提出了一种基于变长扫描模型的故障检测方法.该方法对待检测的时间序列数据进行差减操作求得相应的差减序列.由于跳跃点会影响两个相邻差减序列的统计特性,因此通过当前差减序列来估计即将来临的下一时刻的取值区间,进而判断下一时刻是否是跳跃点,从而实现故障检测.考虑算法的时间复杂度,设计了扫描窗口的变长机制,以在检测精度和检测速度上寻求平衡.通过仿真实验讨论了置信度和扫描窗口长度的取值问题.最后将该故障检测算法应用到GPS/INS组合导航系统中.试验表明,该故障诊断方法能够有效地检测出数据中的跳跃点,提高了滤波器的精度.
A fault detection method based on varying-length scanning model is proposed.This method performs minus-operation on the time series data to be detected and then gets the corresponding difference minus sequence.The statistic characters of two neighboring difference minus sequences are affected due to the change point,so the proposed method estimates the value interval at next time through current difference minus sequence,and then realizes fault detection by estimating whether the change point exists at next time.Considering the time complexity of the algorithm,a scanning window size mechanism is designed to bring a balance between the detection speed and precision.The question to select the confidence interval and scanning window size is discussed by a simulation experiment.This fault detection method is applied to integrated GPS/INS(global positioning system / inertial navigation system) navigation system.The experiment shows that it can detect the change point in the data effectively and enhance the precision of filter.