用音频信号实现无线传感器网络节点间距测量

Measurement of Wireless Sensor Network Nodes Distances with Audible Sound

介绍了一种利用音频信号实现节点间距自主测量的无线传感器网络节点。节点硬件系统包括dsPIC6014A微控制器,512KB的SRAM,2.4G波段的RF收发模块、音频收发模块及电源管理模块等。节点通过测量RF同步信号与音频信号的时间差来测量节点间的间隔距离。与国内外的研究相比,节点可以自主完成测距信号的采集、存储和数据分析、计算工作。节点通过采用多次测量数据累加平均及IIR数字滤波技术提高了测距信号的信噪比,利用幅度分析实现了测距信号的到达时刻判别。测试数据表明,该节点最远测距距离可达30m,误差小于3%。

A node with acoustic ranging function was introduced. It included a dsPICAS014A microcontroller, 512 KB SRAM, a 2.4 G RF transceiver, a buzzer, a microphone and a power manager unit. The nodeg distances were measured by time difference of arrival between RF and acoustic signals. The node accomplished collection and store of the audible sound, data analysis and distances calculation. The signal noise ratio of the received audible sound was increased by multimeasurement and IIR digital filter. The audible sound＇s arrival time was calculated by the amplitude of the data. The test results show that the node can measure the distance as far as 30 m with error〈3%.