Application Research And Simulation Of Multi-Satellites Integrated Navigation For PBN

At present there are many weaknesses in traditional navigation, such as limited flight route, limited coverage, high equipment maintenance cost. These weaknesses restrict it to realize PBN flight and free fly. Considering those problems, the International Civil Aviation Organization(ICAO) proposes to develop Global Navigation Satellite System(GNSS) as primary navigation source in future. By the end of December 2012, BDS can provide navigation and positioning services for the asian-pacific region, and its global navigation and positioning function are actively developed. But among the world's top four GNSS satellite navigation system, including GPS and BDS, only GPS can provide global navigation and positioning services. For the poor visibility and poor geometrical configuration of single constellation navigation system, it is significant to analyze the performance of GPS/BDS integrated system combined with PBN approach requirements, in order to ensure the integrity availability of integrated system and flight safety.Based on the researches on satellite navigation and receiver autonomous integrity monitoring principle, the application of GPS/BDS integrated navigation during PBN approach is researched. Firstly, the basic performances of integrated navigation system are analyzed, including space-time unified characteristics, satellites' visibility, geometrical configuration and single or double frequency ionospheric model, based-on the terrain data, satellite ephemeris data and observation data. Secondly, considering the availability prediction of receiver autonomous integrity monitoring algorithm before flight, the principle of traditional receiver autonomous integrity monitoring algorithm(RAIM) and advanced receiver autonomous integrity monitoring algorithm(ARAIM) are compared and analyzed. Finally, according to system availability standards presented by ICAO, the availability of RAIM and ARAIM are compared during NPA, APV I, LPV-200 phases,and the availability of ARAIM before and after the optimization of integrity hazard allocation are analyzed. Experimental results show that the satellites' visibility and constellation's geometry configuration of integrated BDS/GPS navigation system is better than that of single navigation system. More ionosphere delay can be corrected by Klobuchar model of BDS, compared with that of Klobuchar model of GPS in Chinese region. More ionosphere delay are corrected by dual-frequency ionosphere model than that of single Klobuchar model. RAIM algorithm only satisfies the NPA and APV I approach requirements, but ARAIM algorithm meets both NPA, APV I and LPV-200 approach requirements, and its availability is higher than that of RAIM. The the availability of optimized ARAIM algorithm under the condition of VPL below 25 m is increased for integrated BDS/GPS navigation.