Abstract: Aiming at the problem that Beidou satellite system is unable to realize the passive positioning and the accuracy can not meet the higher requirements of the users,the scheme of airborne pseudolites augmented Beidou satellite system was proposed and the key technologies,including geometry,self-fix of airborne pseudolites and system synchronization,were investigated.Airborne pseudolites can not only augment Beidou system to perform passively,but also have the advantages of larger coverage area,better geometry characteristics and so on.