High-precision dynamic pointing method for improving the acquisition performance of laser communication between high-altitude platform stations

Abstract

Fast and stable acquisition is the prerequisite for establishing a space laser communication links. In this paper, the acquisition technology of establishing a space laser communication link between high-altitude platform stations (HAPS) is studied, a dynamic pointing and scanning model is established, and the acquisition performance of the laser communication system under line of sight (LOS) disturbance is analyzed based on this model. To improve the acquisition performance, we propose a high-precision composite pointing method to reduce the pointing error of the line of sight. A composite pointing controller with a fast steering mirror (FSM) is designed to reduce pointing errors, and the aiming accuracy of line of sight is improved by predicting the target with improved unscented Kalman filter (IUKF). A dynamic laser communication experiment based on HAPS is built to verify the method. The results show that the proposed method reduces the initial pointing error by 45%, and the stability of the line of sight is increased by a factor of 5. By conducting several acquisition tests, the average acquisition time is 1.57 s with 100% acquisition probability. The acquisition performance is significantly improved compared with that before the improvement, in which the acquisition probability is increased by 8% and the acquisition time is reduced by 44.3%, which verifies the effectiveness of the proposed method and lays the foundation for the establishment of a fast communication link for laser communication between HAPS.