Health Monitoring of a Satellite System

A health monitoring system based on analytical redundancy is developed for satellites on elliptical orbits. Analytical redundancy, which reduces the need for hardware redundancy, uses the modeled dynamic relationship between system inputs and measured system outputs to form a residual process that is used for detecting and identifying faults. First, the dynamics of the satellite including orbital mechanics and attitude dynamics is modeled as a periodic system. Then, periodic fault detection filters are designed to detect and identify the satellite’s actuator and sensor faults. In addition, parity equations are constructed using the algebraic redundant relationship among actuators and sensors. Furthermore, a residual processor is designed to generate the probability of each fault by using a sequential probability test. Finally, the health monitoring system, consisting of periodic fault detection filters, parity equations, and residual processor, is evaluated in the simulation in the presence of disturbances and uncertainty.