Research On Embedded Heading And Attitude Reference System Based On ARM

It's well-known that heading and attitude of vehicles are very important parameters in the navigation system of UAV (Unmanned Aerial Vehicle). It's the pre-requisite condition of UAV holding anticipant attitude and aviating steadily in the air. With the rapid development of embedded system and the appearance of newly and high-performed components, this paper puts forward and researches a kind of Attitude and Heading Reference System (AHRS) which consists of high-performanced ARM embedded microprocessor and embedded real-time operating system.Firstly, in this paper, the basic theories and operational principles of AHRS are introduced, including definition of usually coordinates in inertia system, Euler angles definition and calculation of attitude matrix.Secondly, we focus on the hardware and software design of AHRS based on ARM. In the hardware design, we present the overall plan of hardware designing and discuss every function module in detail. Software is developed by uC/OS-â…¡ as embedded RTOS. On the basis of the general software chart of system, we describe the hardware drivers, transplant of the operating system and the division of tasks.Lastly, we analyze the reasons of magnetic heading's error and the compensation methods. What's more, we experiment to validate the ellipse hypothesis compensation method.Research proves that the AHRS compared with general attitude and heading measurement system is small size, low cost, high real time and so on. AHRS based on S3C44B0X microprocessor and uC/OS-â…¡ RTOS is composed of 3-axis micro accelerometers, 3-axis micro rate gyros and 3-axis Magnetoresistive sensors. The system is of great practical value.