先進水文雷達系統整合及表面流速量測

本論文整合一24GHz都卜勒連續波雷達(Continuous Wave Radar)進行明渠流速觀測與量測應用分析研究。此雷達波流速儀為利用都卜勒效應，以非接觸式的方式測量水體表面流速的一種儀器。其運作原理是以連續波雷達對移動目標物體發射固定頻率之微波信號，因目標物體與雷達具有迫近或遠離的相對速度，雷達透過一高指向窄波束天線接收發射波信號與反射回波信號，再由一高速信號處理器快速地分析其都卜勒效應頻移(Doppler Frequency Shift)以計算流速，得知目標物體平均速度與速度變化數據。同時，此系統運用鎖相迴路以及迴路濾波器(Loop filter)的設計，改善控制電壓使壓控震盪器有穩定的輸出頻率，並將頻率合成器與壓控震盪器結合，形成完整的相位鎖相迴路(PLL)。此一雷達系統設計將天線、電子電路與機構組件整合在一個水密、防腐蝕之結構體，最後實現一具有高穩定度之先進水文雷達系統。最後為了驗證此雷達系統實際上運用的結果，並選定於「桃園石門大圳」、「桃園三坑清水公園水道」、及「新竹昌惠大橋」等戶外場地，執行不同水文型態、環境之運作試驗。另外，也與浮標法和手持式雷達波測速槍儀器進行比較測試。本系統量測結果與理論推算非常接近，可有效準確量測水體表面流速，在水面波紋狀況良好下，量測範圍為0.3m/s ~30m/s，適用在高流速、高流量的環境下運作。

關鍵字

連續波雷達技術；微波雷達；非接觸式量測；自動化；流量觀測；表面流速

並列摘要

A 24 GHz Continuous Wave Radar has been developed in this thesis. This CW velocity radar is applied in the non-contact measurement of the surface flow velocity of bodies of water. The radar works on Doppler Shift Principle. Radar signals reflected by the moving surface of the water are used to determine the flow velocity of the irradiated surface. The radar receives the transmitted wave signal and the reflected echo signal through a directional-narrow-beam antenna, and then quickly analyzes the Doppler effect frequency shift by a high-speed signal processor to calculate the average speed and velocity data of the moving object. Moreover, this system uses a phase-locked loop and a loop filter design to improve the control voltage so that the voltage-controlled oscillator can output a stable frequency. Finally, we make use of a frequency synthesize to combine the frequency with the VCO and TCXO so that can achieve a complete phase- locked loop (PLL). In order to verify the radar system, we chose three outdoor locations such as "Shi-men rural ditch", "San-keng Park ditch" and " Chang-hui Bridge" for field testing. Moreover, we also used floats and Stalker Pro II SVR (Handhole Surface Velocity Radar) to determine the surface velocity. Experiments indicate that the measurement results of this system are very close to the theory, which can effectively and accurately determine the surface velocity. This radar is suitable for flood events and the measurement range of this radar can be 0.3m/s ~30m/s in the case of good water ripple conditions(<3cm) .