多源遥感图像融合发展现状与未来展望

近年来,随着遥感技术的发展,高光谱、红外、雷达等多源遥感成像手段在精准农业、资源调查、环境监测、军事国防等重要领域发挥着越来越重要的作用.同一场景多源遥感图像观测的地物对象相同,但观测的维度不同,图像的空间、光谱与时间分辨率存在差异,提供的信息既具有冗余性,又具有互补性和合作性.多源遥感图像融合能够综合利用不同来源获取...     

遥感技术在我国水电建设前期工作中的应用

80年代以来,我国先后在雅砻江二滩、长江三峡、红水河龙滩、黄河龙羊峡、金沙江溪落渡、白鹤滩等地开展了大规模的水电站建设前期遥感调查。采用多种类、多时相、多平台遥感资料的综合解译,并辅以一定量现场验证的工作方法,进行了区域地质背景、库岸稳定性、库岸土地利用、淹没损失、库区环境等项调查,为电站可行性论证提供了更加全面和科学的资料。我国水电遥感工作的特点是：规模宏大、内容广泛、方法合理、协同攻关。随着遥感技术的进步及水电事业的发展,我国水电遥感应用存在的问题也日益突出,有待于研究解决,遥感应用水平也待不断提高。     

北斗坐标系

北斗坐标系是北斗卫星导航系统的大地基准.本文在扼要叙述背景情况之后,首先给出了北斗坐标系原点、尺度、定向的定义和参考椭球的定义和导出常数;其次介绍北斗坐标系的首次实现,这次实现由北斗系统的8个监测站在历元2010.0的ITRF2014框架下的坐标和速度体现,它们是通过处理一个包括8个监测站的全球GNSS网4期GPS数据、框架对准与监测站坐标序列的线性回归拟合得到的;最后就参考框架的更新周期、监测站境外布设和连续观测、精密星历的生成与发布,北斗坐标系的标准化问题进行了讨论,并提出一些建议.     

通导遥一体化深远海PNT基准及服务网络构想

从海底控制网设计、布设、测量、数据处理和海洋声速场构建几个方面介绍了海底控制网建设的现状。结合国家海洋战略需求和海洋大地测量技术发展,分析了现阶段海底控制网建设面临的问题:认为目前的海底网规模小,缺乏信息共享,功能单一;设计与布设原则未与控制网等级关联,多为定性描述,缺乏操作性;声速场精度和分辨率偏低;测量和数据处理仅考虑了海底控制点的定位问题,难以满足大区域、高精度海洋PNT（positioning, navigation, and timing）基准网建设需求。据此,利用海洋声道的远程通讯和测距定位能力,提出了建设联合北斗/GNSS（global navigation satellite system）定位和通信导航功能的通导遥一体化深远海PNT基准及服务网络的构想,针对该网络的功能和布放设计、高精度、高分辨率海洋声速场模型的构建、各类PNT基准点的测量和整体网平差处理、海底PNT基准点的自校准和自维护、覆盖水域的位置增强服务、目标和环境的遥测和感知服务等几个关键技术问题,提出了实施方法和设想,以期解决当前海洋控制网大区域建设面临的缺乏通讯、布网原则和测量方法不完善、功能单一等问题,为新一代高性能海洋大地测量及PNT导航定位服务网络的建设提供支撑。认为随着长距离布网优化设计、增强位置服务、精确授时和时间同步、远程通讯及网络功能的拓展和应用服务等难题的突破,所构想的网络体系必将引起海洋PNT建设的一次变革。     

SURVEY FOR COLONIAL DEVELOPMENT

Abstract

The Inaugural General Meeting of the newly-formed Land Surveying Division of the Royal Institution of Chartered Surveyors was held at the Headquarters of the Institution in London on Wednesday, 14th December, 1949, when the following paper was read by Brigadier M. Hotine, C.M.G., C.B.E., F.R.I.C.S., Director of Colonial Surveys. This meeting, which is the precursor of others that are to be held in future at regular intervals, is of particular importance to surveyors since it was the first occasion on which those of them who had joined the Institution recently, but. werenot members oj any of the Committees appointed in connection with theformation of the Land Surveying Division, had been able to meet together as a separate Division of the I nstitu.tion, and thus to take their part in one of the Institution's normal activities. Brigadier Hotine's paper, together with an account of the Proceedings of the meeting, was published in the January issue of the Journal of the Institution and readers who belong to the Institution will thus already have had an opportunity of reading it. A large number of our readers, however, do not belong to the Institution, and do not see the Journal, and hence, and especially considering the special importance of the occasion and the intrinsic interest to all land surveyors of the subject with which the paper dealt, we have obtained the kind permission of the Editor to reproduce from the Journal the text of the paper and of the discussion which preceded and followed it.     

