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激光大气传输在激光测距、遥感、激光制导以及激光自由空间通信等领域应用广泛。传输前后激光能量的透过率决定了接收端光学系统入射光强的最大值。因此,对影响透过率各种因素的全面研究十分必要。采用大气辐射传输计算软件MODTRAN对激光大气传输路径上的气体分子和气溶胶分布进行模拟,综合考虑地形、海拔、气候条件以及天气变化等众多因素的影响,对激光大气传输透过率的变化进行系统分析。仿真结果表明:激光的大气传输透过率具有波长依赖性,其受纬度和季节变化的影响程度也与波长有关,以8mm至14mm波段激光较为明显;激光大气传输透过率受地形影响明显,透过率数值随激光出射海拔与地表海拔之差DH的增大而增大,但增速逐渐减慢,因此最终透过率趋于稳定值;短波激光(1.06mm)水平传输透过率随DH的增长存在阈值性,阈值与地表海拔高度有关;激光斜程传输天顶角增大会导致透过率数值减小,减小幅度在天顶角接近0度和90度时变小。
Laser atmospheric transmission is widely used in laser ranging, remote sensing, laser guidance and laser free space communication. The transmission of laser energy before and after transmission determines the maximum incident light intensity of the optical system at the receiving end. Therefore, a comprehensive study of the various factors that affect transmission is essential. Atmospheric radiation transmission calculation software MODTRAN is used to simulate the distribution of gas molecules and aerosols on the laser atmospheric transmission path. The influences of many factors such as topography, altitude, climate conditions and weather changes are taken into consideration to systematically study the changes of laser atmospheric transmission transmission rate analysis. The simulation results show that the atmospheric transmittance of the laser has a wavelength dependence, and the degree of influence by latitude and season is also related to the wavelength. The laser with the wavelength of 8mm to 14mm is more obvious. The transmission of the laser air is greatly affected by the terrain, The value of transmittance increases with the difference of DH and surface elevation DH, but the growth rate slows down gradually, so the final transmittance tends to be stable. The transmission of short wave laser (1.06mm) The growth of DH has a threshold value, and the threshold value is related to the surface altitude. The increase of the zenith angle of the laser slant range will lead to the decrease of the transmittance value, and the decrease will decrease when the zenith angle approaches 0 and 90 degrees.