The Design And Realization Of A Uav Attitude And Heading Reference System

At present, some military great powers especially the U.S.A lead the research work of the Unmanned Aerial Vehicle (UAV). China is also in the process of studying and researching the new techniques of the UAV.This paper mainly focuses on the working principles and system design of the Attitude Heading Reference System (AHRS) of a certain UAV. The system features with low cost, small bulk and upper precision. The task refers to many kinds of techniques, and has a lot of workload and difficulties, which includes of researching the signal arithmetic, measuring and compensating the inertial instruments, filtering the signal values, designing the whole AHRS and debugging the system.The paper introduces the developing progress and the status quo of the UAV, explains the key techniques of the AHRS. It discusses the coordinates and basic equations of the AHRS, compares the characters of the different modification arithmetic, and simulates the quaternion theory. The working principles and the characters of the inertial instruments, which include of gyro, accelerometer, magnetic compass and inclinometer are analyzed amply, many experiments are practiced to capture the real data, and utilizes the Matlab tools to compensate the instruments' error. Then the paper analyzes the filtering technique and applies the Kalman filtering theory to the practical signal measurement in order to improve the precision of the system. The paper introduces the whole design method, the hardware and the software design process and the debugging process. The conclusion is given at last.Combined with the practical work, the paper suggests a compensated gravity method and a modularized former channel design method, and gives a conclusion of the applicability of the inclinometer. The AHRS adopts a new design method that uses the Micro Electron Mechanical Systems (MEMS) based inertial instruments to measure the signals and the TMS320VC33 as the system DSP chip. This method extends the design thought of the AHRS, and popularizes the application of the MEMS inertial instruments of the small bulk UAV.