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基于无线传感网络(WSN)和超声波实现的室内定位系统,是利用超声波在空间飞行的时间和速度,求出定位节点到各个锚节点的距离,然后利用三边测量的定位方法求出定位目标节点的坐标.这种定位系统通常采用包络检测法,通过检测包络的最大值点来计算超声波的到达时间.考虑实际电路系统中噪声的影响,实际检测到的最大值点都会在真实值左右波动,从而降低系统的稳定性和精度.本文采用数字锁相放大,相比现有的方法,能有效地减少噪声和干扰的影响,极大地提高了系统的定位精度和系统的抗干扰能力.通过仿真和实际应用实验,不考虑超声波反射,距离测量误差能够达到2mm,数据的标准差最大值达到0.15mm,相对于目前研究领域的最高值0.3mm,降低了50%.
Based on wireless sensor network (WSN) and ultrasonic indoor positioning system, is the use of ultrasonic time and velocity in space flight, find the distance from the positioning node to each anchor node, and then use the three-way positioning method to find the positioning target The coordinates of the node.The positioning system usually adopts the envelope detection method to calculate the arrival time of the ultrasonic wave by detecting the maximum point of the envelope.According to the influence of the noise in the actual circuit system, the actual detected maximum point will be the true value So as to reduce the stability and accuracy of the system.In this paper, digital phase-locked amplification, compared with the existing methods, can effectively reduce the impact of noise and interference, greatly improving the system’s positioning accuracy and system anti-interference ability Through simulation and practical experiments, without considering the ultrasonic reflection, the distance measurement error can reach 2mm and the standard deviation of the data reaches 0.15mm, which is 50% lower than the highest value of 0.3mm in current research field.