Experiment with the X-Band Radar in the Altimetric Mode Over the Volga River: A Backscattering From an Ice and a Water Surface

Microwave radars are used to classify the type of reflective surface, and usually the power or spectral characteristics of the reflected signal are analyzed as an information parameter. In this study, to classify the type of scattering surface (ice/water), it is proposed to use the waveform of the reflected pulse. It is expected that a significant difference in the statistical characteristics of the ice cover and the rough water surface will manifest itself in the waveform of a reflected pulse. To check this assumption, an experiment was performed on the Nizhny Novgorod cable car, which crosses the Volga river. An altimeter with a knife-like antenna beam (3.6° x 30°) was mounted on a technological trolley and performed sensing vertically downwards while moving over ice and open water. A comparison of the reflected pulses showed that for the ice cover the trailing edge of the reflected pulse is shorter than for the open water with waves. This is due to the difference in the mean square slopes (mss) of the ice cover and the water surface and, thus, the waveform of the reflected pulse can be used to determine the type of the scattering surface.