| The purpose of this project, named Spacecraft Attitude Control Program (SACP), was to design and develop a simulation program for spacecraft attitude determination and control; this application program would serve the purpose of a test bed for research in the field of attitude control. The project involved several phases of work that included (a) identifying the various mathematical models that needed to be incorporated into the computer program, (b) source-coding these models into a general purpose computer language, and (c) integrating this source code with a dynamic simulation software.; Several literature materials were used in identifying the mathematical models that needed to be incorporated into the program. The program now contains extensive mathematical models describing spacecraft kinematics and dynamics, spacecraft attitude determination algorithms, celestial mechanics, sensor outputs, and sensor observation models. Although literature on mathematical models related to spacecraft attitude dynamics and control is extensive, it was found that they (the models as they are in the literature) could not be used directly towards source-coding into the application program. Extensive modifications were made to the already existing mathematical models and several other models were independently developed, and a set of models that was representative of the spacecraft attitude dynamics scenario was obtained.; Once the models were identified, coding was undertaken. Emphasis was placed on simplicity, modularity, reusability, and portability of the code. The choice of the high-level computer language to be used for coding was C.; Finally, the code was integrated with an existing dynamic simulation software package called MATLAB{dollar}spcircler{dollar}/SIMULINK{dollar}sp{lcub}rm TM{rcub}{dollar}. This package provided the program with dynamic simulation capabilities in addition to good user interface. By using MATLAB/SIMULINK, the mathematical models that were in the form of C code were organized into a library of reusable objects that could be used within the environment of MATLAB/SIMULINK to simulate spacecraft attitude control systems. |
