Radar-Based Water Detection Device for Highly Accurate Real-Time Measurements

Small, Low-Power, Wireless Sensor Detects Water Elevation Changes and Streams Continuous Data to a Local PC or Base Station

This DC-coupled, continuous-wave Doppler radar sensor can accurately and effectively measure water flow data and wirelessly transmit the data to a local station. The device can track sub-millimeter water displacement and distance measurement in time including water surface elevation in tidal zones, beach run-up, and storm surge elevation near structures. Traditional water level gauging techniques involve a massive stationhouse with large equipment, which is costly to purchase and to maintain. Other alternative methods include lasers, ultrasound, and radar. However, laser sensors are costly and difficult to install while the ultrasonic sensors have inaccurate measurements due to long wavelength resolution. Available radar gauging techniques include pulse radar and frequency modulated continuous wave (FMCW) radar, both of which suffer from relative inaccuracy. Researchers at the University of Florida have developed an accurate and power-efficient water-monitoring sensor. The sensor can run on four AA batteries for up to two hours of continuous sampling and wirelessly transmit data to a local computer or station.

Application

Wireless and low-cost radar Doppler sensor that accurately measures water surface elevation and characteristics in real time

Advantages

• Uses DC-coupled continuous wave Doppler radar, maximizing measurement accuracy and resolution
• Is compact and uses low power, minimizing costs
• Has embedded microprocessor, enabling data processing at the sensor location and wireless transmission to a computer or base station
• Uses noncontact measurement approach, eliminating interference
• Can group sensors to work as a network, enabling assessment of spatial variability in tidal zones and run-up regions

Technology

This DC-coupled continuous-wave Doppler radar sensor is capable of detecting water elevation changes in real time when installed up to several meters above the water surface. The radar device consists of two patch antennae, one transmitter and one receiver. The data collected is wirelessly transmitted to the base station or local computer. The sensor is smaller than a tissue box, uses low power, and operates wirelessly while reaching sampling rates up to 40 Hz. When multiple wireless radar sensors collaborate as a network, they can increase the data quality even more than that of a single sensor.