Software Design On The Payload Task Simulation System Based On HLA

Being the core part of payload ground support system, spacecraft operation center is responsible for making plans of the payloads on the shuttle. It builds up the commands list and sends them to the shuttle, monitors the status of the payloads by house keeping parameters, receives science data and provides the data product to the scientists after the process routine.Lots of software and operators are involved in the spacecraft operation center. To improve the quality of the software, build up the training environment for the operators, strengthen the support to plan-making and failure-detecting procedure, a payload task simulation system is needed.Based on the study of the application of payload task simulation system, this paper extends the function of payload task simulation system to the plan-making and failure-detecting area. This paper also gives a deep study on the problems of distributed system, which payload task simulation system has to face, and finds the solutions based on HLA technique. To solve the problem that HLA is not good at real-time volume data transmitting, a multicast-HLA integrated solution is described in this paper. Because most changes of payload task simulation system come from payloads, the software system architecture is built up in this paper, in which all the payloads locate in non-critical points. This architecture makes the system more flexible and configurable.The biggest problem of building a system based on HLA is about time management service. This paper gives a deep study in time management and introduces a management role in the data simulation system to implement a step-forward time management strategy, which makes the speed of the simulation system adjustable.This paper also gives a look into each federate in the federation, and shows reader the flow chart of the time forward loop for each module. This is really helpful to implement the federate.The studies in this paper give a good supporting environment for further research on the payload task simulation system.