Method Research On Degree Of Observability Analysis And Precision Assessment Of SINS/GPS Integrated Navigation System

This thesis is constituted mainly by three phases with regard to the study of SINS/GPS Integrated Navigation System, its degree of observability analysis and the precision assessment, which are listed as below.According to analysing the working principles and its error propagation properties of Strapdown Inertial Navigation System (SINS) and Global Positioning System (GPS), the SINS/GPS Integrated Navigation System error state equations is established and its relevant Kalman filter is designed. For the sake of verifying the former theoretical study, a flight track generator which's based on integral algorithm is developped, which simulates the aircraft's position, velocity and attitude information in five different maneuver modes and outputs the Inertial Measurement Unit(IMU)'s sensitivity, specific force and absolute angular velocity. Finally, simulation validates the error model's effectiveness.Based on the former production, the established system is transformed into Piece-Wise Constant System (PWCS), and its degree of observability is computed by means of Singular Value Decomposition (SVD), which takes the simulated navigation data as input viaribles. As aircraft flights in different maneuver mode, its observability changes correspondingly. So it's helpful to find out the optimum maneuver mode to improve the degree of observability, so as to forecast the estimation effcet of Kalman filter. Meanwhile, a normalization method of coefficient matrix is presented and the observed parmeters are abbreviated, which simplifies the analysis procedure and is testified by simulation. Futhermore, the degree of observability is analyzed by matrix V, which simplifies the analysis more. Finally , the reason of singularity phenomenon is presented and the deficiency of SVD on analytic sort is discussed.As the integrated navigation system is established, a fixed-interval smoother (FIS) and a fixed-point smoother (FPS) are designed separately, which are used to assess the navigation accuracy. Simulations in different circumstances are given to prove the validity of both methods. After comparison, it shows that they have different advantages and could be applied to different circumstances. After accomplished the analysis on degree of observability and accuracy assessment of SINS/GPS integrated navigation system, the latter's simulation supports the validity of the former's.