Overview: Simple, fast, accurate, reliable and stable channel and river measurement devices have always been the pursuit of flow measurement experts from all over the world. Due to the limitations of science and technology, this problem has never been solved. However, in recent years, the situation has been fundamentally changed after the United States applied acoustic Doppler multi-point profile flow velocity measurement technology to this field. The flow measurement system designed by our company using the FLOW series of acoustic Doppler flow rate meters has been widely used in flow and flow velocity measurements in water conservancy, environmental protection, and urban water supply and drainage. The Doppler effect is named in honor of the Austrian physicist Christian Johann Doppler. In the field of acoustics, when there is relative motion between the sound source and the receiver (i.e., the probe and the reflector), the echo The frequency will change, and this change in frequency…