关键词: 激光跟踪, 星间基线, 快反镜, 光线追迹, 误差传递

Abstract: To address the precise determination requirements of inter-satellite baselines for high-accuracy elevation measurement in spaceborne distributed interferometric synthetic aperture radar (InSAR), this study proposes a high-precision inter-satellite relative position measurement method based on active laser tracking. A high-precision inter-satellite relative positioning system is constructed by integrating large-range precise ranging based on femtosecond optical frequency combs with precision pointing and angle measurement relying on fast steering mirrors (FSM) and position-sensitive detectors (PSD), enabling high-precision ranging as well as tracking and angle measurement simultaneously. An accurate and complete spatial relative position measurement model is established via the ray-tracing vector analysis method. Combined with the law of error propagation, Monte-Carlo numerical simulations are carried out to investigate the variation patterns of relative positioning precision with the ranging error of femtosecond optical frequency combs and the tracking pointing angular errors of FSM and PSD, hereby completing the tracking and positioning error analysis. Simulation results demonstrate that within an inter-satellite distance of 300 m, the system achieves a tracking field of ±1.5°, with the combined three-axis position measurement precision better than 1 mm. This method enables high-precision determination of long-distance distributed satellite base-lines, meeting the requirements of future spaceborne distributed InSAR and other precision formation tasks.

Key words: laser tracking, inter-satellite baseline, fast-steering mirror, ray-tracing, error propagation