GEO/IGSO混合区域导航星座的设计与优化算法

区域导航星座能够以较低成本和较短时间获得目标区域导航能力，且地球同步轨道是构建非极区区域导航星座的重要轨道类型。提出一种基于GEO（地球静止轨道）和IGSO（倾斜地球同步轨道）的区域导航星座设计方法。基于星下点轨迹特性构造对称星座设计参数和优化参数集，并考虑地球扁率长期摄动影响，计算星座轨道参数。以导航服务区的统计GDOP（几何精度因子）为目标函数，利用差分进化算法构建星座优化模型。以印度IRNSS的7星星座为例，仿真检验了设计和优化算法的正确性，讨论了IRNSS星座优化构型和轨道类型选取。本方法采用的对称星座设计参数少，能够提升GEO/IGSO混合区域导航星座的全局优化效率，为后续非对称星座快速提供最佳星数和构型设计。

Design and optimization algorithm of GEO/IGSO hybrid regional navigation constellation

The regional navigation constellation can provide the navigation ability for the users of the targeted area with the balanced cost and efficiency, and the geosynchronous orbits are some of the important orbit types to construct non-polar regional navigation constellation. A configuration method was proposed for regional navigation constellation based on GEOs (geosynchronous orbits) and IGSOs (inclined geosynchronous orbits). Firstly, a set of SSP (sub-satellite point) involved design parameters were presented and depicted especially for the symmetric constellation. And the long-term perturbations due to the earth's oblateness were induced to recalculate the mean orbital elements of the GEOs and IGSOs and propagate their orbits. Then the statistical GDOP (geometric dilution precision) of the grid points of the specific navigation service area was used as the objective function for the DE (differential evolution) optimization algorithm. Finally, taking the Indian constellation of IRNSS as an example, the presented design and optimization algorithm was verified by the constellation simulation, and various configurations and orbit types of IRNSS constellation were discussed in detail. The results show that for India and surrounding region, the 7-satellite constellation can best consider the navigation performance and construction cost; the elliptical orbit is unable to take into account the navigation performance of the northern and southern hemispheres, which is difficult to expand to global navigation constellation. This method can improve the global optimization efficiency of GEO / IGSO hybrid regional navigation constellation, and provide the number of satellitesand configuration design quickly for the subsequent asymmetric constellation.