Solar Radiation Pressure Modeling and Application of BDS Satellites

Solar radiation pressure(SRP)model is the basis of high precise orbit determination and positioning of navigation satellites.At present,it is common to see the study of SRP model of BDS satellites.However,the establishment and application of a comprehensive analytical SRP model based on satellite physical parameters are rare.Different from other conservative forces and non-conservative forces,SRP is closely related to the satellite’s physical parameters and in-orbit state.On the basis of the physical mechanism of solar radiation,BDS satellite physical parameters,in-orbit attitude control mode,and so on,a comprehensive analytical model has been studied in this paper.Based on precise ephemeris and satellite laser ranging(SLR)data,the precision of a comprehensive analytical model has been verified.And the precision of orbit determination is at the decimeter level using this comprehensive analytical SRP model.According to the satellite conservation theorem of angular momentum and change of in-orbit telemetry parameters,the difference between a comprehensive analytical model and the actual in-orbit interference force has been analyzed and calculated.The addition of empirical items on the comprehensive analytical model has been proposed.SLR validations demonstrated that the orbit precision of BDS C08 and C10 can be achieved at 0.078 m and 0.084 m respectively.Compared with using the improved CODE empirical model,precision orbit accuracy of them has increased by 0.021 m and 0.045 m respectively.

Watertight surface reconstruction method for CAD models based on optimal transport

Feature-preserving mesh reconstruction from point clouds is challenging.Implicit methods tend to fit smooth surfaces and cannot be used to reconstruct sharp features.Explicit reconstruction methods are sensitive to noise and only interpolate sharp features when points are distributed on feature lines.We propose a watertight surface reconstruction method based on optimal transport that can accurately reconstruct sharp features often present in CAD models.We formalize the surface reconstruction problem by minimizing the optimal transport cost between the point cloud and the reconstructed surface.The algorithm consists of initialization and refinement steps.In the initialization step,the convex hull of the point cloud is deformed under the guidance of a transport plan to obtain an initial approximate surface.Next,the mesh surface was optimized using operations including vertex relocation and edge collapses/fips to obtain feature-preserving results.Experiments demonstrate that our method can preserve sharp features while being robust to noise and missing data.

Poisson disk sampling through disk packing

Poisson disk sampling is an important problem in computer graphics and has a wide variety of applications in imaging, geometry, rendering, etc. In this paper, we propose a novel Poisson disk sampling algorithm based on disk packing. The key idea uses the observation that a relatively dense disk packing layout naturally satisfies the Poisson disk distribution property that each point is no closer to the others than a specified minimum distance, i.e., the Poisson disk radius. We use this property to propose a relaxation algorithm that achieves a good balance between the random and uniform properties needed for Poisson disk distributions. Our algorithm is easily adapted to image stippling by extending identical disk packing to unequal disks. Experimental results demonstrate the efficacy of our approaches.