考虑地形影响的卫星导航性能评估方法

摘要

研究准确评估导航性能,针对地形因素会影响导航卫星的可见性,为了准确评估地形复杂地区对卫星导航的性能的影响,在仿真模型中引入地形影响因素.利用可视域分析理论完善了卫星可见性的判断依据,给出了考虑地形影响时可见卫星颗数和精度因子的分析模型,做为指标对卫星导航性能进行评估.结合机场终端区数字高程模型、卫星星历、航图等数据,对民用航空进近航路上导航卫星的可见性和精度因子建立的模型在MATLAB软件上进行了仿真和定量分析.仿真结果证明,方法可以检测出由地形影响导致的可见卫星减少、精度因子增大、导航性能下降,得出更准确的评估结果,避免潜在的安全风险.%Terrain can affect the visibility of navigation satellites, so that terrain effects should be taken account into performance simulation model to evaluate satellite navigation performance in complicated terrain areas more accurately. The criterion of satellite visibility was given based on visibility analysis theory, and analyzing models of satellite visibility and dilution of precision ( DOP) considering terrain masking and important indexes of navigation performance are demonstrated. Depending on the information of airports Digital Elevation Model, satellite almanac, and flight trajectory, satellite visibility and DOP were simulated and analyzed by using this method with MATLAB. The results demonstrate that this method can detecte degraded number of visible satellites, increase DOP and decrease precision of navigation caused by terrain impact, therefore the result is more accurate and can avoid potential problems.