用於無人機載具之光通訊地面系統設計與整合測試

Abstract

中文摘要 本研究針對無人機光通訊地面站之追蹤需求，設計一套結合超寬頻定位、資料運算、可程式邏輯控制器及雙軸伺服雲台之自動追蹤系統。系統透過五個 UWB 固定站量測移動站與各固定站之距離資訊，以最小平方法解算目標三維座標，再轉換為方位角、仰角與伺服控制脈衝，由 PLC 驅動雙軸雲台完成目標指向。 為驗證系統可行性，本研究進行 UWB 定位精度、角度計算、追蹤更新率及雲台指向誤差實驗。UWB 靜態定位測試之平均三維定位誤差為 16.19 cm，RMSE 為 19.10 cm，具備約 20 cm 等級之粗定位能力。目標方向計算之方位角平均絕對誤差為 1.217°，仰角平均絕對誤差為 5.332°。平均追蹤更新頻率為 0.637 Hz，約每 1.5 秒完成一次位置更新與控制命令輸出。雲台指向實驗取得 84 筆雷射光點量測資料，平均徑向指向誤差為 5.124 cm，RMSE 為 7.164 cm，約 79.8% 的量測資料維持於 3 cm 以內。 實驗結果顯示，本系統已完成 UWB 測距、三維座標解算、角度換算、PLC 通訊及雙軸雲台控制之完整流程整合，具備無人機自由空間光通訊之粗追蹤能力。

Abstract This study develops an automatic tracking system for ground stations used in unmanned aerial vehicle (UAV) free-space optical communication applications. The proposed system integrates Ultra-Wideband (UWB) positioning, data processing, a Programmable Logic Controller (PLC), and a dual-axis servo gimbal. Distance information between a target and five UWB anchor nodes is obtained and processed using the least-squares method to estimate the three-dimensional coordinates of the target. The calculated coordinates are then converted into azimuth angles, elevation angles, and servo control pulses. Finally, the PLC drives the dual-axis gimbal to achieve automatic target pointing. To evaluate the feasibility of the proposed system, positioning accuracy, angle calculation accuracy, tracking update rate, and gimbal pointing performance are investigated. The results show that the system provides coarse positioning capability at approximately the 20 cm level and successfully performs target direction calculation and automatic tracking control. The gimbal pointing tests indicate that most measurement data remain within a small error range, demonstrating good tracking stability and repeatability. Overall, the developed system successfully integrates UWB ranging, three-dimensional coordinate estimation, angle conversion, control signal transmission, and dual-axis gimbal control, providing coarse tracking capability for UAV free-space optical communication ground stations.