BDS/GPS组合导航RAIM可用性分析

采用RINEX数据实验比较了北斗卫星导航系统(BDS)和全球定位系统(GPS)电离层Klobuchar模型在BDS/GPS组合导航中的性能。选择相对较优的电离层模型分析了基于卫星星座类型和卫星类型两种加权情况下，单一北斗、单一GPS与BDS/GPS组合导航系统在非精密进近(NPA)阶段和一类垂直引导进近(APVⅠ)阶段的RAIM可用性。实验表明，在BDS/GPS组合导航中，BDS的Klobuchar模型在中国区域内能修正大量的电离层误差，相比于GPS的Klobuchar电离层模型，电离层延迟修正有0-3.4364 m左右的提高。对于两种加权RAIM算法，在NPA阶段，单一导航RAIM可用性为90%左右，BDS/GPS组合导航的RAIM可用性达到100%。而在APVⅠ阶段，单一导航不具备APVⅠ能力，组合导航APV I阶段RAIM可用性达到100%，具有提供APV I应用的能力。 

Analysis of RAIM Availability for BDS/GPS integrated navigation

The performance of the Klobuchar model of both Beidou satellite navigation system(BDS) ionosphere and Global Position System(GPS) ionosphere are simulated and analyzed based on the RINEX data to choose a more optimal ionosphere model for BDS/GPS integrated navigation. And by using two weighted RAIM algorithms which are satellite constellation type based and satellite type based, different RAIM availabilities are analyzed in the Non-Precision Approach (NPA) phase and Approach Vertical Guidance Ⅰ(APVⅠ) phase of the flight process respectively for the signal BDS navigation, the signal GPS navigation and the BDS/GPS integrated navigation based on the better ionosphere model. The experimental results show that more ionosphere delay can be corrected by applying the Klobuchar model of BDS compared with the Klobuchar model of GPS. The ionosphere delay correction of the BDS model has an improvement of 0 to 3.4364m compared with that of GPS model. For both two weighted RAIM algorithms during the NPA phase, the RAIM availability of the integrated navigation is 100%, and the RAIM availability of either the signal BDS navigation or the signal GPS navigation is approximately 90%. However，for both two weighted RAIM algorithms during the APVⅠphase, the two single constellation navigation methods can not satisfy the APVⅠability, but the RAIM availability of the BDS/GPS integrated navigation reaches 100%, and have the ability to provide the APVⅠapplication.