应用“3S”技术进行北京市森林立地分类和立地质量评价的研究

本文针对目的森林立地分类和立地质量评价研究中存在的问题。试图从立地分类和评价的方法进行技术上新的探讨。研究中以生态学和景观生态学理论为基础,以遥感（ＲＳ）、地理信息系统（ＧＩＳ）和专家系统（ＥＳ）作为主要的技术手段,借助相关数学分析,对北京市森林进行立地类型划分和在此基础上的立地质量评价及多目标动态决策。通过对北京地区景观特征及其气候、地貌、地形、土壤、植被等各种因子的定性分析,以及一、二类调查数据的定性定量分析,结合实际应用,确定分类原则和分类系统。应用ＧＩＳ建立各级分类的各因子专题数据库和图形库,通过各分类层次的主导因子及辅助因子的专题图叠加完成初分类。在此基础上,应用知识库中的专家知识及ＥＳ的推理机制对初分类结果进行综合,根据可信度理论,得出各级符合生产、造林规划和经营实际的立地类型图。对于最低一级的分类结果,采用专家打分的方法进行各类型立地质量的多因子综合评价,并编制立地质量评价图。在分类和评价的基础上,可以根据森林的生态效益、经济效益、环境效益和社会效益的综合考虑选择目标集,进行面向目标的动态决策。     

局部特征匹配的卫星影像几何偏差估计可行性分析

几何定位偏差是评估卫星影像质量的重要参数之一。本文利用特征匹配方法进行卫星影像几何偏差估计,并对该方法的可行性进行分析。首先,选取包含典型地物的局部卫星影像构建路标基准影像库;其次,采用局部点特征描述子对卫星影像与路标基准影像库进行亚像素提取与匹配,确定同名像点,然后为提升同名像点匹配精度,提出了顾及空间关系与几何一致性约束的匹配策略,继而,对卫星影像与路标基准影像库的匹配像点进行内插计算,获取同名像点的地理空间坐标;最后,通过差值计算得到卫星影像相对路标基准影像的偏移参数,完成几何偏差估计和可行性分析。本文以我国风云卫星为例,选取包含海岸线、湖泊、山脉、河流及岛屿的局部卫星影像集构建路标基准影像库,并选用SIFT、SURF、ORB 3个局部特征进行测试分析。测试结果表明,基于局部特征匹配策略对卫星影像几何偏差估计的系统误差小于0.1像素,定量地证明了局部特征匹配方法对卫星影像几何偏差估计的可行性。     

THE ECOLOGY OF RUSSIA ON MAPS

An overview paper, providing general information on research in the field of ecological mapping, surveys the cartographic study of ecological problems occurring in Russia at present and defines priority problems for the future development of this field. Among the criteria used to categorize the inventory of the ecological cartographic products of Russia are map topic, scale, time of compilation, format, and regional distribution. The survey was carried out under the auspices of the Russian Federation Ministry of Science, Higher and Intermediate Education, and Technical Policy at the Institute of Geography, Russian Academy of Sciences, in collaboration with specialists of many institutions and organizations of the country—The Siberian Section, Institute of Geography; the Russian State Library; and others. Translated by Edward Torrey, Alexandria, VA 22308 from: Izvestiya Akademii Nauk, seriya geograficheskaya, 1994, No. 1, pp. 107-118.     

应用遥感信息复合方法的森林分类和动态监测研究

在森林资源清查和动态监测中，一般要求能识别树种、在树种复杂时也要求识别到树种组。成图时要求可直接使用几何精度高、类型边界清晰的中比例尺如１：２．５万的影像图。为了满足生产的需要，我们进行了遥感信息复合、遥感与非遥感信息复合及复合方法等实用技术应用的研究。实验中应用了ＭＳＳ与ＴＭ卫星图像、ＴＭ不同时相的图像、ＴＭ与Ｓｐｏｔ的复合，及复合前后信息特征变化的定量分析等研究。从而为最优波段组合、特征信息提取方法提供了基础。在动态分析中主要进行了采伐迹地、林墙、迹地更新等方面的测定，并对测定精度进行了评估。     

