IGPS And CCD Integrated Navigation System Based On Rendezvous Docking Simulating Platform

The main task of this thesis is the research of iGPS/CCD integrated navigation system. The paper discusses the iGPS and Mono-vision measurement system, combined these two measurements systems and proposed integrated navigation algorithm for iGPS and CCD.Firstly,the corner detectding algorithm is discussed according to the practical application.The image edge is detected by using Laplace and Gaussian algorithm, then the corner detection is completed by using Hough transform after the derivation of image edge .The relative position and attitude between the target spacecraft and track spacecraft is derived by two-stage algorithm after getting the corner point.Two-stage algorithm transforms the attitude and position derivation to constrained nonlinear optimization problem. The specific process is divided into two stages: solving the depth of field estimates and calculating the position and orientation. It can be proved that the method of two-stage is a fast globally convergent iterative algorithm.Secondly, GPS measurement system has important application in rendezvous and docking. The iGPS measurement system has the same principle to iGPS measurement system. The process to use iGPS measurement system to determine spacecraft attitude is that: Get the value in the inertial coordinate system and body coordinate system of the feature points to tracking spacecraft .using the algorithm of SVD to solve the tracking spacecraft attitude information. Analyze the simulation of the algorithm of SVD, get the accuracy of the spacecraft attitude.Finally, to design extended Kalman filter to estimate the attitude of the spacecraft to use the error quaternion as the system state variables, using the Taylor expansion to the satellite's attitude motion equation and ignore the order item by the system nature of the linear state equation. To iGPS as observer, use combination rules of the quaternion derived the linear observation equation. then the system can be estimated attitude bias. Design UKF to estimate the system state. First, to use the method of Unscented transformation to the system. Using Chelosky to state error covariance matrix to get sigma points, combined state equation with the observation equation to update the system calculated by the weighted arithmetic average deviation. Then analyze the simulation of the Kalman filter algorithm. Then, using the combination of iGPS and CCD to measure the depth of field to the target spacecraft.Since the accuracy to depth of field is higher than by CCD camera only, thus using the navigation algorithm can improve the accuracy of the position and orientation of rendezvous and docking.