基于一阶海洋回波的HF-SAR提取表层海流性能分析

将合成孔径技术用于高频地波雷达，以实现单站提取表层海流，对于降低观测成本、提高效率具有重要意义。但现有的高频合成孔径雷达(HF-SAR)信号模型是基于理想点目标的，而未考虑海域分辨单元的Bragg散射效应。针对这一问题，基于一阶海洋回波理论，该文提出了用HF-SAR提取表层海流的改进的信号模型，并分析了Bragg散射对HF-SAR方位向回波的影响。然后针对方位向回波信号的特点，给出了相应的速度估计算法。最后通过蒙特卡洛仿真分析了HF-SAR对指定海域分辨单元的速度估计性能，结果显示对于流速和流向的估计精度能够满足工程应用的要求，这表明用HF-SAR提取表层海流是可行的。

Performance Analysis of Surface Current Extraction by HF-SAR Based on First Order Sea Echo

It is important to apply synthetic aperture technique to High Frequency Surface Wave Radar (HFSWR), and thus to implement surface current extraction by a single site, for the sake of reducing observation cost and improving efficiency. However the existing signal model of High Frequency SAR (HF-SAR) is based on theoretic point targets, and therefore the Bragg scattering effect of sea resolution cells is not considered. To solve this problem, an improved signal model of surface current extraction by HF-SAR is presented based on first order sea echo, and the effect of Bragg scattering to the azimuth echo of HF-SAR is analyzed. Then a velocity estimation algorithm is designed according to the signal features of the azimuth echo. Finally the velocity estimation performance of HF-SAR is analyzed on a specified resolution cell by Monte Carlo simulation. Simulation results show that the estimation precision of velocity and direction meets the requirements of engineering application, which indicates that it is feasible to extract surface current by HF-SAR.