Design Of Miniature Vehicle Integrated Positioning System Based On ARM

Vehicle Integrated Position is an indispensable feature in modern cars. It provides the real-time and accurate position for cars with the help of integrated sensors and satellite positioning system, so it has been widely used in the intricate urban transport.In this thesis, in order to improve the positioning accuracy of the Vehicle Integrated Positioning System, an ARM-based miniature Vehicle Integrated Positioning System was designed, which is based on MEMS inertial sensors. What's more, some infusion algorithms were designed to improve the accuracy of the Vehicle Integrated Positioning System.Firstly, the thesis proposed the methods of the Vehicle Integrated Positioning System,and analyzed the basic principles of it, such as the principium of coordinate transformation,the positioning principium of GPS, the positioning principium of MEMS sensors. In this thesis, the integrated positioning principium of MEMS sensors and GPS is proposed.The ADXL345 triaxial accelerometer and the L3G4200D triaxial gyroscope, which are both MEMS inertial sensors, are used in SINS system. To avoid heading drift, the HMC5883L triaxial magnetometer is used to calibrate the drift. In the scheme, the dynamic calibration method is proposed, and it realizes the real-time calibration and improves the usefulness of magnetometer. In the thesis, we give the error models of the MEMS accelerometer and gyroscope, and then we design a filtering methods based on wavelet transform, according this methods we realize to calibrate and filter the raw data, and collect the accurate data.In this thesis, a gradient descent algorithm is used to determine the orientation, and the Kalman filter is used for data fusion. A MEMS sensor unit is designed, and it can measure the accurate orientation of the vehicle. Then, the orientation information is used for calculating the eastward and northward velocity and displacement, which are measured by SINS. Lastly,the Kalman filter method is used for integration of GPS data and SINS data, the accurate positioning data is calculated by this methods. And the experimental result shows that this positioning method can improve the accurate of the system.Finally, the diagrams of hardware and the flow charts of software are demonstrated, and some experiments are used to verify the feasibility of the system. The dynamic calibration experiments verify the feasibility of the dynamic correction algorithm of the magnetometer.The DR algorithm based on the accurate orientation is verified by the experiments. Through the integrated positioning experiments, the Kalman filter algorithm is used for the Vehicle Integrated Positioning System, and the integrated algorithm remove the drawbacks of the single positioning methods. Through the unlock experiment of GPS, it tests the feasibility of the short-term positioning of SINS, and it also reflect the advantage of the integrated positioning methods.