分类： 地球科学 >> 空间物理学 提交时间： 2017-01-04
摘要： Huynen phenomenological decomposition as the first for-malized target decomposition has not been widely accepted. Huynen’s preference for scattering symmetry and regularity restricts not only the application of this decomposition but also its unification with other target dichotomies such as the Barnes-Holm decomposition and Yang decomposition. The non-uniqueness issue then arises because we may have dif-ferent dichotomies of radar targets, but we have no idea on how to select them. Recently, a unified Huynen dichotomy was developed by Li and Zhang to extend Huynen decom-position for a full preference for symmetry and regularity, non-symmetry, irregularity, as well as their couplings. The dichotomy covers all the existing dichotomies and provides an excellent discrimination of radar targets. This paper gives a concise review of the Huynen-type target dichotomies to investigate the existing concerns influencing the application of such decompositions and the corresponding coping me-thods. We hope this review will help to promote the wide acceptation of Huynen-type target dichotomies in the future.
分类： 地球科学 >> 空间物理学 提交时间： 2017-01-04
摘要： Huynen decomposition prefers the world of basic symmetry and regularity (SR) in which we live. However, it is just this preference prevents Huynen decomposition from analyzing the non-symmetric (NS) and irregular (IR) targets. The canonical Huynen dichotomy is proposed to provide two competent supplements to Huynen decomposition by developing two other target dichotomies with the scattering preferences for IR and NS. In virtue of an adaptive combination and permutation of the scattering preferences of the canonical dichotomy, a scattering preference pyramid description of the mixed scattering is developed in this paper. The pyramid is composed of three layers to reflect three different degrees of scattering randomness. Each layer is further composed of several blocks to totally indicate ten different scattering mechanisms. The excellent performance of this scheme is demonstrated by comparing it with the widely-used entropy/alpha classification, and a better discrimination of radar targets is obtained. �VDE VERLAG GMBH �Berlin �Offenbach.
分类： 地球科学 >> 空间物理学 提交时间： 2016-05-03
摘要： The RFSCAT(Rotating Fan-beam SCATterometer) is one of the two payloads of CFOSAT, the China-France Oceanography Satellite. It is a radar scatterometer designed to measure the electromagnetic back-scatter from wind roughened ocean surface. The operating frequency of the scatterometer is 13.256GHz (Ku-band) and has a swath about 1,000 kilometers. In this paper, based on the characteristics of echo signal of RFSCAT, the on-board processing of RFSCAT signal is introduced. A Doppler pre-compensation LUT and A slice division LUT are developed, and the signal processing algorithms are validated and the wind retrieval performances of RFSCAT are analyzed based on the well-developed data simulation system of CFOSAT RFSCAT.
分类： 地球科学 >> 空间物理学 提交时间： 2016-05-03
摘要： Water vapor and cloud liquid water can influence the accuracy of sea surface height that spaceborne altimeter measures. Atmospheric correction microwave radiometer (ACMR) can be used to retrieve the amount of water vapor and cloud liquid water by measuring radiation from atmosphere and earth's surface. HY-2 satellite is a Chinese satellite for ocean dynamic environmental monitoring. ACMR is one payload of HY-2 satellite. Up to now, ACMR has been in operation for more than three years. In-orbit system stability of three years is assessed. The data of ACMR brightness temperature are matched to that of ECMWF wet tropospheric path delay in same space and time. The water vapor and cloud liquid water retrieval algorithm is derived The wet tropospheric path delay deviations are less than 1.5cm. Brightness temperatures and path delay of ACMR were compared with that of AMR. The average and standard deviations of wet tropospheric path delay are 1.27mm and 0.68mm.
分类： 地球科学 >> 空间物理学 提交时间： 2017-03-10
摘要： In PolSAR data processing, deorientation operation is often necessary. The existing deorientation method uniformly deorients all the sub-scatterers of a resolution cell with one orientation angle. For high entropy situation, the sub-scatterers have diverse OAs, and the effect of the existing method is unsatisfactory. A novel deorientation method is proposed to well treat the high entropy situation. Cloude's eigen-decomposition to the coherency matrix is first carried out. The three eigenvectors are then separately deoriented with their own orientation angles. Experiments demonstrate that the proposed method is suitable for extraction of urban regions, especially for extraction of oriented urban regions. �VDE VERLAG GMBH �Berlin �Offenbach.
分类： 地球科学 >> 空间物理学 提交时间： 2017-03-10
摘要： Man-made buildings detection is important in land use supervision and land control applications. Generally, polarimetric synthetic aperture radar (PolSAR) data are processed to detect buildings well. But for some buildings which are not aligned with the radar track, these buildings are usually incorrectly recognized as forest, because the oriented buildings produce additional cross-polarization. Polarimetric interferometric SAR (PolINSAR) acquires two measurements with a spatial baseline or a temporal baseline. For the PolINSAR with a temporal baseline i.e., the repeat pass PolInSAR, the two polarimetric measurements are sensitive to targets' temporal variations during the time. The buildings, regardless of the orientations, have high coherence, while some natural targets have low coherence. A novel parameter is proposed here, which represents the mean PolINSAR coherence and can be utilized to distinguish between buildings and some natural targets. The parameter is based on the coherence optimization theory of Cloude and Papathanassiou, and is the mean of the three optimal coherences with three pseudo-probabilities. Based on this new parameter and the SPAN, a method to detect buildings is further proposed. The excellent performance of the proposed method on buildings extraction is demonstrated by processing German Aerospace Center (DLR) L-band E-SAR repeat pass PolINSAR data of Oberpfaffenhofen area.
分类： 地球科学 >> 空间物理学 提交时间： 2017-03-10
摘要： Imaging period is an important consideration to geostationary interferometric microwave sounder (GIMS) when mapping fast changing target such as typhoon. GIMS simulation system with near real case observation target can evaluate system performance in different system configurations and thus help determine the optimal imaging period. In this paper, GIMS simulation system using MATLAB and near real case observation modeled by FNL/WRF/RTTOV method has been used to analyze the effect of imaging period on image quality. System simulation results for each frequency channel will be presented and analyses of imaging period's effect on image quality will also be given. �2016 IEEE.
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