基于MSP430的相位式激光测距仪的研究

【作者】 张涛；

【导师】 严高师；

【作者基本信息】 电子科技大学 ， 光学工程， 2006， 硕士

【摘要】 激光测距是随着激光技术的出现发展而发展起来的一种精密测量技术,因其较高的精确度特性而广泛应用在军事和民用领域。本文首先介绍了激光测距原理,然后从激光雷达测距理论出发,以激光雷达作用距离方程、激光的大气传输特性对测距的影响、激光雷达的信噪比作为理论基础,进行了方案设计。传统的相位激光测距大部分都采用差频数字测相,差频测相的优点在于由于频率的降低,这样必然意味着测距精度的提高,但其缺点是测距速率低。根据本课题测距精度和测距速率的指标要求,针对现有激光测距方法的局限性,提出了双频测相相位式激光测距方法。该方法通过MSP430单片机和先进的CPLD技术实现双频测相:粗测通过采用对鉴相脉冲填充高频脉冲的办法来实现;精测则利用时间-电压转换法对鉴相脉冲进行转换,然后由模数转换器ADC对转换电压进行采样,通过单片机对ADC的输出值进行计算处理获得精测值。该方法可以弥补现有一般相位激光测距机无法克服的缺陷,既可以保证一定的测距精度,又可以提高测距速率,从而可以对动态目标进行实时测量。论文完成了基本的硬件电路设计。硬件设计以MSP430单片机作为整个系统的控制核心;通过单片机控制CPLD和ADC来获得粗测和精测值;模拟电路部分包括激光调制驱动电路和接收电路以及APD高压偏置电路;进行串行通信电路和电源电路的设计。系统样机进行了调试,并对试验结果进行了分析,初步满足预期的指标要求。样机系统实验表明测距精度达到9.9mm,测距速率达到每秒4次,得到了比较理想的结果,研究工作取得了重要进展。最后本文对系统以后的改进部分进行了一些探讨,并对研究工作做了总结和展望。更多还原

【Abstract】 The laser ranging is a technology for precision measurement and it is developing along with the development of the laser technology. The laser ranging is extensively used in the military field and the civil field because of its high accuracy.The theory of laser range finder is firstly introduced in this paper. Then based on the laser radar ranging theory, the laser radar ranging equation, the effect of the travel characters of the laser in the air on the measurement and the laser ranging SNR equation are discussed. The scheme is designed based on these researches.For traditional laser rang finders, most of them use heterodyne method as the phase shift measurement. The advantage of heterodyne method is the high measurement accuracy, but its disadvantage is the low measurement velocity. According to the requirement of measurement accuracy and velocity, a novel twofold frequency laser ranging method based on phase ranging technology is proposed. By using MSP430 micro controller unit and CPLD technology, this method realized twofold frequency phase ranging: The rough measurement of the distance is realized by countering high frequency pulses which are filled in discriminating phase pulses; The accurate discriminating phase pulses are converted by using the method of time to voltage conversion, and then the ADC device samples the converted voltage, so the accurate measurement of the distance is obtained by processing the ADC samples through micro controller unit. Various technical measures are adopted to make sure the accuracy of the laser ranging and the requirement of the high velocity of the laser ranging is satisfied. So the real-time measurement of the dynamic target is satisfied by using this method. According to the phase laser rang finder design scheme, the fundamental hardware circuits are designed. The hardware designation uses the MSP430 micro controller unit as the control center. The rough and accurate values of the measurement are obtained by using CPLD and ADC devices. The analog circuits mainly included the modulating and driving circuit of the laser, receiving circuit and APD high-voltage biased circuit. Serial communication circuit and power circuit are designed. The system更多还原