Real-Time Attitude and Orbit Control System of a Small LEO Satellite with Parallel-Processing Approach in a Ground Station

Real-Time Attitude and Orbit Control System of a Small LEO Satellite with Parallel-Processing Approach in a Ground Station

A Real-time Attitude and Orbit Control System (AOCS) using a parallel processing approach will be implemented using a Satellite Ground Control Station (SGCS). With this approach, the satellite will collect platform (attitude reference) and payload measurements (at 1Hz) over several orbits and down-link to the SGCS (at 5 KHz) where the real-time filtering, fault detection, diagnosis and corrective (if needed) control is generated. The control commands are up-linked to the satellite before losing telemetry lock. A substantial reduction in on-board computation can provide a cheaper and a higher reliable AOCS. In the proposed scheme, an advanced real-time estimation and control algorithm in the SGCS for monitoring the critical parameters of the system will be described for a gravity gradient stabilized Low Earth Orbit (LEO) satellite. The parallel (or distributed) processing technique effectively reduces the computation time and increases the subsystem performance dramatically where computation time becomes a critical factor due to the low earth orbit operation. The proposed scheme is based on (1) a Kalman Filter (KF) to perform the real-time estimation of the critical parameters, (2) a parallel processing technique to reduce the computation time, and (3) their implementation with an advanced control algorithm to reconfigure the complete AOCS from the SGCS (if necessary).