Research on High-Precision Composite Axis PAT System for Inter-Satellite Dynamic Laser Communication

In response to the requirements for stable tracking in inter-satellite dynamic laser communication links, and in order to ensure the rapid construction of space-based broadband information networks, we conducted research on a high-precision composite axis targeting, acquisition and tracking system for inter-satellite dynamic laser communication. Based on the composite axis targeting acquisition and tracking (PAT) system composed of large range coarse tracking unit and large bandwidth fine tracking unit, the composite axis servo control model is established and optimized. Compared with the traditional 2D servo control model, this model has the characteristics of large range, large bandwidth, no independent beacon and high precision, which can effectively support the accurate chain construction of laser communication. Meanwhile, through the verification test of the inter-satellite laser communication terminal set up in the indoor equivalent verification environment, in the external high-frequency disturbed environment of 1Hz@100 μrad, 100Hz@4 μrad, 200Hz@0.6μrad, the chain is built within 10s, and the tracking accuracy RMS value is 2.54μrad (3σ). This experiment verifies the effectiveness of the high-precision Pointing, Acquisition, and Tracking (PAT) system, holding significant importance for the development of high-speed coherent inter-satellite laser communication.