Research On Lunar Surface Geomorphic And Imaging Simulation

With the implementation of the 2nd stage of Chang'e project, lots of simulation experiments are needed for the development and exploitation of Lunar Rover. This thesis aims at the lunar geomorphic simulation and lunar Rover imaging simulation of imaging sensor. The research mainly includes the simulation of lunar surface geomorphic, the implementation of lunar illumination and shadows, the establishment of imaging model of the navigation camera and imaging precision estimation. The main works and innovations are summarized as follows:1. A fast algorithm for simulating the lunar impact craters is presented for the study of lunar geomorphic (including terrain, impact craters, rocks).The algorithm fits simulating simple shapes of lunar craters. Combining using the fractal technique to generate lunar terrain and 3ds max to model rocks, it constructs a geomorphic environment that is similar to reality lunar surface. The simulation test satisfies Lunar Rover's kinematics and dynamic simulation on uneven terrain in the virtual environment.2. The Phong illumination model and Hapke illumination model are realized by GPU. To solve the aliasing problem at shadow rim in traditional algorithms, the thesis proposes an improved method of shadow mapping for the generation of lunar shadow based on CSM algorithm. The algorithm uses PCF algorithm to smooth filtering on shadows based on layered strategy of CSM algorithm. The experimental results demonstrate that it improves aliasing problem at shadow rim of CSM algorithm, which can be used to generate reality lunar surface shadow.3. The relationship between the imaging mechanism of OpenGL and imaging principle of photogrammetry is analyzed. Based on the relationship, the paper sets camera exterior and interior parameters, which are used to simulation navigation camera geometric imaging. The results is proved correctly by precision analysis of simulated images4. Design a system to achieve the simulation of lunar environment and imaging simulation system based on the modularization strategy by combining the lunar geomorphic simulation, the generation of lunar illumination and shadow, imaging simulation modules together.