The Research And Prototype Implementation Of A General Satellite Realtime Operating System-SATOS

In general, satellites have a long lifetime in outer space and work in a very hash environment. The requirements of real-time Operation System(RTOS) for On-board applications on satellites is different from that for general real-time embedded software. This paper makes a primary summary of the software requirements of the general satellite RTOS and decides to develop our own general satellite RTOS compliant with that.The on-board software belong to safety-critical field and have the requirements of RTOS with safety-critical characteristic in space applications. This paper analyses the features deeply of the primary RTOSes used in safety-critical field and concludes the general advanced trends of the RTOS techniques. And this paper presents the qualification requirements which RTOSs in safety-critical field should meet colligating the current domestic research status of space applications.The software developing mode of open source has entered the space domain. The overseas space research institutes considers that it is a principal improvement way of developing and using open-source RTOS in the future. We chose a high quality RTOS - ORK which implemented and maintained by European Space Agency(ESA) from lots of open-source RTOSes. And based on the deep analysis & research of ORK, a better technical approach of developing our own general satellite RTOS was put forward in this paper.Ravenscar Profile was a restriction profile of Ada95 task scheme which defined at the 8th, 9th and 10th International Workshops on Real-Time Ada Issues. The procedure of schedulability analysis and program validation & verification for realtime system will benefit from the using of Ravenscar Profile in applications. So there is a great practical significance in converting Ravenscar Profile based on Ada95 language into the concurrent restrictions which not limited specific program language and the paper solves this problem primarily.SATOS, an RTOS prototype designed in this dissertation based on ORK's implementing technique, has passed the unit test and validation test performed by the software engineering department in 710 research institute, which was all rewritten in code level and had a much better functionality and performance.