The Navigation Method Of Formation Flying Satellites Based On Baseline Information / Pulsars

Formation flying satellites have become one of new research fields in recent years, which introduce the concept of computer network topology, combinate several satellites in accordance with a certain shape, make use of inter-satellite links to communicate and work together, complete the task that traditional satellites can‘t finish. Because of its advantages of low-cost, high-perforamnce, good-flexibility and fault-tolerant system, the concept of formation flying satellites has received widespread attention at home and abroad aerospace industry since first put forward. Its potential in scientific experiments, deep space exploration and near-earth probing attracts more attention of scientists from different countries. The states of foramtion satellites must be determinated in order to make them work together, so the navigation of formation satellites become one of the key problems that must be solved. Most of the relative navigation technologies of formation satellites are based on GPS or technology similar to GPS. GPS has the disvantage of easily to be interferenced, so it can‘t achieve the task of formation satellite navigation in high orbit condition or deep space exploration.Pulsars can emit pulses towards the universe in a precise period, so it‘s called the lighthouse of the natural. X-ray pulsars have received high attention of scientists for its potential in navigation since it was discovered half a century ago. The method of X-ray pulsar-based navigation can be applied to deep space exploration and earth-orbiting spacecraft navigation, and it has good performance in reliability and autonomy. But high-precision navigation cannot be achieved if the input of navigation system is only the signal of pulsars, neither can meet the requierments of formation flying. A new method of formation satellites autonomous navigation is proposed in this paper, which makes use of pulsars timing observaitons and the measurement of inter-satellite baseline to determine the states of formation satellites. In this paper, the mathematical models of two satellites formation and three satellites formation are proposed, and the corresponding UKFs are also designed to estimate the position and velocity of the satellites.The new method this paper proposed is tested on Matlab in the case of two satellites formation and three satellites formation. The results show that the new method is corrective and feasible, and the navigation accuracy is improved obviously. The application of formation flying pulsars has good prospects, and the method this paperproposed has important significance for the application of satellites formation.