Modeling And Implementation Of The Basic Service Layer Of Spacecraft Onboard Software Middleware

The SOIS(Spacecraft Onboard Interface Services)was established by the CCSDS(Consultative Committee for Space Data Systems).The SOIS provides a layered set of communications services for flight avionics.This set of services covers the majority of onboard communications requirements.The SOIS services consist of Application Layer services,Application Support Layer services,Transfer Layer services and Subnetwork Layer services.The SOIS Area does not directly specify protocols.It defines the services to be supported by the underlying protocols.An implementer may choose to apply all services or only a selection relevant to a particular implementation approach.It is by no means mandatory to take benefit from the SOIS service specifications.In this case,spacecraft interface development is based on a particular project.The different developers of spacecraft interface may adopt different solution.At the international level there have so far been very few significant attempts at standardizing spacecraft onboard interfaces,and consequently incompatible interfacing solutions have evolved.In the actual project,the use of different implementations of SOIS may increase the difficulty of realizing software reuse,and manual changes are needed.Therefore,the standardization of SOIS and research on SOIS compliance are significant to accelerate the development of spacecraft software,reduce the cost and improve software maintenance.This paper studies the evolution and the compliance of SOIS,and reference architecture of SOIS.Then the related services of Application Support Layer,Subnetwork Layer are elaborated.Then we model and implement the Application Support Layer services and Subnetwork Layer services based on AADL and the software bus of spacecraft onboard.Finally,the services are tested and we take an example to introduce how to apply SOIS services in project.