Abstract: To improve the speed and precision of the diagnostic results based on satellite telemetry data, an integrated monitoring and diagnosis system using Multi-Agent including the diagnosis agent based on multisignal model, fuzzy diagnosis agent and expert system diagnosis agent is proposed. For the diagnosis agent based on multisignal model, the fuzzy range is introduced into monitoring system, and the confidence factor is presented to modify Deb’s real-time diagnosis algorithm in order to overcome the possible conflict of diagnostic results because of false alarm. Mamdani algorithm is used in fuzzy diagnosis agent that can give the failure probability for suspected components. Productive expert system based on rules is used in the expert diagnosis agent, and uncertain reasoning technology with weight is used to deal with uncertain information. The cooperation mode between agents is investigated, and the final diagnostic results are obtained by D-S evidence theory. The program is validated using some simulated telemetry data for a satellite and the results show that the integrated diagnosis system, which utilizes most of the advantages of three diagnosis methods, is accurate and fast to locate the failure components (the diagnostic time is generally less than 0.3 second for PIII800/256M computer) and is suitable to real-time online diagnosis for satellite based on satellite telemetry data.

Key words: satellite telemetry data, fault diagnosis, Multi-Agent, multisignal model, evidence theory