基于光纤振动信号过零检测的序贯概率比振源检测算法

Study on the Algorithm of a Modified SPRT Vibration Source Detection Based on Zero-Crossing Detection for Optical Fiber Vibration Signals

在光纤振动信号检测系统中,使用相干光时域反射COTDR技术,可检测长距离的光缆振动信号,但反射回的光信号都有大量的振动杂波和噪声.已有的振源检测技术都是采用单级振源检测机制,这将导致系统的虚警率不稳定和检测性能下降.由于微弱振源信号变化不明显,已有的振源检测技术对微弱振源的检测显得无能为力.为此,本文通过分析振动信号的过零检测模型和序贯概率比检测的关系,提出了一种多级振源检测算法,使虚警率稳定在一个可控范围内,同时提高了对微弱振源的检测能力.最后,用现场实验数据验证了该算法的有效性和可行性.

The optical fiber vibration can be detected by Coherent Optical Time Domain Reflect technique. Besides vibration, the reflected signals include clutters and noises. A lot of work has been done on the vibration source detection such as by using single stage detection, which leads to the unstable false alarm rate and a considerable decrease in detection capacity. By applying the existing vibration source detection, the weak vibration source could not be detected because of its weak change. To overcome these problems, an algorithm with multistage vibration source detection is proposed, which employs some soft rules based on the relationship of zero-crossing model and SPRT. The results from the data of the field experiments are given to demonstrate the efficiency of the algorithm. The false alarm rate is stable at a controllable range, and the detection performance of the weak vibration source has been improved.