Research Of GPS Integrity Augmentation

Integrity performance is the key to assure the stringent safety requirementS of flight, andto take GPS as the sole-means of civil aviation navigation. This paper focuses on the three GPSintegrity monitoring techniques, including Receiver Autonomeus Integrity Monitoring (RAIM),Wide Area Augmentation System (WAAS) Integrity Monitoring and Local Area AugmentationSystem (LAAS) Integrity Monitoring. The prob1ems relating to these three techniques, such assystem designation, algorithms impIementation, performance assurance of satellite geometry,availability and so on, are studied systematicallyThe widely used performance assurance aIgorithm of satellite geometry for RAIM isinvestigated in detail, then a new Horizontal Protection LeveI (HPL) algorithm that takesaccount into both the APR and noise influence is proposed. This a1gorithm has betterpefformance assurance in case of non-precision approach phase of flight. The availability ofRAIM is anaIyZed extensiveIy, especially which perfbrmed in chin' in the conditions ofdifferent GPS const6llations, augmenting with a barometric a1timeteF, augmenting withgeostationaIy satellites, with or no SA and so on. Some valuable conclusion is achieved. Formultiple faiIures of WAAS RAIM, an avaiIability analysis method, which is, based theprobability of missed detection and to enlaree variances is proposed, and some results areobtained by simulation.An integrated, mu1tiplc-tire verification WAAS integrity monitoring architecture isdesigOed, and the verification algorithms of User DifferentiaI Range Error (UDRE) and GridIonospheric Vertical Error (GlVE) is designed in detail. Some good conclusion is achieved bysimulation. The variance prOPag8tion method to datermine the intOgrity in user position-domainis proposed, and this method can improve availability than threshold transfetring according tosimulation. Avalability anaIysis of WAAS augmenting with 3 g6ostationary sateIlites ispedermed in china are4 and resultS show it cannot s8tisfy the requirements.A LAAS integrity monitoring architecture is designed, and the ca1culating modeI basedthe combination of ground and user is deduced. The method of faults excIusion of multipleground reference stations in pseudorang6-domain is anaIyzed, and the rule of maximum Bvalue exclusion is designed. This rule can reduce probabiIity of excluding all references andassurmce continuity The equivalent betWeen linear combination 8 value and Ieast squaresresidual is deduced, and the method of fauIts excIusion of multiP1e guund reference 5tationsaccording to least squares residual is pointed out. Based on multiple hypOthesis fault4olerantestimation, the method of faultS excIusion of muItiple gnund reference stations in userposition-domain is proPOsed. This method can improve avaiIabiIity through anaIysis.