Research On Key Technologies Of The Vehicle Navigation System With The Rotating MEMS IMU

In environments where the Global Navigation Satellite System(GNSS)signals are blocked,the errors in the Inertial Navigation System(INS)can accumulate rapidly,decreasing the accuracy of systems.The observability of INS is closely related to the maneuverability of the vehicle.Besides,errors in INS can still accumulate under the lowdynamic of vehicles,using observation from odometers,laser rangefinders,cameras.The article proposes a method of rotation around a sensitive axis to enhance the maneuverability of the measurement module by utilizing the Inertial Measurement Unit(IMU),where the method includes three rotation schemes which are around the X-axis,Y-axis,and Z-axis respectively.Using the Piece-Wise Constant System(PWCS)observability analysis method to analysis error states in the four navigation systems under two of the worst maneuvers and take non-holonomic constraints(NHC)as observations indeed.Moreover,time plots were generated based on simulation results to intuitively compare the convergence of error states in different systems,and it further validated the theoretical results of observability analysis.Consequently,the analysis indicates that the method can indeed alter the observability of INS and suppress errors accumulation,besides the rotation around the X-axis is the most effective.However,in the vehicle navigation tests using Micro-Electro-Mechanical System(MEMS)IMU modules,the data output showed severe divergence when lacking forward velocity constraints,so it limits the effectiveness showed by rotation systems.Therefore,a forward velocity constraint is added to the observation,and the results of tests showed that the azimuth error and position error of the pure inertial navigation system quickly diverged.The positioning accuracy of the rotational system was significantly better than that of the non-rotational system.Specifically,the system using the scheme of rotating around the X-axis effectively improved the positioning accuracy by 69% in the eastward and 80% in the northward.These results validate the effectiveness of the rotational system in suppressing error accumulation,and the scheme of rotation around the X-axis is the optimal.The success of tests provides important reference for the design of car navigation systems.