Micro-vibration Modeling and Suppression Technology and Prospects for High Resolution Remote Sensing Satellite

Abstract

With the development of remote sensing satellite technologies, and the pressing demand for high resolution, high agility and low costs for remote sensing satellites, integrated design of platform and payload has been a growing tendency, which could remarkably reduce cost, volume and mass. However, compared to traditional designs, remote sensors in the integrated design are much closer to vibration sources, implying that the micro-vibration environment of remote sensors become even worse. Although the micro-vibration is so small that its influence to structure is negligible, it could result in considerable reduction of image quality of high resolution remote sensors. Micro-vibration has become a critical factor for high resolution image quality especially in the integrated satellites. In this paper, the micro-vibration modeling technology including disturbance source modeling, coupling of structure and control system and comprehensive evaluation technology will be discussed. In order to verify the correctness of the micro-vibration integrated modeling and comprehensive evaluation technology and evaluate the effectiveness of the micro-vibration control system, ground test and in orbit measurement have been done, but the differences between the ground and the earth need further study. For the effects of micro-vibration on image quality, given the distribution of micro-vibration amplitude and frequency, the performance indicators of payload such as MTF and image motion can be given, but for the inverse problem, that is, given the desired performance of payload, the conditions that the vibration distribution should meet cannot be clearly given. This is very important for the selection of micro-vibration suppression methods and related parameters. To reduce the effects of micro-vibration on image quality, many vibration isolation methods have been adopted in high resolution satellites. According to the different vibration isolation modes, vibration isolation can be divided into four types: passive, active, active-passive integrated and semi-active. Some advanced nonlinear vibration isolation technologies, such as nonlinear stiffness and nonlinear damping technology, have achieved good results in low-frequency and broadband vibration isolation, and have high reliability, which may be a trend to solve high-precision spacecraft vibration isolation in the future. Finally, some suggestions on reducing the influence of micro-vibration on the imaging quality are proposed. Firstly, it is necessary to control the generation of disturbance vibration from the source, reducing the manufacturing and assembly errors of disturbance vibration sources such as CMG, momentum wheel and refrigerator. Secondly, we should keep on developing system modeling and measurement technology, analyzing the transmission characteristics of micro-vibration to find out the key links of micro-vibration generation and transmission. Thirdly, micro-vibration suppression technology should be vigorously studied to make the parameters of high-frequency vibration and low-frequency vibration meet the requirements of payload and create a “quiet” mechanical environment for payload. Fourthly, we should improve the “tolerance” ability of the payload itself, and study the corresponding vibration compensation measures and image processing methods.