Compared with conventional optical satellites, ZY-3(03) has its outstanding advantage in the combination of camera stereo observation and laser altimeter to directly obtain elevation control points, which can provide high-precision data for real three-dimensional China construction, geographic national conditions monitoring, farmland protection, geological disaster prevention, etc. In order to meet the demand of laser altimeter that the divergence angle is less than 0.1mrad, a laser beam expanding system is developed. The optical system with Galileo structure is composed of a negative lens group and a positive lens. Through the adjustment of the lens spacing and centering adjustment, the installation and adjustment of the beam expanding system under normal pressure is completed, and the wave-front error, defocusing and magnification are tested. In order to meet the conditions of vacuum use, vacuum presets are performed by adjusting the spacing between the front and rear lens groups. The vacuum divergence test of the transmitting system is carried out together with the laser. The measured divergence angle of the transmitting system is 0.084mrad, which meet the system design requirements. Subsequently, a mechanical environment test and a thermal vacuum environment test are carried out. The divergence angles before and after the tests, during the high and low temperature conditions are stable and are all less than 0.1mrad.
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