Research On Navigation Reference System With Multi Sensors Fusion Based On μC/OS-Ⅱ

The main task of the thesis was to design and accomplish a navigation attitudereference system which was based on embedded real time operating system(μC/OS-Ⅱ). This system can be used on Miniature Unmanned Helicopter(MUH).Miniature Unmanned Helicopter(MUH) has an advantage of small shape, a light weight, good flexibility, easy to achieve hover and ability to fly in the low areas. Not only in the military field but also in the civilian field does MUAV have a wide application foreground. When the MUAV is carrying out a task in the sky, it needs real time information of both attitude and altitude, so as to adjust attitude of the MUAV in the sky, to correct its flight route, to solve the navigation problems of the flight. Compared with flat roof system, strapdown system's hardware is much simpler, it has a lower manufacturing cost and higher credibility. Therefore, it became our first choice. Meanwhile it must be recognized that using strapdown system the conversation problem between the helicopter reference frame and roof reference frame should be solved. Its software arithmetic is more complex and it needs the technology of sensor's abundance to process the information.Aiming at those problems, the thesis adopted ARM company's 44B0X as the whole hardware flat roof, the system used magnetism sensor, accelerometers and gyros to collect the attitude information of the helicopter and temperature, pressure sensors to collect the altitude information. Whole software module was built on μC/OS-Ⅱ, which is an Embedded real-time operating system. In our system, μC/OS-Ⅱ is transplanted into 44BOX successively. Among the proceeding application, the thesis made some better improvements in μC/OS-Ⅱ's timer interruption module.In order to reduce the influence of the environmental errors and promote the stability of the collecting data, an Extended Kalman Filter was constructed to fuse allthe attitude sensors, and a discrete Kalman Filter to process the altitude information. At last we got the testing result of our system through three-axes simulation rotating platform.