We demonstrate a 24 GHz hydrology radar system. The continuous‐wave Doppler radar is capable of noncontact and wide‐range surface‐flow velocity detection in various scenarios. The radar receives the reflected echo signal through a directional narrow‐beam antenna. After amplification and demodulation by the proposed low‐noise amplifier and the subharmonic down‐conversion mixer, respectively, the Doppler frequency‐shift is analyzed by the digital signal processing (DSP) module for estimation of the water flow velocity. Moreover, for water level detection, a phase‐locked loop with micro control unit (MCU)‐controlled division ratio is included in the RF module for generating a stable and tunable (or frequency modulation) 24‐GHz‐band transmitting signal with low phase noise. To verify the radar system, outdoor field tests have been conducted. The measured results are consistent with the theoretical values, and the results of both the float method and the commercial handheld (Stalker Pro II) surface velocity radar. In the condition of water ripple lower than 3 cm, the radar functions well for flow speed range of 0.3 ~ 34.6 m/s. Overall, the hydrology radar is suitable for surface‐flow velocity detection (especially in bad weather) and water resource management (such as water‐level detection).

中文翻译：

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24 GHz水文雷达系统，能够在水资源管理应用中进行大范围的表面速度检测

我们演示了一个24 GHz水文雷达系统。连续波多普勒雷达能够在各种情况下进行非接触式和宽范围地表流速检测。雷达通过定向窄波束天线接收反射的回波信号。分别通过拟议的低噪声放大器和亚谐波下变频混频器进行放大和解调后，通过数字信号处理（DSP）模块分析多普勒频移，以估算水流速。此外，对于水位检测，RF模块中包括一个具有微控制单元（MCU）控制的分频比的锁相环，用于生成稳定且可调（或频率调制）的24 GHz频段低相位发射信号噪声。为了验证雷达系统，已进行了室外现场测试。测量结果与理论值，浮法和商用手持式（Stalker Pro II）表面速度雷达的结果均相符。在水波纹低于3 cm的情况下，雷达在0.3〜34.6 m / s的流速范围内运行良好。总体而言，水文学雷达适用于地表流速检测（尤其是在恶劣天气中）和水资源管理（例如水位检测）。