摘要利用超声波模块作为传感器进行测测距已经是非常常见的测距方法之一，这种测距方法有点有许多，价格低廉，精确性高，受环境影响较小，操作简便，携带性好，所以我们就对超声波应用于测距系统进行了研究，在研究的基础上设计了多传感器超声波测距系统[1]。73450

关于超声波测距系统的研究已经非常非常多了，各种各样的系统和算法层出不穷。由于超声波是声波的特性，很多系统都是使用补偿损失，放大信号等方法来尽可能减小温度，湿度等等因素对声波本身的影响，为了打到减小误差的目的有的系统也会采用各种算对系统补偿。但是这些方式从根本上来说就是不肯能将误差完全消除的。所以我们换了个角度，思考怎样从本源来解决超声波测距中的系统外因素的影响，这就是我们设计的多传感器超声波测距系统。

多传感器超声波测距系统的本质思想就是利用多个传感器先进行实验环境下的测声速，并将声速记录下来，只要环境不改变声速在理论上是不会改变的。再将测得的声速带入测距系统中进行计算从而避免了环境因素的影响也就无需补偿修正可以直接计算距离，这样的测距系统的精度就提高了。本设计通过多传感器以及外部计数器（150MHZ）等方式方法来提高系统精度[3]。从而排除掉实验中众多的环境因素的影响。首先，我们选用两组超声波接收和发射装置发送超声波的同时利用高频的外部计数器进行计数（由于精度要求单片机内部计数器不能够打到要求），预先将两个超声波传感器模块放置在固定距离的位置上，当位置靠前的超声波模块A的接收端收到发射端发射出的超声波信号时单片机给外部芯片进行计数，位置靠后的超声波模块B接收端接收到信号时外接计数器计数停止。在整个系统中用多个传感器模块预先进行测速即：超声波模块A、B之间的位置差和外部计数器测量出的时间计算出进行实验时的环境下的声速V，利用单片机进行计算和存储，再利用超声波的原理计算出传感器距离目标的距离。相较于补偿环境因素（温度、湿度等）方式更为直接也能够更为准确的打到测距的目的。

毕业论文关键词：超声波测距  高频计数器  多传感器  单片机

Multi sensor ultrasonic distance measuring system

Abstract Using ultrasonic module as a sensor for measuring range is one of the very common ranging method, there were many this ranging method is a little, low cost, high accuracy, less affected by the environment, simple operation, good portability, so we studied the ultrasonic wave applied to ranging system, on the basis of the study of multisensor ultrasonic ranging system is designed。

Research on distance measuring system has been a lot, all kinds of system and algorithm emerge in endlessly。 Due to the ultrasonic wave is one of the characteristics of sound waves, many systems are used to compensate the losses, amplify signals such as ways to minimize temperature, humidity and so on the influence of factors on the sound wave itself, in order to hit the error is reduced in some system will be used in a variety of compensation to the system。 But the way is basically not able to completely eliminate the error。 So we change a point of view, thinking how to solve the system of ultrasonic ranging from a source outside factors, this is our design of multi-sensor ultrasonic ranging system。

The essence of the ultrasonic ranging system multisensor thought is to use multiple sensor of measuring sound velocity experiment environment, first to record the speed of sound, as long as the environment does not change the speed of sound in theory is not change。 Then measured the speed of sound into ranging system is calculated so as to avoid the influence of environmental factors are fixed distance can be calculated directly without compensation, the precision of the ranging system is improved。 This design through multi-sensor and external counter (150 MHZ), and other methods to improve the system accuracy。To rule out experiments of the influence of environmental factors。 First of all, we choose two groups of ultrasonic receiving and emitting devices send external counter at the same time by using high frequency ultrasound counted (due to precision demands MCU internal counter will not be able to hit), place the two ultrasonic sensor module in advance in the position of the fixed distance, when the position of the ultrasonic module A receiving end receives the ultrasonic transmitter emitting signal microcontroller to external chip count, the location of the ultrasonic module B external counter count to stop when the receiver to receive signals。 In the whole system with multiple sensor module in advance speed: the location of the difference between A and B ultrasonic module and external counter measure the time when calculate the experiment under the environment of sound velocity V, use of single-chip microcomputer for computing and storage, the principle of using ultrasonic to calculate the distance of the target from sensors。 Compared with compensation of environmental factors (temperature, humidity, etc。) more directly can more accurately hit the purpose of the range。