DEVELOPMENT OF AN OBJECT-ORIENTED SOFTWARE APPLICATION TO PROVIDE A TRANSPARENT INTERFACE BETWEEN SPACE NETWORK OBJECTS AND A TELEMETRY SYSTEM FOR TRAINING

Abstract

The Space Station Verification and Training Facility is using an object-oriented design methodology for software design, a rate monotonic scheduling and message passing system to support the highly distributed environment, and the Ada language to implement most of the software. One of the subsystems within the Space Station and Training Facility is the Space Network Simulator. Space Network simulators are used to provide training of ground controllers and flight crews, providing a model of real-world formats and protocols. This gives the controller the appearance of a real-world network, providing valuable training. To develop a simulation of the space network within this distributed environment, software objects are under development to dynamically simulate the existence of the space vehicle(s) and their communication components. Communication components include the on-board antennas, transponders, communication systems, and corresponding communication ground control facilities. Telemetry systems are used in the simulation to provide the control of actual data manipulation, as a function of the state of the simulated Space Network. The telemetry system automatically formats appropriate telemetry characteristics through mode and control commands. A software model is under development to provide a transparent interface between the software objects and the telemetry system, allowing the objects to execute without knowledge of the particular telemetry system in use. A transparent interface between the software and hardware, within this object-oriented methodology, reduces the propagation of change to software models as the interface requirements change.