Astronomical aided inertial/BeiDou tightly integrated navigation system and navigation method

The invention discloses an astronomical aided inertial/BeiDou tightly integrated navigation system. An inertial element, a Beidou receiver and a star sensor send data into a navigation computer module, and the navigation computer module processes the data and then sends a navigation calculation result to a host machine display module to display. The invention also discloses an astronomical aided inertial/BeiDou tightly integrated navigation method. The method comprises a step of calculating a speed and a position, and using quaternion to describe the pose motion of a carrier, a step of establishing an astronomical aided navigation system state equation, a step of establishing the measurement equation of each sub system according to different working characteristics of each navigation system, and a step of constructing an adaptive Calman filter according to visible stars and the geometrical configuration of the visible stars, and thus correcting the navigation error of an inertial navigation system. According