Doppler spectra of electromagnetic wave scattered from an object flying above time-varying nonlinear sea surfaces

ABSTRACT

Doppler spectra of electromagnetic wave scattered from an object flying above time-varying nonlinear sea surfaces are investigated by utilizing a hybrid algorithm combining method of moments (MoM) and Kirchhoff approximation (KA). The “choppy wave” model is employed for describing nonlinear hydrodynamic interactions between ocean waves. Doppler spectra of scattered wave are simulated and analyzed for different incidence angles, target velocities, target heights, sea states as well as sea surface models, and an obvious broadening of Doppler spectrum is observed due to the coupling scattering between the flying target and rough sea surfaces. In comparison with the normalized radar cross section, Doppler spectra of scattered wave have the advantage of extracting information regarding target flying above dynamic sea surfaces. This study is of great value for the analysis of coupling scattering between flying target and rough sea surface as well as for the detection low-flying target in sea clutter environment.

KEYWORDS:

• Doppler spectrum
• electromagnetic scattering
• nonlinear sea surface
• hybrid method
• method of moments (MoM)
• Kirchhoff approximation (KA)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported in part by the National Natural Science Foundation of China (Grant Nos. 61701428, 61861043, 61801416), in part by the Natural Science Basic Research Plan in Shaanxi Province of China (Grant Nos. 2019JQ-120, 2019JM-363 and 2019JQ-237), in part by the Scientific Research Foundation of Yanan University (Grant Nos. YDBK2016-17, YDY2017-06 and YDY2018-10), in part by the Open Foundation of Fudan University Key Laboratory for Information Science of Electromagnetic Waves (MoE) (Grant number EMW201910), and in part by Yan'an Science and Technology Research and Development Plan Project (Grant number 2018KG-01).

Notes on contributors

Peng-Ju Yang

Peng-Ju Yang received his PhD degree in radio science from Xidian University, Xi'an, China, in 2016, and he is currently with School of Physics and Electronic Information, Yanan University. His research interests include computational electromagnetics, electromagnetic scattering from rough surfaces, and ocean remote sensing.

Rui Wu

Rui Wu received her BS degree in degree in radio science from Xidian University, Xi'an, China, in 2012, and she is currently with School of Physics and Electronic Information, Yanan University. Her research interests include electromagnetic scattering from rough surfaces and its applications in remote sensing.

Xin-Cheng Ren

Xin-Cheng Ren received his PhD degree in radio science from Xidian University, Xi'an, China, in 2008, and he is currently with School of Physics and Electronic Information, Yanan University. His research interests include electromagnetic wave propagation and scattering in complex system, computational electromagnetics, and fractal electrodynamics.

Yu-Qiang Zhang

Yu-Qiang Zhang received his PhD degree in radio science from Xidian University, Xi'an, China, in 2010, and he is currently with School of Physics and Electronic Information, Yanan University. His research interests include computational electromagnetics in time-domain, electromagnetic scattering from rough surfaces, high performance computing in remote sensing and computational electromagnetics.

Ye Zhao

Ye Zhao received her BS degree and PhD degree from Xidian University in 2011, and 2016, respectively. She is currently with School of Physics and Electronic Information, Yanan University. Her research interests include electromagnetic scattering from rough surfaces and SAR imaging of complex scene.