Based on the simulations of high-orbit applications and all GNSS constellations, the visibility of GNSS in GEO and HEO is analyzed, as well as the influences of inclination and altitude towards the visibility of GPS, GLONASS, BDS and Galileo.In order to deal with the lack of visible satellites, GNSS intermittent failure in short time, an INS-aided scheme is proposed and its availability is verified with analysis of INS short-term error.Furthermore, aimed to reduce dilution of precision (DOP) in high orbit environment, the time differenced carrier phase measurements are preferred.With the comparison of DOP of non-differential and differential GNSS, the advantage of time differenced carrier phase measurements can be confirmed.%通过对高轨航天器轨道及全GNSS星座的模拟, 分析了地球同步轨道和大椭圆轨道环境中GNSS的可见性, 以及高轨航天器轨道倾角与轨道高度对GNSS分系统(GPS, GLONASS, BDS, Galileo)可见性的影响, 提出了配置惯性导航系统的方案来解决短时间内可见星缺失、 GNSS间歇性失效的问题, 并通过对惯导器件短时误差的分析验证方案的可行性;为了改善高轨环境中GNSS几何精度因子, 提出了载波相位时间差分的方案, 对比分析了采用非差和差分GNSS所得几何精度因子, 统计结果显示差分GNSS具有更优的几何精度.
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