旅游资源单体管理信息系统的设计与实现

旅游资源单体作为旅游资源普查的重要成果，具有数量多、分布广、资料丰富等特点。利用计算机对旅游资源单体普查成果资料进行集中管理，对旅游资源的统计、评价、分析与规划利用具有重要意义。文中介绍了旅游资源单体管理信息系统的系统需求分析、系统的体系结构、系统的数据库及功能设计，详细讨论了系统实现的关键技术，并总结了系统的特点。     

浅论中国亚热带遥感现状、任务与创新发展途径

中国亚热带区域覆盖范围广,面积达240万km²。区内不仅自然景观复杂,多云多雨、多山多林,生物多样性丰富、是中国稻米主产区,而且多河多湖、多矿多污,生态环境十分敏感、自然灾害多发频发,迫切需要利用遥感技术监测其自然资源、环境变化与灾害现象。虽然近年来国内外已逐渐开展亚热带遥感应用研究,但缺乏对亚热带遥感理论与方法的系统性研究,共性与科学问题尚不明晰。本文总结分析了中国亚热带遥感的3个基本特征,按遥感数据类型梳理了中国亚热带遥感的应用实践;进而归纳出中国亚热带遥感实践的4个共性问题,指出亚热带遥感核心元素的主要特点、地理对象的复杂性与遥感信息的病态性,提出中国亚热带遥感的4项重点任务;然后,分析了当今中国亚热带遥感发展的历史机遇,阐述了中国亚热带遥感的创新发展途径,包括厘清人地现象的动态特征、聚焦亚热带遥感的科学问题、攻克不同层面的关键难题、结合应用需求开展技术攻关与重点研发。论文旨在推动亚热带遥感应用的创新发展、促进亚热带遥感理论与技术体系形成,进而助力卫星及航空遥感更好地服务于中国亚热带地区的资源环境监测、区域防灾减灾、生态文明建设与“双碳”目标。     

GIS-based morphometric analysis of five major sub-watersheds of Song River,Dehradun District,Uttarakhand with special reference to landslide incidences

Evaluation of the morphometric parameters requires preparation of drainage map, contour map, ordering of the various streams and measurements of catchment area, perimeter, relative relief, relief ratio, length of drainage channels, drainage density, drainage frequency, bifurcation ratio, texture ratio, circulatory ratio and constant channel maintenance, which help to understand the nature of the drainage basin. The present study involves the Geographic Information System (GIS) analysis techniques to evaluate and compare linear, relief and aerial morphometry of the five subwatersheds of Song River (tributary of the Ganga River) with special reference to landslide incidences, for future development and planning of the watershed. Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi are the five major subwatersheds of the Song River basin. All the subwatersheds are basically of 5^th to 6^th order. Drainage patterns are mainly dendritic to sub dendritic. The drainage pattern of the Song River basin is mainly structurally controlled and the area is characterized by high to moderate relief. The asymmetric factor indicates that the tectonic rotation of the four subwatersheds is upward on the right side of the drainage basin and only one sub-watershed is downward. The numbers of the landslide incidences are also more in the upward side, than the downward side of the Song River basin.     

Forward modeling of GPS multipath for near-surface reflectometry and positioning applications

Multipath is detrimental for both GPS positioning and timing applications. However, the benefits of GPS multipath for reflectometry have become increasingly clear for soil moisture, snow depth, and vegetation growth monitoring. Most multipath forward models focus on the code modulation, adopting arbitrary values for the reflection power, phase, and delay, or they calculate the reflection delay based on a given geometry and keep reflection power empirically defined. Here, a fully polarimetric forward model is presented, accounting for right- and left-handed circularly polarized components of the GPS broadcast signal and of the antenna and surface responses as well. Starting from the fundamental direct and reflected voltages, we have defined the interferometric and error voltages, which are of more interest in reflectometry and positioning applications. We examined the effect of varying coherence on signal-to-noise ratio, carrier phase, and code pseudorange observables. The main features of the forward model are subsequently illustrated as they relate to the broadcast signal, reflector height, random surface roughness, surface material, antenna pattern, and antenna orientation. We demonstrated how the antenna orientation—upright, tipped, or upside-down—involves a number of trade-offs regarding the neglect of the antenna gain pattern, the minimization of CDMA self-interference, and the maximization of the number of satellites visible. The forward model was also used to understand the multipath signature in GPS positioning applications. For example, we have shown how geodetic GPS antennas offer little impediment for the intake of near-grazing reflections off natural surfaces, in contrast to off metal, because of the lack of diversity with respect to the direct signal—small interferometric delay and Doppler, same sense of polarization, and similar direction of arrival.     

