国际新闻

对地成像卫星概况指南美国摄影测量与遥感学会(ASPRS)发布了“对地成像卫星概况指南”(Guide to Land I maging Satellites)。指南总结了对地成像卫星的现状,汇集了大于等于39米的在轨卫星和2010年前已计划发射的卫星资料。由于技术进步,造一颗中高分辨率的卫星只要1000-2000万美元,从而使空间对地成像无所不在。目前巳有13个国家拥有中高分辨率的卫星在运行。而到2010年会达到20个国家。经统计,所有民用对地成像卫星,分辨率为39m或者更高,到2010年前在轨的光学成像卫星将有30颗,计划发射的有25颗。在轨雷达卫星有4颗,计划发射的为8颗。…     

“一带一路”区域国产中高分辨率宽波段多光谱卫星数据获取技术研究

大区域数据快速拍摄获取是遥感卫星任务规划领域的重要研究课题,依托“国产中高分辨率宽波段多光谱卫星数据集构建和高效国际化服务”项目,使用吉林一号光谱01/02星开展了对“一带一路”沿线65个国家和地区三年两期的有效覆盖。总结了项目大区域数据获取的策略方法和经验,重点介绍了数据获取相关的星地资源等各类影响因素、大区域按时相划分策略、以及基于云量预报有效成像条带的大区域动态规划流程,即在卫星单次过境范围内,结合云图选取最大概率获取有效数据的成像条带。该研究已为项目提供常态化支持,相关方法和项目经验可为一般卫星遥感大范围、广区域数据获取任务提供参考借鉴。     

应用前景广阔的高分辨率遥感卫星QuickBird(快鸟)影像数据

Quick Bird高分辨率遥感卫星是由美国 Digital Globe /Earth Watch公司于 2 0 0 1年 1 0月 1 8日发射成功的目前全世界最高分辨率的商用遥感卫星。 Quick Bird遥感卫星影像在空间分辨率 ( 0 .61 m)、多光谱成像( 1个全色通道、4个多光谱通道 )、成像幅宽 ( 1 6.5 km X1 6.5 km)、成像摆角 ( 0 - 2 5°)等方面具有显著的优势 ,能够满足更专业、更广泛应用领域的遥感应用需求 ,能提供更好、更快的遥感信息源服务。Quick Bird影像产品分基本影像、标准影像、正射影像、立体像对等不同类型 ,从波段组成上影像产品分全色波段影像数据、多光…     

高分辨率IKONOS卫星影像及其产品的特性

自从 1994年 3月 10日美国克林顿政府颁布关于商业遥感数据销售新政策以来 ,解禁了过去不准 10～ 1m级分辨率图像商业销售 ,使得高分辨率卫星遥感成像系统迅速发展起来。就美国而言 ,有 5～ 6家公司致力于 1～ 5 m的卫星遥感成像系统研制 ,其中美国空间成像公司 (Space Imaging)的 IKONOS卫星是最早获得许可之一。经过 5年的努力 ,于 1999年 9月2 4日空间成像公司率先将 IKONOS- 2高分辨率 (全色 1m,多光谱 4m)卫星 ,由加州瓦登伯格空军基地发射升空。1　IKONOS卫星的基本特性IKONOS卫星是由加州的洛克希德—马丁建造的。它具有…     

“全球生态系统碳循环关键参数立体观测与反演”项目概述与研究进展

准确评估全球碳循环是准确估算未来大气CO₂浓度、预测气候变化的关键。目前全球陆地与海洋碳源汇估算时空不确定性大。除碳循环模式理论和认知存在缺陷外,全球尺度上缺乏精细时空分辨率的生态系统碳循环参数观测数据是造成全球碳循环估算存在巨大不确定性的重要原因之一。为此,项目以立体观测为技术手段,通过协同全球台站观测资料和多源卫星遥感数据,研制要素齐全的高质量陆地与海洋生态系统碳循环关键参数产品（GLOCC）,不仅包括主要碳源汇直接观测产品,如陆地生态系统生产力、生物量、土壤碳库和海水二氧化碳分压、海水颗粒有机碳等;还包括陆地与海洋生态系统光合作用关键参数以及碳循环模型过程关键变量。项目执行3 a多来,收集与处理了1981~2019年来的28种国内外卫星数据和19种全球碳循环产品生产相关的全球遥感产品,攻克了多源卫星遥感数据的一致性处理关键技术,发展了陆地与海洋生态系统碳循环关键参数的高精度卫星反演关键技术,初步研制了GLOCC碳参数产品生产与共享平台,并通过集成国内外卫星遥感数据,将部分陆地生态系统碳参数的时间分辨率从8 d提高到5 d。目前已经有7个GLOCC产品在国内外多个数据中心提供了产品共享服务。项目预期能够为全球变化研究提供时空分辨率高、时间序列长、碳循环参数全的遥感产品,并服务于全球碳源汇准确估算需求,并提供全球和区域碳收支的重要科学数据。     

