Research On Spaceborne Multi-sensor Information Fusion Method

With the development of science and technology,artificial satellites play an extremely important role in the daily life of our defense research.According to the complexity,the satellites are divided into two types: multi-task complex satellites and single task small satellites.The composition of the multi-mission satellites is quite complicated and requires extremely high precision of measurement and control.In order to reduce the risk of losing control of a satellite due to failure of components and increase reliability,it is often performed on-board backup of various key measurement control components,so that the cost of developing and manufacturing such a satellite is high.The single task small satellite not only can perform a simple task,but also can complete complex tasks through the collaboration of multi-satellites.For complex satellites with extremely high precision of measurement and control,its measurement and control system is usually equipped with a variety of attitude sensors such as infrared horizon sensor,high-precision CCD star sensor high-precision gyro combination and so on.It is not only to meet the needs of the satellite in different space environment,such as the period before the separation from the rocket and the satellite into the shadow of the earth,but also the need of the system backup.Accurate measurement is an important part of achieving precise control.In order to make full use of the valuable resources on the astral,make the best use of it,and improve the precision of attitude measurement,the information fusion method multi attitude sensors in the spaceborne needs to be studied.Furthermore,taking into account the intense heat exchange in the satellite orbit environment,the installation of external attitude sensor tooling have expansion and contraction deformation,and the star sensor output contains the low frequency thermal deformation error(TDE);Therefore,it is necessary to study the method of analysis and compensation of TDE.In this paper,aiming at the problem of thermal error in the star sensor attitude measurement,the quaternion of the star sensor is Fourier transformed,combined with the output information of the gyro assembly installed in the satellite which is less affected by heat exchange,and through spectrum analysis and least square method,the frequency of TDE and the amplitudes of fundamental frequency and frequency multiplier are determined,then TDE is compensated.In order to further improve the attitude measurement precision,Firstly,the Kalman filter is applied to infrared horizon sensor,high-precision CCD star sensor high-precision gyro combination and other kinds of attitude sensors and obtain the high-confidence output;Then according to the inherent error of each sensor to improve the information distribution factor algorithm,Finally,multi-source information fusion is carried out to output the optimal attitude information.The simulation results show that the accuracy of attitude determination of the system that compensates for TDE and uses multi-sensor information fusion has been significantly improved,and the method is feasible.