Research On Micro Attitude And Heading Reference System Under High Dynamic Environment

Micro attitude and heading reference system provides accurate and stable attitude and heading information to the carrier through multi-axis inertial sensors,and is widely used in fields that require three-dimensional attitude measurement,such as aircraft and vehicle control.The Micro Electro Mechanical System(MEMS)-based sensors have broad application prospects due to the advantages of small size,low power consumption,and strong impact resistance.However,under high dynamic environment attitude errors will be induced resulting from the MEMS gyroscope's frequency band width,device errors,and the non-exchangeablity of rigid body with rotationt.The attitude algorithm accuracy under high dynamic environment is proportional to the attitude update frequency of the system.Therefore,it is of great significance and engineering value to design an Micro attitude and heading reference system with fast data operation capability and study the error characteristics and attitude update algorithm of MEMS gyroscope in under high dynamic environment.Firstly,in this thesis,Digital Signal Processor(DSP)and Field-Programmable Gate Array(FPGA)are used to design the hardware of the Micro attitude and heading reference system.The DSP is used as the main processor of the system,and the FPGA assists the working mode of the DSP.In this mode,the DSP can focus on attitude solution,which can shorten the update time of the unit attitude,and improve the accuracy of attitude calculation.It lays the hardware foundation for the subsequent research on the attitude update algorithm under high dynamic environment.Secondly,the two main factors from the characteristics of the MEMS gyroscope that resulting in the DC component of the attitude error are analyzed under high dynamic environment.As the MEMS gyroscope's frequency bandwidth is not wide enough,the improved rotation vector algorithm is used for attitude update;an improved calibration method was proposed for the MEMS gyroscope installation error calibration,and the three-axis output accuracy was improved by an order of magnitude.In addition,against G-sensitivity error of MEMS gyroscope,a multi-position turntable calibration scheme is designed,which makes the mean and standard deviation of the MEMS gyroscope sensitive error mode value of rotational angular rate of earth | |e?? from 7.3194o/h,5.6249o/h before compensation to 1.4669o/h,1.2935o/h after compensation,both increasing nearly 5 times.Finally,an angular rotation-based equivalent rotation vector algorithm is adopted as the attitude update algorithm under high dynamic environment,and optimize the cross-product coefficients of the equivalent rotation vector algorithm in a typical cone motion environment.And proposed to use the angular rate and angular increment information in the previous attitude update period to improve the multi-sample algorithm in the current period.The simulation results of cone motion error show that the accuracy of the equivalent rotation vector algorithm doubles as the sub-sample order increasing;Under simulation conditions 1,three sub-orders,it is useless to improve the algorithm accuracy by adding the previous period angular rate information,howover,and the algorithm accuracy is significantly improved by adding the previous period angular increment information;the accuracy of the equivalent rotation vector algorithm gradually decreases as the cone half angle ? and angular rate ? of the cone motion increase,and gradually increases as the attitude update cycle h decreases.