MUSIC算法提取海洋表面径向流方位的信号预处理

Signal Preprocessing for Bearing Determination of Ocean Surface Radial Current Mapping Based on MUSIC

阐述从高频地波雷达海洋回波反演海洋表面流中 ,使用 MUSIC算法提取径向流方位必须的信号预处理。海洋回波首先经线性调频中断连续波 (FMICW)波形解调 ,分成不同距离元海洋回波。在各通道独立接收的海洋回波谱分析的基础上 ,针对每一距离元进行通道幅度的软件校准。接着从每一距离元合成的海洋回波多普勒功率谱中 ,分离包含海洋表面流信息的一阶谱区 ,再依据“局部噪声阈值扣除法”确定其中的可用信号。最终由 MU SIC算法提取每一可用信号 (其频偏对应径向流速 )的多个存在方位 ,从而获得海洋表面径向流场的完整信息。本文阐述预处理使用的各种算法、效果及实测信号的部分处理结果。

In this paper, signal preprocessing for bearing determination of ocean surface radial current mapping by HF ground wave radar based on MUSIC is investigated. oceant surface radial current mapping involves determination of the current velocities and the azimuths and range of the sea cells on which the surface currents reside. Sea echoes are firstly FMICW- demodulated to separate different range cells of sea echoes. Based on the sea echo Doppler power spectra of every channel, channel amplitude responses are software calibrated for every range cell. The first-order spectra, which contain ocean surface current information, are separated afterwards from the synthesized sea echo Doppler power spectra of every range cell. At last, the usable spectral bins for extracting ocean surface radial currents are picked out by 'local noise threshold filtration method'. The ocean echo signals at these spectral bins are then processed by MUSIC algorithms to obtain the azimuths of every radial current. So that the whole information for ocean surface radial current mapping is obtained. The set of algorithms in the procedure are investigated in this paper, as well as their effects and part of actual measurement results.