• AN OBJECT-ORIENTED COMMAND AND TELEMETRY "BLACK BOX" SIMULATION USING ADA

      Policella, Joseph; White, Joey; Shillington, Keith; CAE-Link Corporation; Fastrak Training Inc. (International Foundation for Telemetering, 1993-10)
      To model the "black boxes" in a command and telemetry simulation, it is important to preserve the abstraction of a one-to-one match between the real-world interfaces and the simulated interfaces. Everywhere a physical interface exists on the box, there needs to be a simulated interface. Preserving this abstraction allows the model to evolve more naturally with real-world design changes. In most command and telemetry systems, many different types of commands and telemetry can be sent over a single interface. This creates a problem in preserving the interface abstraction if the Ada language is used for implementation. Due to the fact that Ada is a "strongly typed" language, a different or overloaded operation needs to exist for each type of command or telemetry. However, by using a "discriminated variant record" to represent the commands and telemetry streams, a single operation can be used in the Ada specification. This not only preserves the abstraction but makes the software more maintainable by allowing the data list to change during the design of the "black box" without changing the Ada specification. As a result, "loose coupling" is achieved, a common set of commands and telemetry formats can be "inherited" to promote reuse, and overall system development and maintenance costs are reduced.
    • A SYSTEMATIC METHOD FOR SYNTHESIS OF OBJECT ORIENTED SOFTWARE DESIGNS FOR TELEMETRY SIMULATION

      White, Joey; Policella, Joseph; CAE-Link Corporation (International Foundation for Telemetering, 1993-10)
      A tremendous amount of work has been done recently in the area of Object Oriented Design (OOD) methodology. Most often, texts and papers explaining these methodologies are centered around the explanation of some arcane graphical notation. One is led to believe that the key to understanding Object Orientedness in general will be found by understanding and applying this notation. An understanding of the essence of OOD is difficult to acquire in this manner due to the disproportionate amount of energy required to memorize the graphic symbology. The prospective designer is often left with an understanding of the symbols, but with no understanding of how to apply them to a real world large scale problem. This paper provides an explanation of the Object Oriented paradigm with an example application to telemetry measurements. Next this paper provides an explanation of the most popular graphic notation for Object Oriented Design, the Booch Notation. Finally, this paper shows an alternative graphic notation that can be effectively used in Object Oriented Design during the initial stages of design to help eliminate the learning curve associated with the more popular Object Oriented notations.