢量矩阵的逆矩阵，运算比较复杂。逐个调零算法和调零算法的目的基本一致，也是对干扰置零，它不必求矩阵的逆，但是对干扰的置零能力有限。文章提出基于迭代的逐个调零算法，是对逐个调零算法的改进，在不增加太多计算量的情形下，提高了干扰抑制能力，最后给出了仿真结果，验证了改进算法的可行性和有效性。

英文摘要：

One of the key technologies for smart antenna on satellite is beamforming. Traditional null-steer algorithm is a widely used beamforming algorithm. It can have nulls in the directions of interferences in the pattern, and restrain all the interferences. However, it needs to calculate the contrary matrix and it is complex, Stepwise null-steer algorithm, which does not need to calculate the contrary matrix, has the same aim with traditional null-steer algo- rithm, but it has poor performance in some situation, A new iterative null-steer algorithm is proposed in this paper. It is an improvement for stepwise null-steer algorithm, and it can improve the performance of interference restraint without increasing much computing load. Numerical examples demonstrate the effectiveness of the algorithm.