Research On The Path Planning And Control Method Of Small Satellite Formation

In recent years,sparse aperture sensing and stellar interferometry are becoming more and more mature,which is one of the research hotspots of synthetic aperture radar(SAR)satellite formation.Through the formation of SAR satellite,the recognition of ground moving target,the enhancement of image resolution and the acquisition of elevation digital model can be realized.Miniaturization,high resolution and wide swath are the development direction of SAR satellite formation in the future.The system cost of SAR satellite can be minimized by proper array,and its distributed formation structure is innovative in space system design.Therefore,the main research contents of this paper are as follows:Considering the perturbations and the changes of the orbit elements of the main star with time,a more accurate nonlinear dynamic model is established,and the periodic relative motion and energy matching motion of the linear C-W equation and the nonlinear model are analyzed.Based on the sequence convex optimization method to solve the problem of multi satellite formation reconstruction trajectory planning,the collision avoidance constraints involved in the reconstruction process are convex by using the center method,the serial decentralization method and the parallel decentralization method,and the calculation time and fuel consumption of small formation and large formation are compared.The simulation results show that the parallel decentralized method has the shortest solution time and the least fuel consumption.In order to alleviate the communication burden between satellites and reduce the dimension of dual variables,a distributed satellite formation system is designed based on dual decomposition method.Aiming at the problem of long solution time and large dimension of dual variables,the formation is designed as a distributed system,which reduces the calculation time and dimension of dual variables and reduces the pressure of satellite communication.In order to reduce the influence of external interference on the precise formation keeping,a sliding mode controller based on reaching law and a fast terminal sliding mode controller are designed,and the chattering of the sliding mode controller based on reaching law is suppressed by using the continuous function of saturation function and relay characteristics.The simulation results show that the effect of terminal sliding mode control and saturation function is more obvious.