Circuit Design Of Sensors And Implementers For Pico-Satellite Attitude Determination And Control System

Attitude Determination and Control system is an important part of the satellite platform, which plays an important role for the successful completion of the satellite space missions.Attitude control system is composed of Sensors, Controllers and Implementers. This paper is mainly about research of the MEMS Gyroscope sensors, Triaxial Magnetometer, Bias Momentum Wheel and Magnetic Torquer.In this paper the problems for the existing system are based on, the electrical properties of the hardware are analyzed and through the results of the analysis the corresponding system are designed to improve its performance.Single integrated chip ADN8831-PID temperature controlor is used in the MEMS gyroscope circuit design to achieve high stability temperature control, the test shows that the temperature control system could work in the environment temperature range of [-5℃,35℃]. In this range the temperature stability of the system could achieve±0.2℃even the temperature of environment are volatile acutely. In this paper, the temperature control system are applied on MEMS gyro in [-5℃,35℃] for zero drift test, the Allan variance theory is used to stochastic modeling of MEMS gyroscope, the result of temperature experiments show that Bias instability and Rate Random Walk of MEMS gyroscope are enhanced, in particular Rate Random Walk has been greatly improved.In the Triaxial Magnetometer circuit design, the impact of bias of the Magnetic Sensors is eliminated. To avoid the interference of industrial frequency, the AD with comb filter is chosen and the mean arithmetic is used to filter the signal to optimize the three Axis magnetometer output, this improves the precision of the system. The test results show that the precision of the magnetometer we designed could achieve the order of 10-8 Tesla.By analyzing the parameters of Bias Momentum Wheel, the circuit is designed to test its speed and Current. The performance of momentum wheel is got by the current and speed test under different voltages. The reliability of momentum wheel in space could be improved by the result of the tests. The test results show that in the conditions of 9V power supply, the speed stability, acceleration/deceleration performance and power consumption are more reasonable.The current detection circuits for Magnetic Torquer are compared and the circuit which has better performance is chosen. Analyze the threshold to determine the switch state under different temperatures, the result of tests show that the experimental data accord with theoretical Analysis.This paper refers some methods about hardware design of Attitude Determination and Control system, we hope the work done in this paper could be the foundation of the optimization for the hardware design system in future.