Based On GPS Relative Measurement Of Satellite Formation Flying Collision Avoidance Study

Formation flight technology is the core technology of the 21st century space systems. Defined by the distributed satellites consisted of many small satellites flying in formation to perform space mission together is equivalent to the capability of a large virtual satellite. Comparing with the traditional satellites, satellites in formation flying has the dominate advantages in many aspects. In this paper, the main work includes the following four aspects.Firstly, from the point of relative motion, several dynamical models have been established, including nonlinear equations, linear equations (such as Lawden equation, T-H equation and C-W equation), kinematic equations depicted with orbit element differences. And the periodic conditions of these equations are obtained.Secondly, this article describes a dual-frequency GPS navigation system structure and its unique measurement equation, and then gives its navigation filtering algorithm processes, which are the bases for the later satellite formation flying collision avoidance study.Thirdly, Based on T-H equation, the collision monitoring and collision avoidance maneuver strategies in an elliptical orbit for formation flying satellites were studied in this paper. By propagating the relative state covariance matrix forward and integrating the collision probability density in the risk region, the collision probability of the formation flying satellites was calculated. In the condition that the collision probability was exceeded the safety threshold, a miss distance was created at the monitored collision point across the collision probability gradient by applying an impulsive with minimum so that the collision point will be on the safety contour line. The simulation results showed that the collision monitoring method was available and the maneuver strategy was efficient.Finally, under the condition that the inter-satellite measurement equipment is broke down or even unavailable, in order to ensure the safe operation of the satellites, a passive anti-collision configuration is designed in this paper based on the analysis of the J2 perturbation configuration on the formation. And the use of mathematical programming methods to minimize time and fuel consumption for performance indicators and as a dynamic model of restraint conditions and criteria for anti-collision avoidance, evasion tactics and control research.