脉冲激光测距仪的设计-课程设计

目录第一章绪论············································································································································································································································11111.11.11.11.1设计背景····································································································································································································································1111第二章脉冲激光测距仪的工作原理····················································································································22222.12.12.12.1测距仪的简要工作原理····························································································································································2222第三章脉冲激光器的结构及工作过程········································································································33333.13.13.13.1激光脉冲测距仪光学原理结构········································································································33333.1.13.1.13.1.13.1.1测距仪的大致结构组成············································································································33333.23.23.23.2主要的工作过程····················································································································································································44443.33.33.33.3主要部件分析：················································································································································································44443.3.13.3.13.3.13.3.1激光器（一般采用激光二极管）····························································44443.3.23.3.23.3.23.3.2激光二极管的特性········································································································································55553.3.33.3.33.3.33.3.3光电器件（采用雪崩光电二极管APDAPDAPDAPD）················6666第四章影响测距仪的各项因素············································································································································77774.14.14.14.1光脉冲对测距仪的影响············································································································································77774.24.24.24.2发散角对测距仪的影响············································································································································8888第五章测距仪的光电读数显示············································································································································99995.15.15.15.1距离显示原理及过程························································································································································99995.25.25.25.2测量精度分析····················································································································································································101010105.35.35.35.3总述····································································································································································································································11111111参考文献························································································································································································································································111111111第一章绪论1.1设计背景在当今这个科技发达的社会，激光测距的应用越来越普遍。在很多领域，如电力，水利，通讯，环境，建筑，地质，警务，消防，爆破，航海，铁路，军事，农业，林业，房地产，休闲、户外运动等都可以用到激光测距仪。激光测距仪一般具有精确度和分辨率高、抗干扰能力强、体积小、重量轻等优点，因而应用领域广、行业需求众多，市场需求空间大。当前激光测距仪的发展趋势是向测量更安全、测量精度高、系统能耗小、体积小型化方向发展。激光测距仪一般采用两种方法来测量距离：脉冲法和相位法。而其中脉冲激光测距的应用领域也是越来越宽广，比如，地形测量、战术前沿测距、导弹运行轨道跟踪以及人造卫星、地球到月亮距离的测量等。脉冲激光测距法是利用激光脉冲持续时间非常短，能量相对集中，瞬时功率很大（可达几兆瓦）的特点，在有合作目标的情况下，脉冲激光测距可以达到极远的测程；如果只是利用被测目标对脉冲激光的漫反射所取得的微弱反射信号，也是可以测距的。因而脉冲激光测距法应用较多。2第二章脉冲激光测距仪的工作原理2.1测距仪的简要工作原理现在就脉冲激光测距简要叙述其工作原理。简单地讲，脉冲法测距的过程是这样的：测距仪发射出的激光经被测量物体的反射后又被测距仪接收，测距仪同时记录激光往返的时间t，光速c和往返时间t的乘积的一半，就是测距仪和被测量物体之间的距离D。一般一个典型的激光测距系统应具备以下四个模块：激光发射模块；激光接收模块；距离计算与显示模块；激光准直与聚焦模块，如图2-1所示。系统工作时，由发射单元发出一束激光，到达待测目标物后漫反射回来，经接收单元接收、放大、整形后到距离计算单元计算完毕后显示目标物距离。图2-1脉冲激光测距系统原理框图在测距点向被测目标发射一束强窄激光脉冲，光脉冲传输到目标上以后，其中一小部分激光反射回测距点被测距系统光功能接收器所接受。假定光脉冲在发射点与目标间来回一次所经历的时间间隔为t，那么被测目标的距离D为：距离计算与显示单元激光发射单元激光接受单元目标物32ctD=（2.1）式中：c为激光在大气中的传播速度；D为待测距离；t为激光在待测距离上的往返时间。第三章脉冲激光器的结构及工作过程3.1激光脉冲测距仪光学原理结构发射激光反射镜反射激光束滤光片图3-1激光脉冲测距仪的光学原理图3.1.1测距仪的大致结构组成如图3-1所示的脉冲激光测距仪。它主要由脉冲激光发射系统、电源激光器发射望远镜接收望远镜光电器件放大整形时间测量显示器目标物4光电接收系统、门控电路、时钟脉冲振荡器以及计数显示电路组成。3.2主要的工作过程其工作过程大致如下：首先接通电源，复原电路给出复原信号，使整机复原，准备进行测量；同时触发脉冲激光发生器，产生激光脉冲。该激光脉冲有一小部分能量由参考信号取样器直接送到接收系统，作为计时的起始点。大部分光脉冲能量射向待测目标，由目标反射回测距仪的光脉冲能量被接收系统接收，这就是回波信号。参考信号和回波信号先后由光电探测器转换成为电脉冲，并加以放大和整形。整形后的参考信号能触发器翻转，控制计数器开始对晶格振荡器发出的时钟脉冲进行计数。整形后的回波信号使触发器的输出翻转无效，从而使计数器停止工作。这样，根据计数器的输出即可计算出待测目标的距离。3.3主要部件分析：3.3.1激光器（一般采用激光二极管）半导体激光二极管（LD）是实用中最重要的一类激光器，它体积小、寿命长、并可以采用简单的电流注入的方式来泵浦。因此，半导体激光二极管在激光通信、光存储、激光测距以及激光雷达等都有着广泛的应用。半导体激光器工作原理和其他激光器一样，即都是基于受激发5射。要使得激光器得到相干的受