我国对地观测卫星应用成就与展望

本文回顾了我国对地观测卫星在地面数据处理系统建设及卫星数据应用方面取得的成就,并对我国未来对地观测卫星及地面系统发展进行了展望,包括建设国家陆地观测卫星数据中心、建设国家高分辨率对地观测数据中心以及实现我国对地观测连续化、卫星运行业务化、数据获取方式多样化等。     

日本先进的陆地观测卫星(ALOS)

1　 1　 ALOS概要日本的地球观测卫星计划由两组系列组成 :一组用于大气和海洋观测 ,另一组主要承担陆地观测。先进的陆地观测卫星 (Advanced Land ObservingSatellite— ALOS)是继日本地球资源 1号卫星 (JER-S- 1 )和先进的地球观测卫星 (ADEOS)之后研制的卫星。ALOS增强了陆地观测技术 ,将用于制图、区域观测、灾害监测和资源调查。ALOS安装了 3个遥感仪器 :用于数字高程制图的立体成像全色遥感仪 (PRISM)、能准确地观测土地覆盖的高性能可见近红外辐射计 (AVNIR- 2 )、适合于全天时全天候观测的相阵型 L-波段合成孔径雷…     

高分辨率卫星成像系统的发展简介

高分辨率卫星成像系统的发展简介魏晨曦（洛阳跟踪与通信技术研究所）前言高分辨率卫星遥感图像在测绘，制图、建筑、城市规划、资源管理、环境监测、新闻报道、地理信息服务以及军事侦察和军备控制协议核查等方面均具有广泛的用途。１９９５年以后，随着一些新的商业遥感...     

国内新闻

“北京一号小卫星”正式运行发布会在北京举行2006年6月8日,“北京一号小卫星”正式运行发布会在北京举行。这颗高性能对地观测小卫星是根据国家“十五”科技攻关计划和高技术研究发展计划(863计划)的安排,由科技部、北京市、国土资源部、国家测绘局和二十一世纪空间技术应用股份有限公司共同支持的。“北京一号小卫星”是一颗具有中高分辨率双遥感器的对地观测小卫星,卫星重量166.4kg、轨道高度686km、中分辨率遥感器为32m多光谱,幅宽600km,高分辨率遥感器为4m全色,幅宽24km,卫星具有侧摆功能,在轨寿命5年(推进系统7年)。卫星研制周期仅2年…     

不同分辨率对遥感影像中识别人造地物的影响

高分辨率卫星影像的出现为提取特定目标的空间结构信息提供了物质基础,通过分析一组不同分辨率的同一地区的模拟遥感影像,讨论了不同分辨率对遥感影像中识别人造地物的影响,并从定性定量两个方面解释了影响产生的原因,为从遥感影像中识别特定地物提供了参考分辨率,同时也为以识别人造地物为目标的遥感图像分割提供了有益的探索。     

基于Petri网和混合蚁群算法的多星成像调度

提出一种基于综合指标Petri网和混合蚁群算法的多星成像调度策略。在综合指标Petri网变迁中引入指标信息,处理多星并发观测和卫星资源竞争关系、反映卫星能量和存储等约束,使得问题描述更直观和完备。设计一种嵌入局部搜索技术的蚁群优化算法,通过启发式信息综合变迁中的指标,引导蚂蚁进行全局搜索。仿真实例结果表明,该策略能有效求解多星成像调度问题,实现全局搜索和快速收敛的平衡。     

