Abstract: Currently,thedesignofintegrityparametersforthesatellitebasedaugmentationsystemofBDSislackofdegradationparametersforthedifferentialinformation′savailability,andcan′tsatisfytheRTCAprotocol.SothesatellitebasedaugmentationsystemofBDSisnotcompatibletotheotherinternationalsatellitebasedaugmentationsystemofGNSS.TheintegritydegradationparametersofBDSweredesignedaccordingtotheRTCAprotocol,andtheeffectontheuserpositioningwasanalyzedbyusingtheBDSmeasureddata.Basedonthese,theeffectivenessofthisalgorithmwasdemonstrated.Theresultsshowthat,thelocationprecisionoftheaugmentationsystemforBDSreaches113m.However,iftheuserfailedtoreceivesomedifferentialcorrection,thepositioningprecisionreaches144m,decreasesby274%approximately.Inthissituation,byoptimizingpositionmatrixwiththeintegrityparameterstothepastdifferentialmessage,thepositioningprecisionwillincreaseto117m,sotheauthorizedservicewillrecover.

Key words: satellitebasedaugmentationsystem, RadioTechnicalCommissionforAeronauticsprotocol, integrity, degredation, BeiDounavigationsystem;positioning