Satellite Constellation Design for Complex Coverage

Most traditional satellite constellation design methods are associated with a simple zonal or global, continuous or discontinuous coverage connected with a visibility of points on the Earth's surface. A new geometric approach for more complex coverage of a geographic region is proposed. Full and partial coverage of regions is considered. It implies that, at any time, the region is completely or partially within the instantaneous access area of a satellite of the constellation. The key idea of the method is a two-dimensional space application for maps of the satellite constellation and coverage requirements. The space dimensions are right ascension of ascending node and argument of latitude. Visibility requirements of each region can be presented as a polygon and satellite constellation as a uniform moving grid. At any time, at least one grid vertex must belong to the polygon. The optimal configuration of the satellite constellation corresponds to the maximum sparse grid. The method is suitable for continuous and discontinuous coverage. In the last case, a vertex belonging to the polygon should be examined with a revisit time. Examples of continuous coverage for a space communication network and of the United States are considered. Examples of discontinuous coverage are also presented.

卫星星座覆盖性能分析及仿真研究

卫星星座是指由多颗卫星按一定形状构成的可提供一定覆盖性能的系统，可以通过多星协作来完成通讯、气象、导航、定位、侦察、预警、监视等各方面的任务。作为卫星星座的重要性能指标，对地覆盖性能一直广受关注，随着卫星星座应用领域不断扩展，卫星星座的对空覆盖性能日益受到重视。因此本文围绕卫星星座覆盖性能的相关问题进行研究。 卫星轨道动力学是卫星星座覆盖性能分析的基础，也是对卫星星座进行仿真分析的基础。本文在分析轨道动力学原理的基础上，推导了J2000坐标系下卫星运动方程、星下点计算方程，完成了仿真算法实现，用STK验证，结果吻合较好，为星座覆盖性能仿真分析打下了基础。 本文系统地研究了星座对地覆盖分析中的解析法和数值仿真法（包括视函数法和地心角法），在此基础上提出了载荷与星下点重合和偏离两种情况下卫星对地瞬时覆盖面积的解析方法。根据地心角法原理，结合卫星的载荷特性，推导了卫星对空间球面的覆盖判据，给出了卫星星座对空间的覆盖分析方法。 为了对星座的覆盖性能进行定量评估，本文系统地提出了一组覆盖性能指标，包括覆盖重数、覆盖时间、覆盖时间百分比、覆盖面积百分比、间隙时间百分比、间隙面积百分比的最大、最小和平均值等，给出了各项性能指标的意义与计算方法，用于评价其覆盖品质。 在上述工作的基础上，本文设计并实现了星座覆盖性能仿真系统，通过对典型星座的覆盖性能进行仿真分析，明确了影响星座对地覆盖性能的因素，验证了对地和对空间覆盖分析方法及指标的合理性，得出的结论可以用于星座设计和星座优化等，此外，对空间应用设计也有一定的参考价值。