Pointing-error correction of optical communication terminals on motion platforms using a parameter model and kernel weight function estimation.

Optical communication terminals (OCTs) with high pointing accuracy on motion platforms are highly important for establishing a global communication network. The pointing accuracy of such OCTs is seriously affected by linear and nonlinear errors generated by various sources. A method based on a parameter model and kernel weight function estimation (KWFE) is proposed to correct the pointing errors of an OCT on a motion platform. Initially, a parameter model, which has a physical meaning, is established to reduce the linear pointing errors. Then, the nonlinear pointing errors are corrected using the proposed KWFE method. Tracking star experiments are conducted to verify the efficiency of the proposed method. The parameter model reduces the initial pointing error associated with the stars used for calibration from 1311.5 µrad to 87.0 µrad. After applying parameter model correction, the KWFE method is applied to further reduce the modified pointing error associated with the stars used for calibration from 87.0 µrad to 70.5 µrad. Additionally, based on the parameter model, the KWFE method reduces the actual open-loop pointing error associated with the target stars from 93.7 µrad to 73.3 µrad. The sequential correction using the parameter model and KWFE can gradually and effectively improve the pointing accuracy of an OCT on a motion platform.