一种用于海洋要素反演的机载SAR多普勒中心偏移计算方法  

Research on Calculation Method of Doppler Centroid Shift from Airborne Synthetic Aperture Radar for Ocean Feature Retrieval

作　　者：赵现斌 严卫 艾未华 陆文 马烁 ZHAO Xianbin;YAN Wei;AI Weihua;LU Wen;MA Shuo(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学气象海洋学院

出　　处：《雷达学报（中英文）》2019年第3期391-399,共9页Journal of Radars

基　　金：国家自然科学基金(41575028,41705007,41605016);湖南省自然科学基金(2019JJ50719);国防科技大学科研计划项目(ZK17-03-51)~~

摘　　要：多普勒中心偏移是合成孔径雷达(SAR)反演海面风场、海表流场的重要参数。该文针对机载正侧视提出一种多普勒中心偏移计算方法,分别利用载机运动状态数据和海洋探测回波数据计算多普勒中心频率,再作差求解多普勒中心偏移,并在多普勒谱分析中加入小波分析去除噪声的影响来提高计算精度。以CDOP经验模型计算结果作为比对真值,机载SAR飞行探测试验结果表明,9组探测数据多普勒中心偏移计算误差的绝对值均小于2 Hz,均方根误差为1.4 Hz,满足海洋环境要素反演的精度要求。实验表明高精度的平台运动状态数据和探测回波数据是多普勒中心偏移海洋应用的关键。Doppler center shift is an important parameter for Synthetic Aperture Radar(SAR)to retrieve ocean surface wind field and ocean surface current field.We present a calculation method of Doppler centroid shift for airborne side-looking SAR.We compute Doppler centroid frequency by aircraft motion status data and ocean detection echo data respectively,and make difference to solve the Doppler centroid shift.In order to remove the influence of noise,we add wavelet analysis in Doppler spectrum analysis method to improve Doppler centroid frequency accuracy from ocean detection echo data.We carry out flight detection experiment by airborne SAR to obtain the Doppler centroid shift,while put buoy wind direction and wind speed in detection area into CDOP geophysical model function to simulate the Doppler centroid shift as compared to the validation true value.Flight detection results of 9 group data show that the calculation error absolute value of Doppler centroid shift are less than 2 Hz,and the RMS error is 1.4 Hz.It is meets the accuracy requirements of marine environmental factors retrieval,and proves the effective of Doppler centroid shift calculation method.In practical applications,the accuracy of Doppler centroid shift calculation is the key to the application of marine environment research,which requires high-precision platform motion data and sounding echo data to ensure application value.

关 键 词：机载正侧视合成孔径雷达 多普勒中心偏移 计算方法 多普勒中心频率 

分 类 号：TP751.1[自动化与计算机技术—检测技术与自动化装置] P738[自动化与计算机技术—控制科学与工程]