Object-based land cover change detection for cross-sensor images

Accurate and timely land cover change detection at regional and global scales is necessary for both natural resource management and global environmental change studies. Satellite remote sensing has been widely used in land cover change detection over the past three decades. The variety of satellites which have been launched for Earth Observation (EO) and the large volume of remotely sensed data archives acquired by different sensors provide a unique opportunity for land cover change detection. This article introduces an object-based land cover change detection approach for cross-sensor images. First, two images acquired by different sensors were stacked together and principal component analysis (PCA) was applied to the stacked data. Second, based on the Eigen values of the PCA transformation, six principal bands were selected for further image segmentation. Finally, a land cover change detection classification scheme was designed based on the land cover change patterns in the study area. An image–object classification was implemented to generate a land cover change map. The experiment was carried out using images acquired by Landsat 5 TM and IRS-P6 LISS3 over Daqing, China. The overall accuracy and kappa coefficient of the change map were 83.42% and 0.82, respectively. The results indicate that this is a promising approach to produce land cover change maps using cross-sensor images.     

Terrestrial remote sensing science and algorithms planned for EOS/MODIS

The Moderate Resolution Imaging Spectroradiometer (MODIS) will be the primary daily global monitoring sensor on the NASA Earth Observing System (EOS) satellites, scheduled for launch on the EOS-AM platform in June 1998 and the EOS-PM platform in December 2000. MODIS is a 36 channel radiometer covering 0·415-14·235 μm wavelengths, with spatial resolution from 250 m to 1 km at nadir. MODIS will be the primary EOS sensor for providing data on terrestrial biospheric dynamics and process activity. This paper presents the suite of global land products currently planned for EOSDIS implementation, to be developed by the authors of this paper, the MODIS land team (MODLAND). These include spectral albedo, land cover, spectral vegetation indices, snow and ice cover, surface temperature and fire, and a number of biophysical variables that will allow computation of global carbon cycles, hydrologic balances and biogeochemistry of critical greenhouse gases. Additionally, the regular global coverage of these variables will allow accurate surface change detection, a fundamental determinant of global change.     

Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems

The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations.The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modern repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored.     

A global land-cover validation data set,part I: fundamental design principles

A number of land-cover products, both global and regional, have been produced and more are forthcoming. Assessing their accuracy would be greatly facilitated by a global validation database of reference sites that allows for comparative assessments of uncertainty for multiple land-cover data sets. We propose a stratified random sampling design for collecting reference data. Because the global validation database is intended to be applicable to a variety of land-cover products, the stratification should be implemented independently of any specific map to facilitate general utility of the data. The stratification implemented is based on the Köppen climate/vegetation classification and population density. A map of the Köppen classification was manually edited and intersected by two layers of population density and a land water mask. A total of 21 strata were defined and an initial global sample of 500 reference sites was selected, with each site being a 5?×?5 km block. The decision of how to allocate the sample size to strata was informed by examining the distribution of the sample area of land cover for two global products resulting from different sample size allocations to the 21 strata. The initial global sample of 500 sites selected from the Köppen-based stratification indicates that these strata can be used effectively to distribute sample sites among rarer land-cover classes of the two global maps examined, although the strata were not constructed using these maps. This is the first article of two, with the second paper presenting details of how the sampling design can be readily augmented to increase the sample size in targeted strata for the purpose of increasing the sample sizes for rare classes of a particular map being evaluated.     

Dependence of frequency of convective cloud occurrence on the orbital drift of satellites

Deriving accurate time‐series of cloud cover from satellite sensor data still remains a challenging task. The instruments onboard polar orbiting NOAA satellites offer the opportunity to prepare cloud climatology on a global scale; however, the orbital drifts of these satellites can introduce uncertainty when deriving such cloud climatology. The aim of this letter is to point out the importance and to estimate the impact of orbital drift on long‐term time‐series of the observation of convective cloud frequency of occurrence. The 20 years of daytime AVHRR data from over the Indian subcontinent for the summer monsoon season is used in this study. All four AVHRRs onboard NOAA‐7, ‐9, ‐11, and ‐14 satellites show positive correlation between increased cloud frequency and the delay in equator crossing‐times during their lifetime. This increase is significant over land, but over the ocean, there is no discernible effect. This effect should be considered to avoid spurious trends in cloud cover. Further in‐depth investigations are needed to make possible corrections.     

