|Prof. Gudrun Klinker
|Weber, Sandro (@no68tap)
This thesis determines a suitable Inertial Measurement Unit (IMU) for the Attitude Determination and Control System (ADCS) for the third satellite of the Munich Orbital Verification Experiment (MOVE). The thesis first explains the requirements and constraints for an IMU. In the context of this work, three IMUs, the BNO055, ICM20948 and LSM9DS1, the LIS3MDL magnetometer, and the BMI088 gyroscope are selected and analyzed. The sensors are implemented using the DOSIS software platform and analyzed using MATLAB. The simulation was implemented using Simulink. The error coefficients of each sensor measurement are initially calculated through the Allan variance. These are then verified through Welch’s power spectral density estimate, simulations, and additional sensor measurements. This estimate is calculated using the pwelch method implemented by Mathworks. The BNO055 was also flown on a high altitude balloon, as well as submitted to a Thermal Vacuum Chamber (TVAC) test. These experiments are then evaluated, and further temperature experiments are performed to characterize the behavior of the sensor in changing temperatures. Finally, two calibration methods, magcal developed by Matlab and the TWOSTEP algorithm, are analyzed through simulated data. The evaluation of the most accurate error coefficients found the BNO055 gyroscope to be the least affected by the white noise compared to the remaining gyroscopes. Among the magnetometers, the LSM9DS1 appears to be the sensor least influenced by the most accurate random walk and white noise term. The temperature experiments determined the BMI088 gyroscope as the sensor least influenced by temperature drift. Among the magnetometers, the BNO055 is the least affected by temperature changes, while the BMI088 appears the most stable amongst the gyroscopes. This concluded that as an overall sensor, the BNO055 IMU is recommended to the ADCS.
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