Key Technology Research On Integrated Navigation System Based On MIMU/GPS/Electronic Compass

The high-tech features of modern wars indicate that the precision of ammunition strike hasbecome the inevitable trend of future high-tech weapons development. A large number ofnavigation-guided weapons are urgently needed in the complex battlefield of strong technicalconfrontation. Meanwhile, the integrated navigation systems with low cost, high reliabilityand moderate precision are also urgently needed in the intelligent traffic management systemand other civilian areas. The above urgent demands prompt the navigation system to developin the direction of low-cost, miniaturization and multi-combination. Under this background, amethod of MIMU/GPS/electronic compass integrated navigation system was proposed anddesigned. Take DSP+FPGA as the hardware carrier of integrated navigation system,combination the systems optimally and complementary advantages by means of federationKalman filtering algorithm, constituting the integrated navigation system with the advantagesof low power, low cost, high reliability , and multi-degree of redundancy.First of all, on the basis of analyzing the working principles of MIMU, GPS andelectronic compass, the overall program was designed; according to the analysis of errormechanisms on MIMU, GPS and electronic compass respectively, correspondingmathematical models were built. And in view of the error model for electronic compass, afield fast calibration and compensation method for electronic compass based on ellipsoidfitting was proposed, and the correctness and effectiveness of the method were verified by theturntable test.Then, the MIMU/GPS/electronic compass federal Kalman filter was set up on thecondition of the unified coordinate system. An initial alignment method based on Kalmanfilter was brought up; which introduced electronic compass to assist the attitude determination to complete the system coarse alignment, and then use the Kalman filtering algorithm for finealignment to further improve the system precision of the filter. Aiming at the practicalapplication requirements of high precision and high fault-tolerance, the non-reset federatedfilter consisting of position, velocity, and attitude sub-filter was designed. Each sub-filterworks independently without the feedback of reset, bringing the highest level of faulttolerance.Finally, the integrated navigation system hardware circuit based on DSP + FPGA wasconstructed. Use the abundant logic resources of FPGA for accurate timing control and 1PPSsignal GPS receiver output as the time synchronization label to realize the synchronousacquisition of MIMU, GPS and electronic compass. Take DSP as the information integrationcenter, completing the posture position solution, filtering algorithm and communication withPC in real-time. They cooperate harmoniously with each other and accomplish the task ofnavigation solution together. Simulation experiment and field vehicle experiment shows thatMIMU/GPS/electronic compass integrated navigation system meets the application needs.The system has the characteristics such as s low cost, mall size, high precision and high faulttolerance, which lay a good foundation for the further experimental study.