基于递推最小二乘算法的光纤振动定位系统

为了解决光纤振动定位算法中互相关稳定性差、最小均方收敛速度慢的问题,采用递推最小二乘算法、滑动平均原理、早迟门原理,设计了一套稳定且响应迅速的光纤振动定位系统。光路部分基于双马赫-曾德尔干涉结构,硬件平台以高速采集板结合现场可编程门阵列实现定位。在一段160m的光路上进行重复敲击实验,对取得的振动数据分多段分别计算定位结果,去除最大值、最小值后剩余定位结果取平均值以提高定位精度。结果表明,相对于互相关,递推最小二乘随着迭代次数增加,单次定位结果稳定不会发生偏移,且其定位收敛速度是最小均方的3倍左右;在采样率为10MHz时,系统实际响应时间约0.3s,定位误差范围在±6m,且定位稳定可靠。该研究对于光纤定位系统中定位算法的改进、定位精度的提高是有积极意义的。

Fiber optic vibration positioning system based on recursive least-squares algorithm

In order to solve the problems of poor cross-correlation stability and slow minimum mean square convergence in optical fiber vibration location algorithm, recursive least squares algorithm, moving average principle and early-late gate principle were adopted. A stable and fast response optical fiber vibration positioning system was designed. Optical path was based on double Mach-Zehnder interference structure. Hardware platform used high-speed acquisition board and field-programmable gate array to realize positioning. Repeated knocking experiments were carried out on 160m optical path. The obtained vibration data were computed separately in several segments. After removing the maximum and minimum values, the residual positioning results were averaged to improve the positioning accuracy. The results show that, as the number of iterations increases, recursive least squares method can stabilize the single positioning result without migration, compared with cross-correlation. Convergence rate is about 3 times of minimum mean square. At sampling rate of 10MHz, actual response time of the system is about 0.3s. The range of positioning error is ±6m. The positioning is stable and reliable. This research has positive significance for the improvement of location algorithm and positioning accuracy in optical fiber positioning system.