一种脉冲式半导体激光云高仪的关键技术问题研究

Study on a Pulsed Semiconductor Laser Ceilometer

云是发生在高空的水汽凝结现象,其生成、外形特征、量的多少、分布及其演变,不仅反映了当时大气的运动、稳定程度和水汽状况等,而且也是预示未来天气变化的重要征兆之一。正确分析云的变化,是了解认识大气物理状况,掌握天气变化规律的一个重要因素。本文介绍了一种新型的脉冲式半导体激光云高自动测量系统,设计了激光收发同轴的光学系统,实现了无盲区的云探测;研制了半导体激光器驱动模块、接收低噪声前置放大、高速采集和信号处理等电路;在数据处理方法上,提出了小波信号特征提取法,能有效地识别出云层信息。研制的半导体激光云高自动测量系统能够给出云底、云高信息,所获得的结果与SAGEII卫星所测的卷云高度基本一致,证明仪器能满足气象观测对云层参数测量的要求,具有一定的可行性。

Cloud,which relates to the phenomenon of water vapor condensation,is not only representative of the atmospheric motion,stability and water vapor,but also an important indicator of weather forecast.Cloud characteristics including its formation,shape,amounts,distribution and evolution can be used to make a further study on the atmosphere.So a new-developed ceilometer based on the pulsed semiconductor laser is introduced in this paper.The whole system is made of three main modules.In the optical module,the designed co-axial optical system can overcome the shortcomings of blind area cloud detection.In electric module,the laser-driven sub-module,low-noise amplifier receiving sub-module and the high-speed signal sampling sub-module are precisely designed.In the data processing module,the wavelet transform algorithm is also described in detail.The finally fashioned ceilometer system can provide the information of cloud heights and cloud optical information,which can fill the gap of pulsed laser cloud detecting technology at home and satisfy the need of weather observation for clouds.