Research On Accuracy And Integrity Enhancement Of CAT ?/? GBAS

Ground based augmentation system(GBAS),as an important choice for the next generation precision approach landing system,can make up for the inherent shortcomings of instrument landing system(ILS)and provide airborne users with higher standards of required navigation performance(RNP).In the long run,GBAS will serve as a single navigation system for Category I ~ Category III Precision Approach(CAT I ~ CAT III),which can provide guidance for precision approach landings of aircraft,as well as provide enhancements to a certain airspace in the terminal area.This paper focuses on the RNP four performance parameter index requirements,taking the minimum performance standards promulgated by the International Civil Aviation Organization(ICAO)and American Aeronautical Radio Technical Committee(RTCA)as references,by examining the GBAS accuracy error model and system integrity detection research and adopt corresponding methods to finally achieve the enhancement of accuracy and integrity of CAT ?/? GBAS.At the same time,the usability assessment method of CAT ?/? GBAS in BDS environment is given.The main works of this thesis are as follows:(1)In order to achieve the accuracy enhancement of CAT ?/? GBAS,various factors affecting the positioning accuracy of GBAS are studied.From the perspective of improving the accuracy of pseudorange,the influence of the ionospheric space-time gradient delay error and multipath error on the Hatch filter error is studied,and then the adaptive optimal smoothing time is derived to minimize the system error.The GBAS positioning error simulation in both static and dynamic environments is used to verify the enhancement of GBAS accuracy.(2)In order to enhance the integrity of CAT ?/? GBAS,research was conducted from two aspects: ground integrity testing and airborne integrity testing.Ground integrity testing focuses on the B values and s values of integrity parameters that reflect whether the reference receiver station is normal.Aiming at the shortcomings of B-value multi-reference consistency check(MRCC),a fault detection method based on Hilbert-Huang(HHT)CAT ?/? GBAS reference receiver station was implemented to enhance the integrity of the ground end of GBAS.Airborne integrity testing is performed by studying the integrity risk allocation of CAT ?/? GBAS,four pseudorange bias models that affect GBAS protection levels,and position domain errors caused by the ionosphere.Calculation of protection levels.Experimental simulations verify the integrity enhancement of CAT ?/? GBAS.(3)Based on the enhancement of the accuracy and integrity of CAT ?/? GBAS,according to the usability research process of LAAS,a method for evaluating the availability of CAT ?/? GBAS in the BDS environment is given.The three key factors of the potential location domain errors of the CAT ?/? GBAS,the given satellite geometry,and the configuration of the reference receiver type are studied.The relationship between availability and related parameters is analyzed through simulation.This thesis mainly focuses on the accuracy and integrity of CAT ?/? GBAS.While implementing the enhancement scheme,a method for assessing the usability of CAT ?/? based on BDS is given.The research results are for the follow-up CAT ?/? GBAS airworthiness Sexual research provides corresponding theoretical references.