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An InSAR scattering model for multi-layer snow based on QuasiCrystalline Approximation(QCA) theory

Science China Earth Sciences 2018年第8期61卷 1112-1126页

作者： Zhen LI Zhixian LI Bangsen TIAN Jianmin ZHOU Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100094 China University of Chinese Academy of Sciences Beijing 100049 China

Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. In SAR(Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using In SAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the In SAR scattering model for single-layer snow has been fully studied;however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA(Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an In SAR volumetric correlation of different types of multi-layer snow at the X band(9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also *** model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization In SAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization In SAR volumetric correlation and more conducive to the development of a parameter-inve

关键词： Snow InSAR QCA scattering model

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A novel synthetic aperture radar scattering model for sea surface with breaking waves

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Acta Oceanologica Sinica 2022年第4期41卷 138-145页

作者： Xiaochen Wang Yuxin Hu Bing Han Wei Tian Chunhua Zhang Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Technology in Geo-spatial Information Processing and Application System Chinese Academy of SciencesBeijing 100190China The box51111 Beijing 100190China

In this study a novel synthetic aperture radar(SAR)scattering model for sea surface with breaking waves is *** with existing models,the proposed model considers an empirical relationship between wind speed and wave breaking scattering to present the contribution of wave ***,the scattering weight factor p,and wave breaking rate q,are performed to present the contribution of the quasi-specular scattering term,Bragg scattering term,and wave breaking scattering term to the total scattering from the sea *** explore the modeling accuracy of sea-surface scattering,a simulated normalized radar cross-section(NRCS)and measured NRCS are *** proposed model generated the simulated NRCS and a matching GF-3 dataset was used for the measured *** was revealed that the performance of the VV polarization of our model was much better than that of HH polarization,with a correlation of 0.91,bias of-0.14 dB,root mean square error(RMSE)of 1.26 dB,and scattering index(SI)*** addition,the novel model is explored and compared with the geophysical model of CMODs and satellite-measured NRCS from GF-3 SAR wave mode *** an incidence angle 40°–41°,the relationship between the NRCS and wind speed,relative wind direction is *** with the SAR-measured NRCS,the performance of VV polarization was much better than HH polarization,with a correlation of 0.99,bias of-0.25 dB,RMSE of 0.64 dB,and SI of-0.04.

关键词： synthetic aperture radar scattering model sea surface wave breaking

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Bi-Spectrum scattering model for Conducting Randomly Rough Surface

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Tsinghua Science and Technology 2002年第3期7卷 309-316页

作者：刘宁李宗谦 State Key Laboratory on Microwave and Digital Communications Department of Electronic Engineering Tsinghua University Beijing 100084 China

A scattering model is developed to predict the scattering coefficient of a conducting randomly rough surface by analyzing the randomly rough surface in the spectral domain using the bi-spectrum method. For common randomly rough surfaces without obvious two-scale characteristics, a scale-compression filter can divide the auto-correlation spectrum into two parts with different correlation lengths. The Kirchhoff approximation and the small perturbation method are used to obtain the surface field, then a bistatic scattering model, the bi-spectrum model (BSM), is used to derive an explicit expression from the surface field. Examples using the integral equation model (IEM), finite difference of the time domain (FDTD) method, and BSM show that the BSM accuracy is acceptable and its range of validity is similar to IEM. BSM can also be extended to a scattering model for dielectric randomly rough surfaces.

关键词： microwave remote sensing conducting randomly rough surface scattering model spectral domain bi-spectrum scattering model

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Physical model of acoustic forward scattering by cylindrical shell and its experimental validation

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Chinese Physics B 2010年第5期19卷 369-377页

作者：雷波杨坤德马远良 College of Marine Northwestern Polytechnical University

Research on the underwater target scattering can provide important theoretical support for target detection. The scattering model of cylindrical shell is established in this paper. It is found that the forward target strength is much stronger and varies with angles of incident wave less significantly than backward target strength. The received forward signal strength fluctuates with the target moving due to the interference between direct signal and scattering signal, which is most significant when the target approaches the baseline. An experiment is carried out in an anechoic tank to validate the scattering model. The method of acquisiting forward scattering in the tank is proposed. The forward and the backward target strengths are achieved by using the pulse compression technology, and they axe about 3dB less than the modeling results. The forward scattering phenomena of quiescent and moving targets are measured, which are similar to modeling results with different target types.

关键词： scattering model forward scattering target strength shell

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Adaptive polarimetric decomposition using incoherent ground scattering models without reflection symmetry assumption

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Geo-Spatial Information Science 2015年第1期18卷 1-10页

作者： Xiaoguang CHENG Wenli HUANG Jianya GONG Nanjing Research Institute of Electronics Engineering 99 Houbiaoying RoadNanjing 210007China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan University129 Luoyu RoadWuhan 430079China Department of Geographical Sciences University of MarylandCollege ParkMD 20742USA

Most of the current incoherent polarimetric decompositions employ coherent models to describe ground scattering;however,this cannot truly reflect the fact especially in natural ground *** paper proposes a highly adaptive decomposition with incoherent ground scattering models(ADIGSM).In ADIGSM,Neumann’s adaptive model is employed to describe volume scattering,and to explain cross-polarized power in remainder matrix,so that we can obtain orientation angle randomness for both volume scattering and the dominant ground *** computation of volume scattering parameters is strictly constrained for non-negative eigenvalues,while the volume scattering parameters that explain the most cross-polarized power are *** applying ADIGSM to NASA’s UAVSAR data,the negative component powers were obtained in quite a few forest *** with several newest decompositions,the volume scattering power is obviously lowered,especially in areas dominated by surface scattering or double bounce *** orientation angle randomness of each component is reasonable as *** has potential to be applied in the fields such as PolSAR image classification,land cover mapping,speckle filtering,soil moisture and roughness estimation,etc.

