摘要
该文针对经典双尺度海面模型不能有效分析高海况和低掠射角条件下的非Bragg散射问题,在模型中引入调频率描述多普勒频率的变化,提出了一种更符合工程实际的1维时变海面散射模型。然后,通过计算改进模型的海面平均散射功率,得到了时变海面的角度散射特性。其次,研究了改进模型的分数阶功率谱(FPS)特性,得出在分数阶Fourier变换(FRFT)域,海面散射信号的功率谱由多分量冲激信号组成,其在FRFT域的位置可用于估计模型的频率参数。最后,采用X波段实测海面回波数据对改进模型进行验证,并讨论了入射波长和变换角对FPS的影响,仿真结果表明该模型适合分析和提取时变海面回波的频率变化及多普勒频移。
To investigate the problem of classical two-scale sea surface model, which can not effectively analyze the non-Bragg scattering at high sea state and low grazing angle, a more practical scattering model for one-dimension （l-D） time-vaxying sea surface is adopted, in which a chirp parameter is employed to describe the changes of Doppler frequency. Then, the angular scattering characteristic of the improved model is investigated based on the mean scattered power. Next, the Fractional Power Spectrum （FPS） of the improved model is analyzed, which shows that the FPS of the scattered field is found to be distributed as sum of impulse signals and the peaks are relative to the frequency parameters of the improved model. Finally, X-band real sea data is used for verification and the influences of incident wavelength and transform angle on the FPS axe discussed. The results prove that the improved model is suitable for the analysis and extraction of the frequency changes and Doppler shift for the time-vaxying sea surface.
出处
《电子与信息学报》
EI
CSCD
北大核心
2012年第8期1897-1904,共8页
Journal of Electronics & Information Technology
基金
国家自然科学基金(60802088
61179017)
航空科学基金(20095184004)
"泰山学者"建设工程专项经费资助课题
