Millimeter-Wave Radar-Based Three-Dimensional Sea-Surface Wavefield Reconstruction From Sparse Point Clouds

Abstract

Wavefield detection is closely linked to the safety development of maritime low-altitude economic activities, such as providing wave parameters for offshore platforms and supporting marine surveying and inspection. This technology also serves as a key generic technology for optimizing various maritime operations. Accordingly, this article presents a novel research on employing 4-D millimeter-wave (mmWave) radar mounted on uncrewed aerial vehicle (UAV) to achieve high-resolution 3-D wavefield detection. To address the challenge of sparse distribution in the sea-surface point clouds, which are derived from sea clutter obtained by mmWave radar, linear wave theory and sparse representation are integrated to facilitate the extraction of wave model parameters. This process culminates in reconstruction of the wavefield within a specified detection range. The results of numerical simulations have demonstrated the feasibility and effectiveness of this method in multiple aspects. During sea trials, UAV-captured sea-surface images and instantaneous wave height data measured by surrounding buoys are employed as reference data for comparative wavefield analysis. Preliminary findings show that the reconstructed wavefield is highly consistent with the parameters inverted from UAV nadir videos with respect to both sea-surface characteristics and wave statistical parameters. Compared with traditional methods, this approach features flexible working range, rapid response to wave measurement, and low operational and maintenance costs. Consequently, it is expected to be a viable solution for wavefield detection that balances flexibility and measurement accuracy.