流域尺度景观生态耗水研究

笔者将景观生态学、遥感蒸散计算技术等应用于流域生态耗水研究,先利用1980年、1990年、2000年、2005年的4期遥感数据,研究流域土地利用演变特征,并对流域景观生态进行分区。然后利用MOD IS数据和平流干旱模型,计算2005年生长期蒸散分布;再结合流域水资源评价成果,计算景观生态消耗的水资源、不可控水资源和可控水资源;最后又结合规划目标,对白杨河流域生态保护系统2020年与2030年生态需水进行了预测。通过研究,弄清了流域景观生态对象、功能、格局和过程、弄清了其消耗的水资源类型、数量和时空分布,为优化配置水资源、实现流域可持续发展开辟了新途径。     

An alternative approach to calculate the posterior probability of GNSS integer ambiguity resolution

When precise positioning is carried out via GNSS carrier phases, it is important to make use of the property that every ambiguity should be an integer. With the known float solution, any integer vector, which has the same degree of freedom as the ambiguity vector, is the ambiguity vector in probability. For both integer aperture estimation and integer equivariant estimation, it is of great significance to know the posterior probabilities. However, to calculate the posterior probability, we have to face the thorny problem that the equation involves an infinite number of integer vectors. In this paper, using the float solution of ambiguity and its variance matrix, a new approach to rapidly and accurately calculate the posterior probability is proposed. The proposed approach consists of four steps. First, the ambiguity vector is transformed via decorrelation. Second, the range of the adopted integer of every component is directly obtained via formulas, and a finite number of integer vectors are obtained via combination. Third, using the integer vectors, the principal value of posterior probability and the correction factor are worked out. Finally, the posterior probability of every integer vector and its error upper bound can be obtained. In the paper, the detailed process to calculate the posterior probability and the derivations of the formulas are presented. The theory and numerical examples indicate that the proposed approach has the advantages of small amount of computations, high calculation accuracy and strong adaptability.     

Evaluation of NTCM-BC and a proposed modification for single-frequency positioning

Ionospheric delay is a dominant factor that affects the accuracy of single-frequency positioning. Thus, an empirical ionospheric model with high accuracy is very important for single-frequency users. This study proposes a modified empirical broadcast ionospheric model, called MNTCM-BC, based on the Neustrelitz Total Electron Content (TEC) broadcast model NTCM-BC. Nine daily ionospheric coefficients of these models are estimated using datasets of the previous day from 30 globally distributed Global Navigation Satellite System monitor stations, and the prediction performance of the MNTCM-BC is evaluated with the datasets of the current day from all 300 verification stations. The results show that the complex behavior of the ionosphere is well described by the MNTCM-BC, including the visibility of two ionization crests on both sides of the geomagnetic equator and the TEC variations that depend on the local time and geomagnetic latitude. In terms of the prediction accuracy, compared with the NTCM-BC, the main improvement in the MNTCM-BC is achieved in summer, whereas the accuracy is comparable in other seasons. Hence, the following analyses are focused on summer. In the low-solar activity year of 2009, the prediction accuracy of the MNTCM-BC is improved by 0.11 TECU compared with that of the NTCM-BC. As to the high-solar activity year of 2014, the corresponding improvement is 0.35 TECU. In addition, when the number of monitor stations is increased from 30 to 300, the prediction accuracy of two models can be slightly improved by 0.06 TECU in 2009 and 0.13 TECU in 2014, respectively, while reliability enhances. Furthermore, the average three-dimensional positioning accuracy of 160 globally distributed stations for single-frequency point positioning using the Klobuchar model, the NTCM-BC and the MNTCM-BC is 1.83, 1.21 and 1.20 m during quiet day and 3.15, 2.31 and 2.21 m during perturbed day, respectively. Relative to the Klobuchar model and the NTCM-BC, the average accuracy improvements in the MNTCM-BC are about 30 and 3%, respectively.     

