Tight Intrgration Navigation System For Land Vehicle

The navigation system for vechile must give continuous, stable and high-accuracy positioning results when need to drive for a long time and distance. GPS (Global Positioning system) can't work when lock of the visible satellites. The errors of the Strapdown Inertial Navigation (SINS) build by low-cost MEMS inertial measuring unit (IMU) accumulate very quickly.So it can't work well for a long time.The problem of lack of visible satellites can be solved by MEMS/GPS Tight Integration Navigation System,but it can't correct the errors of the attitude angle. The SINS build by low-cost MEMS IMU has very big errors, so the errors of the attitude angle grow very fast, which affect the accuracy of the Tight Integration System,even leads to the corruption of the filter.The Chapter II is mainly about the principle and error characteristics of GPS and SINS,as well as the the characteristics of MEMS IMU which development rapidly in recent years.Through comparision of the two navigation system by simulation, we demonstrate the the advantages, disadvantages and the complementary of the two system. In Chapter III, we talk about the the principle of the Extended Kalman Filter (EKF), and the concept of integration navigation system's two structures: open loop and closed loop. We designed two controlled trials, the open loop compared with the closed loop, and the other is the number of visible satellites are respectively 3 and 4. The result of the controlled trials demonstrated that the cloed loop structure has a better performance and the Tight Integration can still work for a well when the number of visible satellites is less than four. According to the characteristics of the vehicle, we proposed a MEMS/GPS Tight Integration Navigation System's attitude angle's feedback correction algorithm in Chapter IV. Using the measurements of velocities output by Tight Integration,we can calculate the head angle and pitch angle,then build the attitude angle's measurement equation and take the simplified Sage-Husa adaptive filtering algorithm to filter. We also designed an experiment to verify the performance of the algorithm,the results demonstrated that this algorithm has an higher precision than the traditional algorithms and keep stable for a very long time. In Chapter V, we provided the details of the MEMS/GPS Tight Integration Navigation Simulation System; include the structure and principle of the system,as well as SINS simulation module, GPS module and Kalman filter module. The system was developed by Matlab's M language which has high efficiency and strong portability.This part of work laid a foundation for subsequent hardware implementation.The MEMS/GPS Tight Integration Simulation System was proven to be effective and accurate.The attitude angle's feedback correction algorithm was demonstrated effective and feasible though the simulation system. It means some key problems of the practical application of the future have been solved.