The Research Of Wavelet Transformation Domain Forecasting Compensative Method For The Angular Vibration In Satellite Optical Communication

This paper expanded the study for the problem of satellite platform vibration compensation. Summarized the sources and characteristics of satellite platform vibration, and discussed single-point feedback compensation method in detail based on existing literature. On this basis, a new compensation method, forecasting compensation method based on wavelet transform, was proposed by this means of introduction of wavelet theory in the field of mathematics. And the feasibility of this compensation plan was analyzed, specific work was studied as follows:Firstly, it described the development of satellite optical communications background, a detailed discussion of the sources and characteristics of satellite platform vibration. And in accordance with non-stationary vibration characteristics, prediction compensation method based on wavelet transform was put forward with introducing the principle and calculation in detail.Secondly, compensation ability of prediction compensation method based on wavelet transform was simulated and studied in the computer. From the satellite platform vibration characteristics, the paper design single sinusoidal and superimposed multi-sinusoidal two vibration modes. In each mode, forecasting compensation method based on wavelet transform and single-point feedback compensation method were used for vibration compensation. In single sinusoidal mode, by comparing the compensating factor of two different methods, an improved scheme was presented based on wavelet transform. The compensating ability of the improved method was much better than the previous method, especially for the high frequency vibration. The theoretical simulation shows that the improved method has a good ability of compensation for the 80Hz vibration, and its performance is better than a single point feedback method.Finally, author established a simulation system of satellite platform vibration compensation and produced a detailed experimental program. Similarly single sinusoidal vibration and superimposed multi-sinusoidal vibration were compensated with their effect being compared. The results showed that:under this experiment system parameters, the single-point feedback method is effective when the frequency of vibration is lower 30Hz if effective compensation threshold is set with 50%; However, the method based on wavelet transform is still effective even when the frequency is 80Hz. For superimposed multi-sinusoidal vibration, the single-point feedback method can compensate vibration of 21-30Hz frequency effectively, when frequency band is higher 21-30Hz, The compensation factor decreased to less than 50%; The method based on wavelet transform can effectively compensate the vibration of 51-60Hz. And the residual vibration after compensation with the method based on wavelet transform is more concentrated, most located in the vicinity of 0 μrad.By theory of the simulation and the experiment, it is proved that the prediction compensation method based on wavelet transform is feasible, its ability of compensation is higher than the single-point feedback method. The method provides a more effective suppression scheme for Satellite platform vibration.