Experimental Investigation of Ocean Wave Measurement Using Short-Range K-Band Radar: Dock-Based and Boat-Based Wind Wave Measurements

Abstract

In this paper, an ocean wave measurement technique and a newly developed short-range K-band radar are tested. In previous work, the technique and its feasibility were studied based on numerical simulations and wave tank experiments, while its performance at sea was still unknown. Surface current, Stokes drift, and wave breaking can greatly complicate interpreting radar backscatters. The feasibility of the technique needed to be further investigated with sea experiments. Experiments were carried out at a stationary site and from a moving platform. The short-range K-band radar transmitted continuous wave and received backscatters at low-grazing angles. The Bragg-scattering from the radar’s effective footprint dominated the backscatters. The Doppler shift frequency of the Bragg-scattering was attributed to the phase velocity of Bragg waves and modulated by the surface motions induced by current, Stokes drift, platform, and gravity waves. These sources of the Doppler shift frequency were analyzed, and the components induced by wind waves were successfully retrieved and converted into wave spectra that were consistent with the measurements of wave rider buoy. The experimental investigation further validated the feasibility of using short-range K-band radar to measure ocean waves.

High-Resolution Radar Sensing Sea Surface States During AMK-82 Cruise

“…When coherent radar operates from a board of moving vessels, it is necessary to consider the vessel velocity [16]. A corresponding method of determining the wave height from the side of a moving vessel using Doppler measurements is proposed in [17]. For DMR MRS-1000, the range of unambiguously measured velocities is ±2.2 m/s, which is insufficient for measuring the velocities of the sea surface from a moving vessel.…”

A Feasibility Study of Nearshore Bathymetry Estimation via Short-Range K-Band MIMO Radar

“…Recently, short-range K-band (SRK-band) radars have been proposed to estimate the sea state in very nearshore regions [31][32][33][34]. These systems have a short-range coverage, which typically extends up to a few hundred meters.…”

Retrieval of Sea Surface Currents and Directional Wave Spectra by 24 GHz FMCW MIMO Radar

“…More recently, the use of SRK-band radars has been proposed for sea state monitoring [26], [27], [28]. These TGRS-2022-02841.R1 systems operate in the 18-27 GHz frequency band, i.e.…”

“…The estimation methodology was validated through numerical simulations and experiments carried out in a tank with regular waves generated under ideal conditions. Later in [28], the same radar was tested to measure the spectra of wind waves at sea. Note that the aforementioned systems are used to monitor the sea state by pointing the radar in the direction of the incoming wave and local wind.…”