Artificial neural networks paddy-field classifier using spatiotemporal remote sensing data

Monitoring changes in a paddy-field area is important since rice is a staple food and paddy agriculture is a major cropping system in Asia. For monitoring changes in land surface, various applications using different satellites have been researched in the field of remote sensing. However, monitoring a paddy-field area with remote sensing is difficult owing to the temporal changes in the land surface, and the differences in the spatiotemporal characteristics in countries and regions. In this article, we used an artificial neural network to classify paddy-field areas using moderate resolution sensor data that includes spatiotemporal information. Our aim is to automatically generate a paddy-field classifier in order to create localized classifiers for each country and region.     

An overview of small satellites in remote sensing*

This article gives a global overview of some aspects of small satellite developments since the launch of Sputnik‐1 50 years ago. These developments are offering new opportunities for remote sensing.

The earliest satellites were small but, as time went on, the satellites that were flown were developed to serve several different projects and they became larger and more expensive and took a long time to design, build and be launched. One of the extreme examples was Envisat. For these large satellites compromises often had to be made between different objectives and different instruments. A failure of the whole system meant the death of many different projects.

The future is likely to see more small satellites, each of which is dedicated to a particular mission objective and carries a single instrument. Through this approach more and more countries around the world are becoming involved in Earth observation from space, not just in using the data from the major established systems but also in constructing their own systems.

There were some small, low‐cost satellites in the early days, but they were overlooked or considered toys by the space community. The first microsatellites were built by enthusiasts of the amateur radio community and launched in the early 1960s. The invention/introduction of the microprocessor in the 1970s represented a quantum jump for the onboard capabilities of a spacecraft. This technology introduction represented a prime catalyst in the development of microsatellites since it enabled small physical structures in support of sophisticated data handling applications. The engineering of microsatellites, which emerged in the early 1980s, took a radical change of approach from the custom design of traditional spacecraft, namely a design‐to‐capability scheme to achieve cost reductions by focusing on available, and existing technologies using a general purpose bus and ‘off‐the‐shelf’ components and instruments.

The new approach of small satellite design was pioneered by Surrey Satellite Technology Ltd (SSTL) of Surrey University, UK. SSTL's lead has now been followed by various companies and space agencies throughout the world. A key feature of this work is the development of microsatellite technology transfer programmes, providing partnerships and on‐the‐job training of engineers and scientists of foreign national organizations in cooperative programmes – in particular to those who were not in a position to start or afford their own space projects – to participate in the development of their own microsatellites.

In addition to discussing these developments, this article also covers small satellite classification, small satellite initiatives in the USA, small satellite development in the rest of the world, some aspects of the technology and applications of small satellites, and small satellites developed by universities, particularly the CubeSats programme.

Today, small satellites are changing the economics of space. These spacecraft embrace cutting edge Commercial Off‐The‐Shelf (COTS) technology, permitting novel and less‐expensive ways to perform meaningful observation missions, although there are various technical challenges. There are several synthetic aperture radar (SAR) and hyperspectral imaging missions on small satellites in operation and in planning.     

AVHRR data sets for determination of desert spatial extent

A programme of global arid and semi-arid land monitoring is currently underway at NASA/Goddard Space Flight Center using meteorological satellite data to detect possible climatic change as manifested by changes in arid and semi-arid land extent. This has resulted in the processing and interpretation of a large amount of satellite data from the NOAA-series of polar-orbiting satellites. Techniques are described and preliminary results presented for determination of the boundary between the Sahara Desert and the Sahel Zone of Africa using daily advanced very high resolution radiometer data from 1980–1992. Some of the techniques may be of interest to other researchers who are or will be using large multi-year data sets derived from coarse-resolution satellite data to investigate large-scale land surface questions.     

卫星成像规划调度系统中的可视化决策支持研究与实现

本文提出了一种成像卫星规划与调度的可视化决策支持方法。该方法基于多目标进化算法和地理信息系统技术，能够在考虑多目标准则、多约束的条件下对成像卫星的成像方案进行优化，并通过可视化技术进行成像方案的决策辅助，很好地解决了卫星规划调度优化方案制定的问题。