Reserch On The Key Techniques Of Micro-satellite Intelligent Keeping Opatator

Not only in the development of single star but alse in the development of micro-satellite formation flying and constellation systems the demands on intelligence and autonomous in micro-satellite keeping operator are increasing. This paper just study on some key techniques of'TX-1'micro-satellite keeping operator which is being researched in Nanjing University of Aeronautics and Astronartics.The mission of'TX-1'micro-satellite is divided into nine tasks. The heuristic scheduling method of'Merger-Threshold'is applicated to distribute these nine tasks. According to the shortcomings of the Merger-Threshold scheduling method a scheduling method based on genetic algorithm is studied and applicated to optimize the scheduling. In order to realize dynamic tasks scheduling, an intelligent autonomous scheduling method based on fuzzy neural network is presented in this paper. In this method the order requirement of some tasks and the different working conditions of some tasks are both consided. This method firstly classifies tasks according to the working order of tasks, then automatically decides the present reqirement of satellite by the present conditions and finally realizes dynamic tasks scheduling.There are many temperature measurement points in satellite, so the hardware redundant design method will increase much power consumption, volume and weight of satellite. Therefore, a redundant design method based on data fusion is presented in this paper. Temperature sensors are devided into several groups according to the positons. The sensor in one group offers reference to each other. Based on the references, the credibility of each sensor can be calculated. When the credibility of one sesor is too low, the measurement result of this sensor is ignored and the back up senson is opened. By this way, the reliability of temperature measurement is improved.In normal operation of the satellite, in order to induce communication data and simplify monitoring task, several sensors are needed to give the estimate value of the temperature area. In this paper a data fusion method based on arithmetic average and batch estimate and a data fusion method based on Bayesian Estimation are studied and applicated to improve the accuracy of temperature measurement. Especially when some fault in one sensor, the estimate value still can reach high accuracy.In the basic task stage of'TX-1'micro-satellite ordinary remote sensing images will be achieved and in the exploratory task stage reconnaissance remote sensing images will be achieved. According to the ordinary remote sensing images, an improved EZW algorithm is studied. First, the image data are converted into lower frequency subimage and high frequency subimages by wavelet transform. Most of energy of images is in the low frequency subimag, so predicting coding method which almost loses no energy is used to compress low frequency subimage. And an improved EZW coding method is used to compress high frequercy subimages.According to the reconnaissance remote sensing images the most important element is to protect reconnaissance subimage. So an image compression method based on protecting reconnaissance subimage is presented. In this method, different methods are used to compress reconnaissance subimage and background subimage.Presently, most fault diagnosis system is carried out according to one subsystem of satellite. In this paper fault diagnosis method according to the whole satellite is presented. In order to decrease the amount of calculation the process of diagnosis is devided into two steps. In the first step fuzzy clustering method is used to estimate which subsystem works abnormally and in the second step the specific component or part with fault can be confirmed.