利用系统辨识的星敏感器模型修正与测角精度检测

2.中国科学院大学,北京100049)摘要:为了提高星敏感器的测角精度,提出了一种采用系统辨识法对星敏感器模型进行修正以及测角精度检测的方法。首先分析了星敏感器的理论测量模型以及像面坐标与星点目标的空间位置关系,然后给出了用模型修正来提高星敏感器测角精度的原理和数学模型。修正模型由系统辨识方法得到,同时为了提高辨识精度,文中采用将星敏感器像面划分为多个区域,每个区域单独建模辨识的方式。最后利用某星敏感器进行了实验,利用该方法进行模型修正后,星敏感器的测角精度为σx=1.68″、σy=1.91″,而修正前的测角精度为σx=17.43″、σy=23.46″。结果表明,采用该方法可以使星敏感器测角精度得到大幅提高,同时也完成了测角精度的检测。

The Model Updating and Angle Measurement Accuracy Testing of Star Sensor Using System Identification

To satisfy rigid performance specifications, a feedback control was presented for zoom optical lens plants. In order to improve the angle measurement accuracy of the star sensor, a novel approach is proposed as the model updating and angle measurement accuracy testing of the star sensor using system identification. First, the theoretical measuring model of the star sensor and the spatial relation between image coordinates of the star sensor and target are analyzed. Secondly the basic principle and the measurement model are given for getting more accurate measuring model by updating the model of the star sensor. The correction model of the star sensor is established by means of system identification technique. For improving the angle measurement accuracy of star sensor，the CCD image plane of star sensor is divided into multiple regions, and the model of every region is built by system identification individually. The experiment is conducted with a star sensor. The experimental results show that the angle measurement accuracy of x and y directions is 1.68″ and 1.91″ after calibration, but 17.43″ and 23.46″ before calibration. The results show that the angle measurement accuracy of the star sensor is improved with this method.