Preliminary PANSAT ground station software design and use of an expert system to analyze telemetry

Abstract

The Petite Amateur Navy Satellite (PANSAT) is a communications satellite designed to be used by civilian amateur radio operators. A master ground station is being built at the Naval Postgraduate School. This computer system performs satellite commands, displays telemetry, trouble-shoots problems, and passes messages. The system also controls an open loop tracking antenna. This paper concentrates on the telemetry display, decoding, and interpretation through Artificial Intelligence (A.I.). The telemetry is displayed in an easily interpretable format, so that any user can understand the current health of the satellite and be cued as to any problems and possible solutions. Only the master ground station has the ability to receive all telemetry and send commands to the spacecraft; civilian ham users do not have access to this information. The telemetry data is decommutated and analyzed before it is displayed to the user, so that the raw data will not have to be interpreted by ground users. The analysis will use CLIPS imbedded in the code, and derive its inputs from telemetry decommutation. The program is an expert system using a forward chaining set of rules based on the expected operation and parameters of the satellite. By building the rules during the construction and design of the satellite, the telemetry can be well understood and interpreted after the satellite is launched and the designers may no longer be available to provide input to the problem