Control algorithms for improved high pointing accuracy and rate stability in agile imaging spacecrafts

The current era has witnessed a huge demand across the globe for stringent pointing accuracy for Earth observation imaging payloads. This paper brings to light a novel improved controller for high precision pointing accuracy and jitter reduction. The pointing accuracy is judged in terms of the reference tracking capability of the imaging satellites. This improved precision pointing technique aims at reducing the jitter and disturbances thereby enhancing the on-board imaging quality of remote sensing missions. Simulation results are in conformation with the fact that the proposed control algorithm which is a modification over the standard P-D controller, attempts to achieve high pointing accuracy as compared to the existing limits of accuracy. The principle is applied to Zero-momentum Reaction wheel system. The improved Dual Integral Position and Rate mode control algorithms, together with fine pointing stage, for onboard single axis stabilized operation are demonstrated by simulations undertaken in SIMULINK/MATLAB.