Browsing International Telemetering Conference Proceedings, Volume 31 (1995) by Subjects
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A SOFTWARE APPROACH TO MARS-II DIGITALLY RECORDED TELEMETRYThe MARS-II digital recorder is one of the new technologies that will eventually replace the labor intensive and hardware dependent methods associated with traditional analog-based telemetry ground systems. The Standardized MARS-II Analysis and Reduction Tool (SMART) is one of the first software systems developed to take advantage of this new digital recording capability. It processes pulse code modulated (PCM) encoded data and MIL-STD-1553B message traffic, outputting time-tagged PCM frames or 1553 messages to file. The goal of this software is to provide a portable application that utilizes state-ofhe-art, general purpose hardware for rapid telemetry data processing to meet the needs of operational users, telemetry engineers, and data analysts. To satisfy these goals, the software was developed using the C language with VMS and OSF operating systems as the initially targeted platforms. In addition, an X Window System/Motif graphical user interface supporting three tiers of user interaction (operator, telemetry engineer, and telemetry analyst) was layered onto the decommutator functions.
TELEMETRY AS AUTOMATAIn its simplest form an automaton can be considered a set of inputs, a process, and a set of outputs. Certainly telemetry can be thought of in this way as well. Automata theory is a cross between mathematics and computer science which considers how to precisely define the inputs, the outputs, and the process of translating the one into the other. The input to an automaton can be described using a formal grammar. Two standard bit stream encodings, PCM matrices and MIL-STD-1553, are described using grammars. An example of how a grammar can be used to decode a bit stream is given. Further, ambiguity and complexity of bit stream encodings are discussed in the context of grammars. It is thus illustrated how grammars can be used to cleanly define and decode telemetry bit streams.