一种高精度超声波到达时刻的检测方法

Method to precisely measure arrival time of ultrasonic

针对超声波到达时刻精密测量的要求,提出一种超声波达到时刻精确检测算法。采用数字处理技术,利用A/D转换数据,根据超声信号达到最大值经过的周期数,确定超声到达判断的门限电平,通过直线拟合方法计算出超声波到达时刻。该方法采用动态阈值,克服了采用固定门限电平受信号幅度影响的缺点。该方法仅通过简单搜索和数学运算,在较低信号采样率条件下,能够实现ns级精度的检测,为测距、目标跟踪定位、流量检测等高精度超声波检测提供一种计算量低、精度高的检测方法。试验与仿真结果验证了该方法具有较高的精度和实时性。

Aiming at the requirements of precisely measuring arrival time of ultrasonic, a high precision measurement method for arrival time of ultrasonic was proposed. The method adopts digital signal processing technology, searches the sample data of ultrasonic signal from A/D, determines the threshold level of the arrival of ultrasonic signal according to the number of ultrasonic signal periods before the signal reaches its maximum, and adopts straight line fitting method to calculate the arrival time of the ultrasonic. Because the threshold level is a dynamic value proportional to the maximum of the ultrasonic signal, the defect of using fixed threshold level to detect the arrival time of ultrasonic signal is overcome. Under low sampling rate, the method could achieve the measurement accuracy of nanosecond level with only simple data searching and computation, which provides an ultrasonic measurement method with low computation complexity and high precision for ultrasonic ranging, localization, tracking and flow measurement. Experiment and simulation results show that the proposed method possesses good accuracy and real time performance.