Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results

Millimeter-wave (MMW) radar is capable of providing high temporal–spatial measurements of the ocean surface. Some topics, such as the characterization of the radar echo, have attracted widespread attention from researchers. However, most existing research studies focus on the backscatter of the ocea...

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Main Authors: Qinghui Xu, Chen Zhao, Zezong Chen, Sitao Wu, Xiao Wang, Lingang Fan
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Remote Sensing
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Online Access:https://www.mdpi.com/2072-4292/17/1/116
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author Qinghui Xu
Chen Zhao
Zezong Chen
Sitao Wu
Xiao Wang
Lingang Fan
author_facet Qinghui Xu
Chen Zhao
Zezong Chen
Sitao Wu
Xiao Wang
Lingang Fan
author_sort Qinghui Xu
collection DOAJ
description Millimeter-wave (MMW) radar is capable of providing high temporal–spatial measurements of the ocean surface. Some topics, such as the characterization of the radar echo, have attracted widespread attention from researchers. However, most existing research studies focus on the backscatter of the ocean surface at low microwave bands, while the sea surface backscattering mechanism in the 77 GHz frequency band remains not well interpreted. To address this issue, in this paper, the investigation of the scattering mechanism is carried out for the 77 GHz frequency band ocean surface at small incidence angles. The backscattering coefficient is first simulated by applying the quasi-specular scattering model and the corrected scattering model of geometric optics (GO4), using two different ocean wave spectrum models (the Hwang spectrum and the Kudryavtsev spectrum). Then, the dependence of the sea surface normalized radar cross section (NRCS) on incidence angles, azimuth angles, and sea states are investigated. Finally, by comparison between model simulations and the radar-measured data, the 77 GHz frequency band scattering characterization of sea surfaces at the near-nadir incidence is verified. In addition, experimental results from the wave tank are shown, and the difference in the scattering mechanism is further discussed between water surfaces and oceans. The obtained results seem promising for a better understanding of the ocean surface backscattering mechanism in the MMW frequency band. It provides a new method for fostering the usage of radar technologies for real-time ocean observations.
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id doaj-art-62a71b2d9aba4d5eacc1f4a9f40ff606
institution Kabale University
issn 2072-4292
language English
publishDate 2025-01-01
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series Remote Sensing
spelling doaj-art-62a71b2d9aba4d5eacc1f4a9f40ff6062025-01-10T13:20:16ZengMDPI AGRemote Sensing2072-42922025-01-0117111610.3390/rs17010116Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary ResultsQinghui Xu0Chen Zhao1Zezong Chen2Sitao Wu3Xiao Wang4Lingang Fan5School of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaSchool of Electronic Information, Wuhan University, Wuhan 430072, ChinaBeijing Institute of Radio Measurement, Beijing 100854, ChinaMillimeter-wave (MMW) radar is capable of providing high temporal–spatial measurements of the ocean surface. Some topics, such as the characterization of the radar echo, have attracted widespread attention from researchers. However, most existing research studies focus on the backscatter of the ocean surface at low microwave bands, while the sea surface backscattering mechanism in the 77 GHz frequency band remains not well interpreted. To address this issue, in this paper, the investigation of the scattering mechanism is carried out for the 77 GHz frequency band ocean surface at small incidence angles. The backscattering coefficient is first simulated by applying the quasi-specular scattering model and the corrected scattering model of geometric optics (GO4), using two different ocean wave spectrum models (the Hwang spectrum and the Kudryavtsev spectrum). Then, the dependence of the sea surface normalized radar cross section (NRCS) on incidence angles, azimuth angles, and sea states are investigated. Finally, by comparison between model simulations and the radar-measured data, the 77 GHz frequency band scattering characterization of sea surfaces at the near-nadir incidence is verified. In addition, experimental results from the wave tank are shown, and the difference in the scattering mechanism is further discussed between water surfaces and oceans. The obtained results seem promising for a better understanding of the ocean surface backscattering mechanism in the MMW frequency band. It provides a new method for fostering the usage of radar technologies for real-time ocean observations.https://www.mdpi.com/2072-4292/17/1/116millimeter waveocean observationslow incidencequasi-specular scattering
spellingShingle Qinghui Xu
Chen Zhao
Zezong Chen
Sitao Wu
Xiao Wang
Lingang Fan
Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
Remote Sensing
millimeter wave
ocean observations
low incidence
quasi-specular scattering
title Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
title_full Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
title_fullStr Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
title_full_unstemmed Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
title_short Characterization of 77 GHz Radar Backscattering from Sea Surfaces at Low Incidence Angles: Preliminary Results
title_sort characterization of 77 ghz radar backscattering from sea surfaces at low incidence angles preliminary results
topic millimeter wave
ocean observations
low incidence
quasi-specular scattering
url https://www.mdpi.com/2072-4292/17/1/116
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AT chenzhao characterizationof77ghzradarbackscatteringfromseasurfacesatlowincidenceanglespreliminaryresults
AT zezongchen characterizationof77ghzradarbackscatteringfromseasurfacesatlowincidenceanglespreliminaryresults
AT sitaowu characterizationof77ghzradarbackscatteringfromseasurfacesatlowincidenceanglespreliminaryresults
AT xiaowang characterizationof77ghzradarbackscatteringfromseasurfacesatlowincidenceanglespreliminaryresults
AT lingangfan characterizationof77ghzradarbackscatteringfromseasurfacesatlowincidenceanglespreliminaryresults