Optimal aperture synthesis radar imaging
Optimal aperture synthesis radar imaging
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DOI：
10.1029/2005rs003383
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发表时间：
2006-04
期刊：
影响因子：
1.6
通讯作者：
D. Hysell;J. Chau
中科院分区：
文献类型：
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作者：
D. Hysell;J. Chau
多年来，孔径合成雷达成像一直用于研究Jicamarca和其他地方电离层等离子体不规则性的相干后向散射。感兴趣的现象包括赤道传播F、150公里回波、赤道电喷流、范围传播的流星轨迹和中间层回波。通过积分变换，将所需要的图像与间隔接收器数据在数学上联系起来，但直接反演通常是不切实际的或次优的。我们转而采用统计逆理论，努力在数据反演中充分利用所有可用的信息。Jicamarca使用的成像算法是基于为射电天文学开发的MaxEnt方法的实现。它的策略是将候选图像的空间限制为那些正确定的，与实验置信度限所要求的数据一致的图像；平滑（在某种意义上）；也是这类可能解中最有代表性的。近年来对该算法进行了改进：(1)在先验概率中加入天线辐射方向图；(2)在约束条件中估计并包含完整的误差协方差矩阵。使用Jicamarca新的28基线电射流数据对修订后的算法进行了评估。
Aperture synthesis radar imaging has been used to investigate coherent backscatter from ionospheric plasma irregularities at Jicamarca and elsewhere for several years. Phenomena of interest include equatorial spread F, 150‐km echoes, the equatorial electrojet, range‐spread meteor trails, and mesospheric echoes. The sought‐after images are related to spaced‐receiver data mathematically through an integral transform, but direct inversion is generally impractical or suboptimal. We instead turn to statistical inverse theory, endeavoring to utilize fully all available information in the data inversion. The imaging algorithm used at Jicamarca is based on an implementation of the MaxEnt method developed for radio astronomy. Its strategy is to limit the space of candidate images to those that are positive definite, consistent with data to the degree required by experimental confidence limits; smooth (in some sense); and most representative of the class of possible solutions. The algorithm was improved recently by (1) incorporating the antenna radiation pattern in the prior probability and (2) estimating and including the full error covariance matrix in the constraints. The revised algorithm is evaluated using new 28‐baseline electrojet data from Jicamarca.