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将修正的TTHG(two term Henyey-Greenstein)散射相位函数运用到电子散射理论中,并利用小角度近似条件推导出沙尘天气下激光信号脉冲时延和展宽的表达式。研究了脉冲时延、展宽与沙尘能见度之间的关系,以及散射反照率、散射系数和不对称因子等因素对脉冲时延和展宽的影响;分析了不同波长条件下脉冲时延和展宽随传输距离的变化规律。结果表明,在能见度较低的沙尘天气下,脉冲的时延量和展宽量均随传输距离、反照率和散射系数的增大而增大,随大气能见度的增大而减小。尤其是当大气能见度增加至3.5km时,脉冲时延和展宽逐渐趋于一个与激光波长有关的稳定值。随着激光信号波长和沙粒不对称因子的增大,脉冲的时延和展宽呈负指数趋势减小。
The modified two-phase Henyey-Greenstein scattering phase function is applied to the electron scattering theory, and the expression of pulse delay and broadening of the laser signal under dust weather is deduced using the small-angle approximation. The relationship between pulse delay and broadening and the visibility of sand dust was studied. The effects of scattering albedo, scattering coefficient and asymmetry factor on the pulse delay and broadening were studied. The effects of pulse delay and broadening with different wavelength were analyzed Transmission distance changes. The results show that the pulse delay and the amount of broadening increase with the increase of transmission distance, albedo and scattering coefficient in dust weather with low visibility, and decrease with the increase of atmospheric visibility. Especially when the atmospheric visibility increases to 3.5 km, the pulse delay and broadening gradually converge to a stable value related to the laser wavelength. With the increase of laser signal wavelength and sand asymmetry factor, the delay and broadening of the pulse show a negative exponential trend decreasing.