Leveraging Gated Recurrent Units for Iterative Online Precise Attitude Control for Geodetic Missions

TL;DR

This paper introduces an iterative PID control enhancement using Gated Recurrent Units (GRU) to predict and compensate for external disturbances, significantly improving attitude control precision in geodetic satellite missions.

Contribution

The paper proposes a novel integration of GRU-based disturbance prediction with PID controllers for real-time attitude control in space missions.

Findings

Significant reduction in attitude error demonstrated in simulations.

GRU effectively predicts external disturbances from satellite data.

Enhanced control precision without replacing existing PID controllers.

Abstract

In this paper, we consider the problem of precise attitude control for geodetic missions, such as the GRACE Follow-on (GRACE-FO) mission. Traditional and well-established control methods, such as Proportional-Integral-Derivative (PID) controllers, have been the standard in attitude control for most space missions, including the GRACE-FO mission. Instead of significantly modifying (or replacing) the original PID controllers that are being used for these missions, we introduce an iterative modification to the PID controller that ensures improved attitude control precision (i.e., reduction in attitude error). The proposed modification leverages Gated Recurrent Units (GRU) to learn and predict external disturbance trends derived from incoming attitude measurements from the GRACE satellites. Our analysis has revealed a distinct trend in the external disturbance time-series data, suggesting the potential utility of GRU's to predict future disturbances acting on the system. The learned GRU model compensates for these disturbances within the standard PID control loop in real time via an additive correction term which is updated at regular time intervals. The simulation results verify the significant reduction in attitude error, verifying the efficacy of our proposed approach.