Gudimetla V S, Kavaya M J
Department of Electrical and Computer Engineering, Oregon Graduate Institute, PO Box 91000, Portland, Oregon 97291-1000, USA.
Appl Opt. 1999 Oct 20;38(30):6374-82. doi: 10.1364/ao.38.006374.
The theory of special relativity is used to analyze some of the physical phenomena associated with space-based coherent Doppler lidars aimed at Earth and the atmosphere. Two important cases of diffuse scattering and retroreflection by lidar targets are treated. For the case of diffuse scattering, we show that for a coaligned transmitter and receiver on the moving satellite, there is no angle between transmitted and returned radiation. However, the ray that enters the receiver does not correspond to a retroreflected ray by the target. For the retroreflection case there is misalignment between the transmitted ray and the received ray. In addition, the Doppler shift in the frequency and the amount of tip for the receiver aperture when needed are calculated. The error in estimating wind because of the Doppler shift in the frequency due to special relativity effects is examined. The results are then applied to a proposed space-based pulsed coherent Doppler lidar at NASA's Marshall Space Flight Center for wind and aerosol backscatter measurements. The lidar uses an orbiting spacecraft with a pulsed laser source and measures the Doppler shift between the transmitted and the received frequencies to determine the atmospheric wind velocities. We show that the special relativity effects are small for the proposed system.
狭义相对论被用于分析一些与针对地球和大气的天基相干多普勒激光雷达相关的物理现象。处理了激光雷达目标的漫散射和后向反射这两种重要情况。对于漫散射情况，我们表明，对于在移动卫星上共线的发射机和接收机，发射辐射与返回辐射之间不存在角度。然而，进入接收机的光线并非目标的后向反射光线。对于后向反射情况，发射光线与接收光线之间存在不对准。此外，计算了频率中的多普勒频移以及必要时接收机孔径的倾斜量。研究了由于狭义相对论效应导致的频率多普勒频移在估计风时产生的误差。然后将结果应用于美国国家航空航天局马歇尔太空飞行中心提出的用于测量风和大气气溶胶后向散射的天基脉冲相干多普勒激光雷达。该激光雷达使用带有脉冲激光源的轨道航天器，并测量发射频率与接收频率之间的多普勒频移来确定大气风速。我们表明，对于所提出的系统，狭义相对论效应较小。
