Study on Attitude Measurement Errors of the Infrared Earth Sensor Caused by Motor Speed Asymmetry

Attitude measurement errors of the double cone scanning infrared earth sensor caused by brushless DC motor speed asymmetry was researched.The speed model of the brushless DC motor was developed.According to the motor’s speed model and the characteristics of the earth signal obtained by the infrared earth sensor,the mathematical model of attitude measurement errors caused by motor speed asymmetry was deduced.The mathematical model can be used to calculate spacecraft’s attitude measurement errors to realize the spacecraft measurement data’s real-time correction.The result from above shows that the precision for the spacecraft attitude measurement and control can be assured.