River Surface Analysis and Characterization Using FMCW Radar

Abstract

Today’s warning systems for floods or droughts require sensor applications that provide a vast array of information. Current systems provide insight into either the water level or the river velocity. In order to obtain additional parameters for the characterization of the flow behavior in a noncontact manner, a frequency-modulated continuous-wave radar with chirp sequence is used. Since these sensors provide range and velocity information but also enable gathering of additional parameters. The presented measurements in this contribution were performed at four different rivers with a commercially available radar sensor. The results of the classical postprocessed 2-D fast Fourier transform are used as basis for an imagewise processing approach to obtain additional features for classifying the behavior of the river surface. For this purpose, the framewise enveloping velocities are depicted in a time sequence. Due to processing the detected reflection patterns in relation to time, a characteristic pattern for river flow profiles can be extracted. By reducing the information using time averaging, characteristic features for different flows can be extracted from the spatial envelope velocity distribution. In particular, the resulting insights lead to characteristic features for single flow distributions that enable novel monitoring systems with new possibilities to classify rivers using radar sensors.