Long-time non-contact water level measurement with a 5.8-GHz DC-coupled interferometry radar

Flooding caused by tropical cyclones, tsunami, and many other phenomena is one type of natural disaster that occurs all around the world. While these disasters cannot be prevented, the communities can be made more resilient and damages caused by them to lives and infrastructure can be minimized by developing early warning systems. Microwave-based systems provide a non-contact measurement setup to monitor water level, thus requiring low maintenance and operation costs. In this paper, a DC-coupled 5.8-GHz interferometry radar was designed and tested by observing water level in a barrel, which had water poured in and drained out over a long-time period. By adding more gains to the RF chain and removing the gain in the baseband, the proposed water-level monitoring radar system eliminates the requirement of complex DC tuning structure in the previous works. The experiment demonstrated that the proposed water-level monitoring radar system was able to accurately measure the relative position of water with mm-accuracy.