一种音频测距信号到达时刻估计方法

Estimate method of time of arrival in acoustic ranging

对音频测距信号到达时刻的精确估计是利用音频信号实现远距离无线传感器网络节点定位的关键。研究比较了几种常用的音频测距信号到达时刻估计方法,并提出了一种基于数字整流处理的到达时刻估计方法。它包括信噪比增强、去除直流分量、全波整流、低通滤波、到达时刻估计等过程。该方法在以dsPIC6014A单片机为控制器的节点进行了实验验证,测试结果表明:处理4 096点(12位量化)数据的计算时间约为1.5 s(10MHz时钟),30m距离处的时间值估计误差小于3.5%。

Precise estimate of ranging signals＇ TOA（ time of arrival）is a key for wireless sensor networks nodes＇ acoustic localization. Several acoustic signals＇ TOA estimate methods are compared and an estimate method based on the digital signal rectifying process is introduced. It includes the following steps ： increase of signal noise ratio, remove of DC（direct current）value,full-wave rectifying process, low-pass filter process and TOA estimate. It is implemented with a dsPIC6014A microcontroller. Test results show that the time of computing is about 1.5 s （10MHz clock） ,sample length is 4 096 （12bits of each sample data）. The estimate error of TOA is less than 3.5% with 30m distance.