Highly Dynamic GPS Compass Design And Implementation

The GPS compass is a device that provides the heading information of vehicle by using the satellite signal.The GPS compass is not affected by the distribution of the magnetic field of Earth and there is no cumulative error when it compared with the magnetic compass and the gyrocompass.Therefore,the GPS compass has good performance and relatively low cost,which presents a huge prospect for applications in the fields of land,sea and air.However,in real application,the GPS would present signal loses-lock,the output time-delay and data skipping phenomenon when the vehicle is moving quickly.Meanwhile,the output frequency of GPS compass is low that is usually around 1 Hz or 5 Hz.Based on this,this paper mainly studies the GPS compass system in high dynamic environment,which is designed by the combination of dual GPS and MEMS(Micro-Electro-Mechanical System).The MEMS inertial navigation system has the characteristics of high dynamic performance and rapid response in a short time,which could make up the shortcoming of low GPS update frequency and realize the continuous and accurate reflection of the navigation information of the vehicle during the motion of the carrier.At the same time,the dual GPS and MEMS combination realizes the stable heading output of the system for long-term navigation,and can ensure the correct output of the heading in the case of poor or high dynamic GPS signals.Based on this,the main work of this paper is as follows:First of all,the design of the GPS compass system hardware platform.Develop the expected target to select inertial sensor,GPS board;design hardware circuit;choose FPGA and DSP dual-core system as the system architecture,FPGA performs sensor data collection work,DSP solves navigation work,customizes kernel for system task Scheduling and so on.Secondly,the MEMS sensor error model is established and error compensation is performed.Analyze the error type of MEMS inertial sensor,establish its error calibration model,and perform indoor calibration.At the same time,the ellipsoid error compensation for geomagnetism.Install different antenna distances,analyze the correlation between the heading of the dual GPS board output and the baseline distance,and get the best GPS antenna installation plan.Thirdly,design a data fusion algorithm for GPS compasses under high dynamic conditions.The navigation information coordinate system is completed,and the synchronous processing method of design information fusion has been designed with Kalman filtering.When designing the fusion algorithm of dual GPS information and INS information,the effectiveness of GPS information is judged by the algorithm.When the GPS information is valid,the data is updated and output.When the GPS heading information is unavailable,the INS is used to predict the output.Finally,the experimental verification of the highly dynamic GPS compass system is carried out.Static tests and dynamic tests were carried out separately,and the test results were analyzed to improve the system.The designed high-dynamic GPS compass system has an update frequency of 100 Hz.The heading accuracy is kept within 2.5° in the case of on-board and on-board conditions and the navigation information is normally output within 3 minutes when the GPS information is not available.