Study On Geosynchronous Orbit Satellite Optical Characteristics Based On Triangular Panel Method

In the study of optical properties of geosynchronous orbit satellites, the satellite's apparent magnitude has great significance in designing the detection system and planning detection tasks. In order to achieve an accurate calculations of optical characteristics of geosynchronous orbit satellites, the thesis presents a triangular panel method to calculate the effective reflective area, and establishes the computational model of apparent magnitude. In order to validate the model, the thesis selects a geosynchronous orbit satellite FY-2 as the research object, simulates the curves of FY-2 effective reflective area and apparent magnitude vs. time, and tracks the satellite by using the double photoelectric tracking system. The main contents of the full text are as follows:(1) The thesis describes the research background of optical properties of the target, as well as the research in photoelectric tracking system, and provides an overview and introduction of the development trend.(2) The thesis describes the basic concepts of Photometry and the reflective properties of the target surface. Then, the thesis deduces an apparent magnitude computational model and a triangular panel method to calculate the effective reflective area. By using the triangular panel method, the thesis calculates four common geometry parameters (cubes, cylinders, cones and spheres) and analyses its performance from the perspective of correctness, accuracy and complexity. The results show that:to astringe the magnitude model, the surface segment number of triangular panel method was less than 20%, compared with the mesh-creation method. The difference in calculating the effective reflective area between triangular panel method and theoretical formula is up to10-3, the complexity of the model and the time spent are reduced by using the triangular panel method.(3) The thesis defines the spatial coordinate system, using the geosynchronous orbit satellite FY-2 as a simulating model, then, calculating its accurate optical characteristics and considering the impact of the shadow and attitude changes in optical properties of the satellite. The results show that:In place of the eastern (120.1°E,30.2°E), from 19:00 to 20:00 on May 1,2013, FY-2 with 12.42 and 13.67 magnitudes was observed by using the double photoelectric tracking system. In one operating cycle, the running time of satellite in shadow is about 2280s. Compared to rolling and yawing motion, the pitching motion has a greater impact on the satellite's optical characteristics under the same circumstances.(4) The thesis uses a double photoelectric tracking system conduct an experiment of FY-2 and the star, then, the thesis deduces a Lognormal model between light intensity and apparent magnitude and uses this model to calculate the FY-2 satellite apparent magnitude. The results show that:the Lognormal model is superior to Lorentz model?Allometric model and ExpGrow model in calculating light intensity and apparent magnitude. The results of apparent magnitude by using triangular panel method are consistent with experimental data, further verifying reliability of the triangular panel method.