Design Of The Coarse Aiming Feedback Unit In Laser Satellite Communication And Analog Fault Diagnosis

As Science and technology is advancing by leads and bounds because of its hightransmission speed and high security, space laser communication is becoming a hotspot.In order to complete the aiming, acquisition, tracking behavior in space lasercommunication the sensor in the control system is needed to provide displacementmeasurement with high precision. Photoelectric encoder with advantages of highprecision and high reliability is widely used in aerospace industry, But the traditionalphotoelectric encoder can not adapt to the harsh space environment. Therefore, in orderto improve accuracy and reliability of the satellite laser communication control systemto further strengthen the spatial adaptability and fault diagnosis research of photoelectricencoder is of great significance.At first, we analyzes the design requirements and the basic principle of work of thecoarse pointing feedback unit, and complete the design with the photoelectric coder inthis paper. Second, in the subdivision, we analyze the decoding error of encoder causedby the space high temperature, and solve the problem of poor linearity of the code value.Third, encoder decoder error caused by the axis deviation is analyzed, and the problemof code hopping caused by the changes of shaft is solved. fourth, we analysis thedecoding error caused by the quality of Moire signal, and put forward the correspondingcompensation measures, in order to improve the precision of encoder decoder.Finally, aiming at the characteristics that the analog circuit of photoelectric encoderoften wrong, we design a fault diagnosis scheme which is based on the support vectormachine theory and using the wavelet packet transform to extract fault feature we usethe fault diagnosis system on the analog circuit and decoding signal, which simplifiesthe debugging process of analog circuit, completes reconstruction of the decoding signalfault, and enhance the reliability of the feedback unit.