| GNSS / MIMU airborne integrated navigation system used for civilian UAV designed in this paper is able to provide more accurate information including attitude angles,heading,angular velocity,acceleration,velocity and position.Compared with traditional inertial devices,the selected MEMS inertial sensors is of light weight,small volume,low cost and power consumption despite its low accuracy,which has been widely used in civil,industry and military field as a result.In recent years,with the rapid development of civilian UAV industry and the requirement of higher navigation precision,the airborne integrated navigation system based on GNSS/MIMU has attracted more and more attention and become the research hotspot in the world.This article consists of three main parts: the design of the airborne integrated navigation system and secondly its implementation,and finally how to improve the system precision.A hardware platform for airborne integrated navigation system based on GNSS/MIMU is designed and made,together with the sensor error characteristics analysis,the sensor calibration method,the noise reduction method of inertial devices,the magnetism anti-interference method and the temperature compensation method accomplished.And this paper presents calculation methods of attitude,azimuth,heading,velocity,position and the expanded Kalman filter.Also an experimental platform on computer has been designed.Experiments proved that this airborne integrated navigation system has a good accuracy,meeting the requirements of civilian UAV work.The main contents are as follows:Firstly,the research importance,current situation and key technologies of the airborne integrated navigation system are introduced,and the basic principles of satellite navigation system,inertial navigation system as well as the integrated navigation system are expaciated.The airborne integrated navigation system platform is built with the core controller STM32F4/STM32F1,the sensors involving RTK system or NEO-M8 N,MAX21000,ADXL362 along with HMC5983 L and the communication equipment CAN bus together with IT card.Secondly,the sensor signal analysis,calibration,interference compensation and temperature compensation are accomplished,the calibration models of accelerometer,gyroscope and electronic compass are established,the inertial sensor random errors and their compensation method are studied,temperature compensation method is designed.Besides,we use MATLAB to process experimental data,obtaining the sensor parameters of calibration,denoise and temperature compensation.Thirdly,the attitude,velocity and position resolving method is designed and implemented.We adopt attitude algorithm based on quaternion,achieving the whole attitude measurement,the MEMS electronic compass detecting heading and MEMS accelerometer detecting carrier tilt,thus real-time correcting the attitude solved from MEMS gyroscopes,effectively solving the attitude detection divergence problem caused by MEMS gyro drift.Also,the speed and position error models are established,using an extended Kalman filter to estimate the optimal attitude,speed and position parameters.Finally,the system composite debugging platform is finished.A system debugging platform based on c# and WPF is designed,including a two-dimensional dial,a three-dimensional model,waveform display and data storage,etc.By system debugging on experimental platform and experimental data processing using MATLAB,the system is proved to be with a higher precision. |
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