Radar water level gauge is a non-contact hydrological monitoring device based on the principle of electromagnetic wave reflection, mainly used for real-time and accurate measurement of key parameters such as water level, flow velocity, and flow rate in hydraulic engineering. Its core working principle is to emit high-frequency electromagnetic waves (such as 24GHz, 26GHz, or 80GHz frequency bands) and receive reflected signals from the water surface. The electromagnetic wave propagation distance is calculated using time difference or frequency difference methods to determine the water level height. For example, frequency modulated continuous wave (FMCW) radar achieves millimeter level accuracy by measuring the frequency difference between the transmitted and reflected waves, while pulse radar calculates distance based on the time difference of flight.