Technique Research On BD Satellite GBAS Integrity Monitoring

The development and application of the Performance Based Navigation(PBN) is one of the main research contents of global navigation technology. PBN is a new concept of technology which was proposed by International Civil Aviation Organization(ICAO) to combine area navigation and Required Navigation Performance together. Based on Global Navigation Satellite System(GNSS) and airborne equipment, the new navigation technology can provide more accurate and safe flight line and more efficient air traffic control mode, and reduce the investment on ground navigation equipment. Based on the framework of ICAO,Civil Aviation Administration of China(CAAC) is to combine Beidou System and Ground Based Augmentation System(GBAS) together and promote the development in Chinese aviation field.Based on precision approach and landing phase of aircrafts, GBAS can provide high precision position information and guarantee system avalibility. The reliability level of system is measured by the integrity of system. Integrity monitoring technique is the ensurance of precision approach and landing and high accuracy positioning. The paper focuses on the research of the integrity monitoring technique of ground reference stations and the whole system in the GBAS.Firstly, the paper introduces the profile of the Beidou navigation system, the operating principle of local area differential positioning and the limitation of traditional Instrument Landing System(ILS).Then we propose the concept of GBAS, and illustrate the required performance indicators of precision approach in the system.Secondly, the paper gives a description of the framework of GBAS, including the design of ground reference stations, the indicators of reference receivers and the parameters of Very High Frequency link broadcast device. Then, we introduce GBAS ground reference stations system and make an experiment to test the related processing algorithms, such as local pseudo-range differential correction computation, baseline weighted navigation solution and how users utilize navigation system error to build model. At last, we explain integritymonitoring system algorithm of GBAS in detail, including reference receivers conformity and the research of user Vertical Protection Level.In the end, the paper propose configuration requirements of simulation experiment, and obtains a simulation conclusion of GBAS integrity monitoring by utilizing the GBAS data we collected before. Then we analyze the impact of visible satellites status on GBAS integrity monitoring as well as precision approach and landing.