CONNECTION OF INDIA,SIAM AND MALAYA TRIANGULATIONS

Abstract

In an article in the Review of October 1938, iv, 30,450-457, under the heading “Geographical Positions in Malaya and Siam”, Mr. A. G. Bazley gives a comparison of the Indian and Siamese, and Siamese and Malaya, triangulations at common points and discusses the possibility of an error in the longitude of the datum of the Malayan system. In the Review of April, 1939, v, 32, 112-113, he has elaborated certain points, and remarks in connection with the doubt in the longitude of the Malayan datum that connection of the F.M.S. network with that of Siam and India, and some more latitude and longitude observations by the F.M.S. Survey, are essential to a satisfactory solution of this rather involved problem. Since the above article was written, a lot more infornlation has become available about the Indo-Siamese triangulation connections and a firm connection between the triangulations of Sianl and Malaya has been established in 1946. It is hoped that a review of the present position would be of interest, especially as the various links effected open up a definite possibility of a continuous chain of triangulation from India to Australia.     

数据驱动的定量遥感研究进展与挑战

定量遥感是从原始遥感观测信息中定量推算或反演出地学参量的理论与方法.传统定量遥感主要基于模型驱动,强调通过数学或物理模型完成推算和反演.随着人工智能技术的发展和普及,数据驱动的方式也逐渐受到广泛关注,其强调的是通过机器学习等方式挖掘遥感观测数据中所包含的信息,完成地学参量的定量反演.在强大计算能力的支持下,数据驱动的方...     

THE GEODIMETER: AN INSTRUMENT FOR THE ACCURATE MEASUREMENT OF DISTANCES BY HIGH-FREQUENCY LIGHT VARIATIONS

Abstract

During the last few years a method of measuring accurately the lengths of lines of moderate length by means of high-frequency variations in the intensity of light emitted by a special transmitter, which promises to have many important applications in triangulation and precise traversing, has been devised by Mr. E. Bergstrand, of the Geographical Survey of Sweden. In principle, the method has certain resemblances to the apparatus invented and used by Fizeau for measuring the velocity of light, Bergstrand's instrument having been designed in the first place for the measurement of the same constant. In Fizeau's apparatus, it will be remembered, a ray of light was directed through the cogs of a revolving toothed wheel towards a distant mirror, and, when the wheel reached a certain angular velocity, the ray reflected from the mirror was intercepted by the cogs, so that an observer stationed on the same side of the wheel as the light source no longer saw the reflection of the light in the mirror. The angular velocity of the wheel being known or observed, the time taken for the cogs to obliterate the reflected image could be calculated, and twice the distance to the mirror divided by this time gave the velocity of light. In the Bergstrand apparatus, which is called the “geodimeter”, light pulses of known frequency and varying intensity are directed to the end station of the line whose distance is required, and, after reflection by a mirror at that station, are received back in a special receiving apparatus alongside the transmitter. Here they are converted into small electric currents, which, when the required distance is a certain function of the wave length of the transmitted and reflected pulses, can be made to give zero deflection on a sensitive galvanometer. In this way, the distance to be measured can be determined in terms of the wave length of the pulses. Experiments so far carried out with this apparatus have been successful up to distances of about 36 kilometres. Even with the latest model, however, as we shall see later, it is necessary to know the approximate distance to within 1½ km.     

煤炭开采对泥河小流域土地利用及景观格局的影响

以淮南煤矿区泥河小流域1987、1994、2000、2006、2009、2013、2017年7期多源遥感影像为数据源,结合纹理和光谱特征,利用支持向量机（SVM）对遥感影像进行分类,在此基础上分析了煤炭开采对泥河小流域近30年土地利用和景观格局变化的影响。结果表明：煤炭开采影响下流域的土地利用变化最显著的特征是耕地和建设用地的相互转变及耕地向塌陷水体的转变,30年间塌陷水体和建设用地分别增加了2 281.05、14 741.73 hm²,耕地减少了15 044.67 hm²。采煤驱动下,流域景观格局变化特征体现在以2006年为转折点,前期呈现破碎化、不规则化、异质化和低连通性变化的特征,之后呈现连续化、规则化、均衡化及高连通性变化的特征。建设用地、耕地和塌陷水体经历了不断破碎化到景观逐渐完善的过程;耕地、建设用地和自然水体斑块形状较为复杂;耕地优势性逐渐减弱,最大斑块指数由79.706 0降为38.745 5,塌陷水体和建设用地的优势性增强。