关键词： polarimetric synthetic aperture radar(PolSAR) polarimetric decomposition non-negative eigenvalue decomposition(NNED) scattering model

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Review of Ultraviolet Non-Line-of-Sight Communication

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China Communications 2016年第6期13卷 63-75页

作者： Renzhi Yuan Jianshe Ma Shenzhen Graduate School of Tsinghua University Shenzhen 518055China

With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.

关键词： ultraviolet communication non-line-of-sight scattering model

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Hole mobility of strained Si/(001)Si_(1-x)Ge_x

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 48-54页

作者： WANG XiaoYan ZHANG HeMing MA JianLi WANG GuanYu QU JiangTao Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices School ofMicroelectronics Xidian University Xi＇an 710071 China Department of Electron and Electricity Engineering Baoji University of Arts and Sciences Baoji 721007 China

The hole mobility of strained silicon along the orientation on (001) Si1?xGex is obtained by solving collision term in the Boltzmann transport equation. The analytical model is proposed that considers the effect of strain-induced splitting at valence band valleys in silicon, doping dependence and three scattering mechanisms, i.e., ionized impurity scattering, acoustic phonon scattering and non-polar optical phonon scattering. The hole occupancy at top band indicates a non-monotonic variation under biaxial tensile strain at low temperature (77 K). What's more, a non-monotonic variation of hole mobility at room temperature (300 K) is presented. Compared with the room temperature hole mobility, the low temperature hole mobility is affected greatly by ionized impurity scattering at lower impurity concentration. At the same time, the room temperature hole mobility is lower than that of electron with the same germanium content and doping concentration. If the parameters are correctly chosen, the model can also be used to calculate the hole mobility of other crystal faces with arbitrary orientation. So, it lays a useful foundation for strained silicon devices and circuits.

关键词： subband hole occupancy scattering model germanium content hole mobility

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Sea Roughness Trend Measurement using Power Waveforms of GPS Direct and Reflected Signals

Sea Roughness Trend Measurement using Power Waveforms of GPS...

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第37届中国控制会议

作者： Mohammad Shohidul Islam Dongkai Yang S M Injamamul Haque Masum Sultana Easmin Siddika Rodolfo D.Moreno Santillan School of Electronic and Information Engineering Beihang University School of Economics and Management Beihang University International School Beihang University

Sea roughness trend measurement is important to understand the present and future sea state conditions. It can be considered as an advance process of sea surface bulletin and sea weather forecasting. In this research, sea surface roughness trend is measured according to the nature of power waveforms of GPS direct and reflected signals. Remote sensing technique is proposed to generate power waveforms of GPS direct and reflected signals. This technique has been utilizing as an effective technique to understand ＆ determine the sea state monitoring, especially for sea wind estimation, sea wave height measurement, sea roughness measurement and so on. The power waveforms are generated by Z-V scattering model. Mainly, two models are used to perform the whole process. At first, wave spectrum model is used to find sea surface slopes（up ＆ cross variance） and then scattering model is used to generate power waveforms using the up and cross variance. Sea surface roughness trend is determined using the features of the amplitudes of these waveforms. From the analysis, it is obtained that features of power waveforms are sharply different for different ocean surface weather conditions, which means that there is a relationship between amplitude of the waveforms and sea surface weather conditions. This relation is used to measure the sea roughness conditions. The results of this paper are found good performance compared to sea surface wind. The results of this research have also provided the preliminary idea about the sea surface and in future, the idea can help to measure the others ocean parameters.

关键词： GPS direct & reflected signals power waveforms scattering model sea roughness trend

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Sea Wind Speed Estimation from Power Waveforms of GNSS-R Delay Signals of Beidou MEO Satellite

Sea Wind Speed Estimation from Power Waveforms of GNSS-R Del...

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第37届中国控制会议

作者： Mohammad Shohidul Islam Dongkai Yang Sultana Easmin Siddika Rodolfo D.Moreno Santillan S M Injamamul Haque Masum School of Electronic and Information Engineering Beihang University School of Economics and Management Beihang University International School Beihang University

This paper focuses the characteristics of power waveforms according to different wind speed of sea surface and then sea wind speed is estimated from the amplitude of power waveforms. The power waveforms are generated from the delay signals of Beidou MEO satellite. The remote sensing of GNSS concept is utilized to get information from sea surface. Because, this technique has been already proved as an effective tool to retrieve significant information from earth’s surface since last twenty years. Still now, it has been utilizing as an advance technique for sea state monitoring, i.e. sea wind speed ＆ direction, sea wave height, sea roughness measurement and so on. It is mainly generated the waveforms of Beidou MEO satellite for direct and reflected signals. It is obtained that the amplitude ＆ shape of these power waveforms are varying according to wind speed. It is indicated that there is a sharp relationship between the amplitude of the waveforms and sea wind speeds. Two models are used to generate the waveforms from reflected signals. The wave spectrum model is used to find sea surface slopes i.e. up ＆ cross variance and these up ＆ cross variance is used as input on Z-V scattering model to generate power waveforms. The real wind speed of the experiment site of GNSS-R data collection for same time domain is also collected. The linear regression method is used to established a relationship between wind speeds and amplitudes of the waveforms. This relation is used to measure the sea wind speed. It is found that estimated wind speeds are matched closely with real wind speed and model waveforms performs good results with real data waveforms.

关键词： Power waveforms reflected signals scattering model wave spectrum model wind speed

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