新型LED光源气溶胶探测雷达系统优化设计与初步实验

Optimal Design and Preliminary Experiments on New Type of LED Light Source Radar System for Aerosol Detection

为了实现近地面、多波长气溶胶时空探测,克服激光波长可选择性不足的问题,利用LED丰富的光谱特性,设计了一种新型发光二极管(LED)光源雷达。LED能量小且发散角大,其出光能量、发散角、接收视场角和几何重叠因子都会对LED光源雷达探测距离产生影响。针对共轴LED光源雷达系统的特点,分析了几何重叠因子的特征和计算方法,详细讨论了光源发散角和接收视场角对几何重叠因子的影响。结合LED光源的特点,利用美国标准大气模型对雷达系统的探测能力进行了仿真,优化了光源发散角和接收视场角,在LED能量一定的情况下获得了最大的探测距离。搭建了LED光源雷达系统并完成了初步实验观测,结果表明该雷达夜晚能够接收到240m远处的大气回波,验证了雷达探测低层大气气溶胶的能力。

In order to achieve near-ground and multi-wavelength space-time detection of aerosol and overcome the problem of lack of selectable laser wavelength, a new type of light-emitting diode （LED） light source radar is designed using the abundant spectral characteristics of LED. The energy of LED is low, and the divergence angle is large. The output energy, divergence angle, receiver＇s field angle and geometric overlap factor will affect the detection range of LED light source radar. In this paper, aiming at the characteristics of the coaxial LED light source radar system, the features and calculation methods of the geometric overlap factor are analyzed, and the influences of light source divergence angle and receiver＇s field angle on the geometric overlap factor are discussed in detail. Combined with the characteristics of the LED light source, the detection capability of the radar system is simulated by US standard atmospheric model, and the light source divergence angle and receiver＇s field angle are optimized. The maximum detection range is got at the certain LED energy. The LED light source radar system is built and preliminary experimental observation is completed. The experimental results show that the designed radar can receive the atmospheric echo signal at the distance of 240 m at night. It verifies the radar＇s ability to detect low-level atmospheric aerosol.