北斗GBAS着陆系统信号覆盖评估方法

提出了北斗地基增强系统(Ground-based Augmentation Systems, GBAS)的着陆系统(GBAS Landing System, GLS)信号覆盖评估方法, 从卫星对地覆盖及甚高频数据广播电台(VHF Data Broadcast, VDB)信号覆盖两方面进行评估.卫星对地覆盖评估中首先利用网格点分析法和视函数法评估卫星对地覆盖重数及4个覆盖性能指标:覆盖百分比、最大覆盖间隙、平均覆盖间隙及时间平均间隙, 然后从用户角度分析卫星覆盖问题(卫星可见性). VDB信号覆盖评估中, 对电磁波传播过程综合考虑了地球曲率及地形影响.另外, 综合考虑目标机场的卫星可见性及VDB信号覆盖范围, 结合美国联邦航空管理局规定的VDB信号最小覆盖空域, 给出了本文评估方法在VDB选址中的应用.仿真结果表明该方法可以合理确定北斗GLS信号的覆盖情况及VDB位置.

Assessment method of signal effective coverage for BDS-based GBAS landing system

An assessment method of signal coverage is proposed for GBAS(ground-based augmentation system) landing system(GLS) based on BeiDou Navigation Satellite System(BDS). The covering situation is discussed from two aspects: the satellite coverage on earth and the covering of VHF data broadcast (VDB) radio signal. In the first aspect, firstly the grid-point analysis method and visibility function are used to evaluate the cover multiplicity of BDS and other four performance index which are percent coverage, maximum coverage gap, mean coverage gap and time average gap. Then the satellite visibility is analyzed from the user perspective. In the second aspect, the earth curvature and the terrain occlusion are considered into the propagation of electromagnetic wave. In addition, combining with the minimum cover airspace of the VDB signal which is regulated by Federal Aviation Administration, a VDB locating method is proposed based on the proposed assessment method. Experimental results show that the signal coverage of GLS based on BDS and the location of VDB can be determined reasonably by the proposed methods.