精确的精跟踪系统模型为研究精跟踪的控制算法，找到影响其动态、静态性能的关键因素提供了重要的条件。设计了精跟踪辨识系统，该系统包括：快速倾斜镜、CCD、DA以及相关的电子设备。精跟踪模型传统上被认为是一个二阶系统，通过输入输出数据、模型类和最小二乘等价准则等一系列过程确定精跟踪的模型。为了评估该辨识方法的性能，将最小二乘辨识法得到的模型与传统的频率响应法得到的模型做比较。通过验证发现，两种模型的输出与实际系统输出的模型残差平方和分别为8.20和89.52，相关系数分别为0.98和0.95。结果表明，最小二乘法得到的精跟踪模型比频率响应法得到的模型更准确地反映出实际系统的特性。

The precise model of the fine tracking system (FTS) provides a crucial condition to study the control strategy, and find the key factors which impact the dynamic and static characteristics of FTS. The fine tracking identify system is designed in this paper which includes the fast steering mirror (FSM), the charge coupled device (CCD), the Digital to Analog Converter (DAC) and the associated electronics. Traditionally, the model of the FTS is considered as a second order model, a series of process such as the input and output data, the model class and the equivalent standards of the least square method is presented to obtain the model. In order to evaluate the performance of the least square identification method, the model is compared with the one obtained by the traditional frequency response method. The residual sum of squares between these two model outputs and the actual output are 8.20 and 89.52, respectively; while the correlation coefficients are 0.98 and 0.95, respectively. The results indicate that the model of the FTS obtained by the least squares identification method is more accurate than the one obtained by the frequency response method.