Digital System for Aircraft Attitude Measurement


Abstract:Aircraft convention defines the attitude parameters in terms of three angles: roll,pitch and heading. These angles are referenced to the local horizontal plane defined bygravity vector. Attitude information for aircraft is obtained by using spinning rotor orring laser gyroscopes. These systems are very precise but they suffer from manyproblems such as high cost, large size and weight and the requirements for elaborate andintricate mechanical structure.These problems can be reduced by the exploitation of the micromachined technology.In this work, an attitude measuring system based on the ADXL202accelerometer, the HMC2003 magnetic sensor and the ADuC812 microcontroller hasbeen designed and implemented. An algorithm for decoding of the ADXL202 outputsignals is described and implemented as software programs written in C-language toperform and display the attitude measurements and a correction method for the errorsintroduced by tilt angles is described.The measuring system operation is examined by the test of the reading’srepeatability and constancy. A good repeatability and constancy with a high degree ofprecision and small amounts of error and dispersion are found from these tests.