Design And Application Study Of Intelligent Flight Software Architecture On Spacecraft

In space engineering area,Space Data System and flight software development mainly face problems such as diversity of onboard interfaces and application protocols among different projects.Users' requirements are always unknow,often changed and more complex.More and more missions need spacecrafts to be organized as cluster,array,constellation to flight,need networks among spacecrafts and integrated satellites with terrestrial systems.The requirements complexity conflicts to the target of "faster,better,cheeper".The resolution is application of reused technology,intelligent technology and appropriated development modes.It needs a spacecraft data management software architecture to support the methods above.Based on Consultative Committee for Space Data Systems(CCSDS)Space Onboard Interface Services(SOIS)architecture,this dissertation designed and studied an intelligent software architechture to solve the problems of autonomic control,unified protocols,reusage features and sustainable development process.CCSDS SOIS architecture and some of its instances(SAVOIR by ESA,cFE/cFS by NASA,and follow up studies and practices in China),and ECSS PUS,are analysed and compared,and obtained two enlightments.One is that the key feature of reuse is modeling,and the other is that the data design method with EDS technology will be a trend.SOIS architecture includes two supporting technologies,i.e.Plug and Play(PnP)and data management.At PnP aspect,IEEE1451 serial protocols standards,AFRL SPA architecture and SOIS SEDS are discussed,and thoughts of PnP is concluded.At data management aspect,some typical aerospace projects with application of intelligent technology are surve ied.According to survey conclusions and some references,from the deployment viewpoint,an intelligent capability level model on spacecrafts is given,and used as start point and framework of this dissertation.Firstly,an onboard intelligent software architecture named "People Shape Architecture(PSA)" is suggested,because it composed with two supporting technologies(PnP and autonomic control platform)to construct intelligent body above them,just like chinese character "?"(a people).Basic Function Service Model(BFSM)is also given.MIB and EDS concepts used for descript relationship of data and protocol stack among BFSMs.Component concept can be described abstractly as application,service and device.Every component has its own self-describe EDS.As core data structures in a system,three levels(service,device,system)MIBs are used for storing and exchanging EDS,to represent corresponding and organization relationship.Secondly,at PnP aspect,based on traditional 1553 B data bus protocol(mainly ECSS-E-ST-50-13C),a new protocol with Plug and Play(PnP)features is designed by adding Remote Terminal Electronic Data Sheet(RT EDS)and procedure of transferring EDS.According to this protocol,the PnP resolution of 1553 B Bus Controller(BC)is designed,including constructing bus list algorithm,management data structure,and dynamic operation and control bus list method.The constructing bus list algorithm uses RT EDS to analyse,calculate and transform an old bus list to a new one,to satisfy RTs' communication requirements.Management data structures are used for analysis and store bus list information during initialization phase,to increase efficiency of operation control and data exchanging.The way of d ynamic operation and control bus list adopts main bus list with plug in messages method.The timeliness and use cases of the resolution are evaluated.The results show that its period of bus cycle and time of RT plug into the system can be accepted.The resolution can remain stable of communication process,and provide flexibility for PnP needs.This resolution solved the problems of RTs' auto-recognization and auto-configuration,enhanced adaptability of a system with 1553 B data bus to heterogeneous devices and protocols.In CCSDS SOIS architecture,1553 B data bus is one of subnetworks on the bottom layer.With PnP features,it can be extended to support constructing PnP system services and functions of higher layer.Thirdly,at intelligent autonomic control aspect,a 5-stage model is constructed,including telecommand data receive,task executive,self-learning,system self-manangement,task self-manangement and thinking capabilities.The target of this model is to support teleoperation,common use and reusage.According to CCSDS Space Packet Protocol and ESA PUS,common command formats and inner management data structures are designed.It is an unified roadmap of thoughts to construct levels of the intelligent auntonomic platform bottom-up.From intelligent capability viewpoint,this model supports three degrees of intelligence capability(automatic,autonomous and autonomic),three levels of capability behavior(bottom-reaction,middle-programe,top-thinking),and gradually constructing self-study capability,system self-management capability,mission self-management capability and high level thinking capability in an intelligent system.Finally,in order to construct the intelligent software architecture above and use intelligent technology,a standard system of spacecraft data system is proposed.In order to satisfied current engineering constraints and reuse requirements,several improvement suggestions of aerospace software engineering process are discussed,such as Function Oriented Software Engineering Process(FO-SEP)3V-model,appropriated organization style and reusable environment.The 3V-model can be used for three kinds of development process,i.e.a new software project without reusage,a function component construction process and a completely using reusable components process to construct a software product.Conceptions above can make software development independent of hardware works,response users' requirements rapidly,and even lead users' expectation.This subject bridges traditional aerospace software development and enhancement of intelligent capability,which will contribute to the foundation and roadmap of using space data system intelligent technology on spacecrafts.