基于AR模型的多普勒散射计回波功率谱估计  

An Echo Power Spectral Density Estimation Method Based on AR Model for Doppler Scatterometter

作　　者：孙伟峰[1] 李雯[1] 范陈清 贾晨 王青[3] SUN Weifeng;LI Wen;FAN Chenqing;JIA Chen;WANG Qing(College of Oceanography and Space Informatics,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Remote Sensing Office of the First Institute of Oceanography,Ministry of Natural Resources,Qingdao,Shandong 266061,China;College of Control Science and Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,China)

机构地区：[1]中国石油大学(华东)海洋与空间信息学院,山东青岛266580 [2]自然资源部第一海洋研究所遥感室,山东青岛266061 [3]中国石油大学(华东)控制科学与工程学院,山东青岛266580

出　　处：《遥感信息》2023年第2期40-47,共8页Remote Sensing Information

基　　金：国家自然科学基金项目(62071493)。

摘　　要：当采样点数少或流速较小时,采用周期图法估计的多普勒散射计(Doppler scatterometer,DopSCAT)回波功率谱分辨率低,多普勒频移提取精度低。对此,提出了一种基于自回归(autoregressive,AR)模型的DopSCAT回波功率谱估计方法。该方法为DopSCAT回波信号建立含有未知参数的AR模型,采用赤池信息量准则自适应确定模型的最优阶数;对定阶后的AR模型采用Burg算法计算模型参数,利用得到的AR模型估计回波功率谱;对功率谱进行峰值检测提取多普勒频移计算径向流,采用两个观测方位向的径向流合成得到海面流场。利用OSCAR海流数据进行了回波功率谱估计与海流反演实验。分析结果表明,与周期图法相比,该方法能够显著提高回波功率谱分辨率和多普勒频移的提取精度,进而提高了海流的反演精度。The spectral resolution of Doppler scatterometer(DopSCAT)echo power estimated by Periodogram is low for limited number of sampling points and small current velocities,which leads to the low accuracy of Doppler frequency shift extraction.In order to address this problem,an echo power spectral density estimation method based on autoregressive(AR)model is proposed.An AR model with unknown parameters is first established for the echo signals of Doppler scatterometer,and the akaike information criterion is used to determine the optimal model order.Then,Burg algorithm is used to calculate the parameters of the AR model after the order is determined,and the echo power spectral density can be obtained by using the AR model.Finally,the accurate Doppler frequency shift is extracted by detecting spectral peaks to compute radial velocity,and combining radial current velocities in two observed directions to obtain the sea surface current field.The echo power spectral density estimation experiments and the ocean current inversion experiments are carried out by using the ocean surface current analyses real-time(OSCAR)data.The results show that compared with the periodogram,the proposed method can improve the resolution of the echo power spectrum and the extraction accuracy of doppler frequency shift,and thus improve the inversion accuracy of ocean current effectively.

关 键 词：多普勒散射计 海流反演 回波功率谱 AR模型 多普勒频移 

分 类 号：TP70[自动化与计算机技术—检测技术与自动化装置]