Shanxi Key Laboratory of Information Detection and Processing, North University of China, Taiyuan 030051, China.
National Key Laboratory of Electronic Measurement Technology, North University of China, Taiyuan 030051, China.
Sensors (Basel). 2019 Nov 20;19(23):5067. doi: 10.3390/s19235067.
bstract: The positioning technology to find shallow underground vibration sources based on a wireless sensor network is receiving great interest in the field of underground position measurements. The slow peaking and strong multi-waveform aliasing typical of the underground vibration signal result in a low extraction accuracy of the time difference and a poor source-positioning accuracy. At the same time, the transmission of large amounts of sensor data and the host computer's slow data processing speed make locating a source a slow process. To address the above problems, this paper proposes a method for high-precision time-difference measurements in near-field blasting and a method for its hardware implementation. First, based on the broadband that is typical of blast waves, the peak frequency of the P-wave was obtained in the time-frequency domain, taking advantage of the difference in the propagation speed of the P-wave, S-wave, and the surface wave. Second, the phase difference between two sensor nodes was found by means of a spectral decomposition and a correlation measurement. Third, the phase ambiguity was eliminated using the time interval of the first break and the dynamic characteristics of the sensors. Finally, following a top-down design idea, the hardware system was designed using Field Programmable Gate Array(FPGA). Verification, using both numerical simulations and experiments, suggested that compared with generalized cross-correlation-based time-difference measurement methods, the proposed method produced a higher time-difference resolution and accuracy. Compared with the traditional host computer post-position positioning method, the proposed method was significantly quicker. It can be seen that the proposed method provides a new solution for solving high-precision and quick source-location problems, and affords a technical means for developing high-speed, real-time source-location instruments.
基于无线传感器网络的浅层地下振源定位技术在地下定位测量领域受到广泛关注。地下振动信号具有缓慢的峰值和强的多波型混淆，导致时差提取精度低，源定位精度差。同时，传感器数据的大量传输和主机数据处理速度慢使得定位过程缓慢。针对上述问题，本文提出了一种近场爆破高精度时差测量方法及其硬件实现。首先，基于爆炸波典型的宽带，利用 P 波、S 波和表面波的传播速度差异，在时频域中得到 P 波的峰值频率。其次，通过频谱分解和相关测量找到两个传感器节点之间的相位差。然后，利用首波时间间隔和传感器的动态特性消除相位模糊。最后，采用自顶向下的设计思想，使用现场可编程门阵列（FPGA）设计硬件系统。通过数值模拟和实验验证，与基于广义互相关的时差测量方法相比，所提出的方法具有更高的时差分辨率和精度。与传统的主机后置定位方法相比，该方法速度显著提高。由此可见，所提出的方法为解决高精度、快速的声源定位问题提供了新的解决方案，为开发高速实时声源定位仪器提供了技术手段。
