根据遗忘因子作用于数据的一般形式以及Hankel矩阵构造形式,导出在变遗忘因子作用下的Hankel矩阵无偏更新形式,并据此设计了新的变遗忘因子递推子空间辨识算法.分别从与无偏更新的Hankel矩阵接近程度、跟踪性能以及对距离信息的敏感性等方面比较了改进方法、固定遗忘因子方法以及传统的变遗忘因子方法的性能.仿真结果表明,改进算法具有更好的性能. According to the general form of the forgetting factor acting on the data and the Hankel matrix construction form, the unbiased update form of the Hankel matrix under the effect of variable forgetting factor is deduced, and a new algorithm of spatial identification of forgetting factor recursive subspace is designed. The unbiased updated Hankel matrix approximation, tracking performance and sensitivity to distance information are compared with the improved method, the fixed forgetting factor method and the traditional variable forgetting factor method.The simulation results show that the improved algorithm has better performance .