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通过双向反射分布函数(BRDF)公式,模拟了空间激光主动照明跟踪中,相同材料、不同粗糙度下卫星表面的BRDF,得出了随着卫星表面材料粗糙度的增加,镜面反射分量越小,漫反射分量越大,双向反射分布散射角越宽,接收到的回波信号对方向的敏感性减小。同时模拟了入射角度对卫星表面BRDF的影响,得出了照明光束小角度入射、接收信号方向与照明光束方向一致时,镜面反射分量的增加增强了反馈信号,当大角度入射时,反馈信号急剧减小。当入射角大于34°时,通过卫星表面BRDF计算得到的最小接收功率,比之前把卫星目标看成朗伯体,通过激光雷达公式计算得到的最小接收功率小。得出了增加照明光束的发射功率为原来的5倍,或者增大接收口径为原来的2.5倍,可以消除大入射角度带来的接收功率的减小,使得系统有4倍的功率余量。
By BRDF formula, the BRDF of the satellite with the same material and different roughness in space laser active illumination tracking is simulated, and the smaller the specular component is with the increase of the roughness of satellite surface material, The larger the diffuse reflection component, the wider the scattering angle of the birefringence distribution, and the less the sensitivity of the received echo signal to the direction. At the same time, the effect of the incident angle on the surface BRDF of the satellite is simulated. When the illumination beam is incident at a small angle and the direction of the received signal is the same as that of the illumination beam, the increase of the specular component enhances the feedback signal. When the angle is large, the feedback signal is abrupt Decrease When the incident angle is greater than 34 °, the minimum received power calculated by the satellite surface BRDF is smaller than the minimum received power calculated by the lidar formula, compared to the satellite target considered Lambertian. The result shows that increasing the illumination power of the illumination beam is 5 times of the original one or increasing the receiving aperture by 2.5 times, which can eliminate the decrease of the received power caused by the large incident angle and make the system have 4 times power headroom.