Research On Related Technology Of Fault Detection And Diagnosis For Satellite Networks

Inter satellites links (ISLs) increase the complexity of satellite networks while upgrading the connectivity and autonomy. Fault detection and diagnosis are crucial to support the reliability and fault-tolerance of these networks. However further effort should be put on fault diagnosis for satellite networks.In this paper, system level diagnosis (SLD) is introduced into satellite networks with ISLs and researched mainly on the problems of system modeling, test model, algorithm's design and evaluation. SLD, inosculating detection and diagnosis as a whole, can diagnose networks from the higher level. It not only has simple theory, but also can avoid involving in too much professional knowledge about satellites. Moreover, the numerical solution of analysis of electromagnetic, a basic work of detecting faults in satellites, is discussed to help to diagnose faults from lower level based on the results of system level diagnosis, because the core of satellites are composed of electronic and electric devices. The main work in this paper includes:(1) Modeling methods for satellites and satellite networks are presented. According to the communication theory of satellites, "port" is abstract as the diagnosed node. And then "two-level node graph" is presented to model the topology and test structure of a satellite network. Furthermore, the generalized test invalidation model is extended based on the given fault types.(2) A system-level fault detection and diagnosis method for satellite networks is proposed to identify the states of ports. Especially, a diagnosis algorithm is presented based on the rules deduced from our extended test invalidation model and its correctness is proved. Moreover the communication overhead and diagnosis delay isanalyzed theoretically.(3) A simulation structure is proposed to evaluate our system level fault detection and diagnosis algorithm for satellite networks. The communication overhead and diagnosis completeness are evaluated deeply by simulations with different conditions. Results illustrate that our method adapts to arbitrary topology networks and has good robustness.(4) A numerical algorithm of Wavelet Interpolation Galerkin method(WIGM) for the boundary problems of static electromagnetic fields with irregular regions is presented. Its error in Sobolev space is evaluated.