用间隔三差相位模型整体平差GPS网

本文提出用间隔三差相位模型处理ＧＰＳ观测数据，整体平差ＧＰＳ网。阐述了基本模型和数据处理方法。用以此模型和方法为基础编写的软件ＳＯＳＤＳ处理了１９９１年５月至１９９２年４月观测的分布在全国范围的５３个点的ＧＰＳ网数据。结果显示出，基线精度为２×１０－８；基线向量的单弧解算精度为４０ｃｍ（Ｎ）、９３ｃｍ（Ｅ）和１０６ｃｍ（Ｕ）；点位坐标的相对精度为３×１０〔－８〕。     

DGPS测量飞机的航7维状态参数

针对ＧＰＳ卫星ＳＡ和ＡＳ技术的人为精度降低措施，应用多个地面基准站的ＤＧＰＳ载波相位测量模式，精确地测得了飞机在航三维实时时点位、对地摄影地元和三维飞行速度；其二维点位的外部符合精度达到了±７．９ｃｍ，高程外部符合精度为±１８．１ｃｍ。     

青藏高原块体相对运动模型的GPS方法确定与分析

利用武汉测绘科技大学在１９９３年、１９９５年观测的两期ＧＰＳ资料,具体分析了青藏高原各块体相对运动情况。目前青藏高原大约以３３．４ｍｍ／ａ,Ｎ３０°Ｅ方向向西伯利亚运动,其中巴颜喀拉块体、羌塘块体、拉萨—冈底斯块体和喜马拉雅块体大约分别以１７．３ｍｍ／ａ±３．１ｍｍ／ａ,Ｎ３５°Ｅ;２５．７ｍｍ／ａ±５．１ｍｍ／ａ,Ｎ３３°Ｅ;３８．９ｍｍ／ａ±６．１ｍｍ／ａ,Ｎ２９°Ｅ;４６．０ｍｍ／ａ±６．２ｍｍ／ａ,Ｎ２７°Ｅ方向朝西伯利亚运动,而西藏块体大约以２８．５ｍｍ／ａ±５．０ｍｍ／ａ速率,Ｎ３１°Ｅ方向朝西伯利亚运动,这些结果与地质结果符合。文中还给出了各块体相对运动的欧拉向量。     

基于沿海业务观测的ＢＤＳ大气可降水量反演

随着中国北斗导航卫星系统新一代ＢＤＳ－３卫星发射,需要对ＢＤＳ反演大气可降水量的精度进行评估。选取 ４个中国沿海ＧＮＳＳ业务观测站,采用精密单点定位方法,设计了ＢＤＳ－２、ＢＤＳ－３和ＢＤＳ－２／３等３种数据处理方案, 开展岸基ＢＤＳ水汽反演试验,并以ＧＰＳ　ＰＷＶ和ＥＣＭＷＦ提供的ＥＲＡ５产品作为参考值,对ＢＤＳ　ＰＷＶ进行精度分 析。结果表明,利用新一代ＢＤＳ－３卫星反演的ＢＤＳ－３ＰＷＶ和ＢＤＳ－２／３ＰＷＶ与ＧＰＳ　ＰＷＶ和ＥＲＡ５ＰＷＶ参考值均 具有很好的一致性,其平均偏差分别为０．６ｍｍ和０．２ｍｍ,均方根误差分别优于１．０ｍｍ和１．６ｍｍ,具有较高的精 度,从而验证了新一代ＢＤＳ－３卫星对ＢＤＳ水汽反演精度提升的贡献;ＢＤＳ－２／３ＰＷＶ的精度略优于ＢＤＳ－３ＰＷＶ,在 一定程度上验证了ＢＤＳ混合星座对水汽反演精度的影响。     

EPOCH‘92全球GPS联测部分站资料的处理结果

ＩＧＳ在１９９２．６．２１～１９９２．９．２２组织了全球ＧＰＳ联测，在此期间的７．２６～８．８二周时间为加强观测，参加台站多达６００余个，用以研究ＧＰＳ的各个方面，取名为ＥＰＯＣＨ＇９２。本文对ＥＰＯＣＨ＇９２期间前后共１８天的全球分布的２４个站的资料进行了归算处理，得到的基线精度为５ｍｍ＋８．３５ｐｐｂ，定轨精度好于２ｍ，地球定向参数ｘｐ，ｙｐ解的精度约为１ｍａｓ。     

武汉基准台超导重力仪重力潮汐观测结果

本文采用重力残差信号对武汉基准台超导重力仪的原始观测数据（２０秒采样）作预处理，将原始观测信号分解成重力潮汐和残差两部分，在残差信号中消除一些已知的干扰因素的影响。利用ＥＴＥＲＮＡ软件作调和分析，两主波（Ｏ１和Ｍ２）的重力潮汐参数（振幅因子和相位滞后）为：Ｏ１：１．１７８８±０．０００６，－０．５９７５°±０．０２８°；Ｍ２：１．１７１３±０．０００２，－０．５８７３°±０．００８°经海潮改正以后，Ｏ１和Ｍ２波的潮汐参数与Ｗａｈｒ－Ｄｅｈａｎｔ潮汐模型值相比，振幅因子的偏差优于０．１％。     

GPS辅助光束法区域网平差—太原试验场GPS航摄飞行试验结果

本文简要介绍了ＧＰＳ辅助光束法区域网平差的基本原理和方法，详细讨论了太原航摄机动态试验场实际ＧＰＳ航摄飞行试验的结果。利用联合平差程序ＷｕＣＡＰＳ系统对试验区进行ＧＰＳ辅助光束法区域网平差，用分米级精度的ＧＰＳ摄站坐标获得了实地上平面为±７．９ｃｍ、高程为±１８．１ｃｍ的加密精度，充分显示了动态ＧＰＳ定位技术在航空遥感定位中的广阔应用前景。     

论我国米级精度大地水准面的实现

国家测绘局用ＧＰＳ水准技术布设全国高异常控制网，其中Ａ级网２７个点，Ｂ级网７６０个点，根据这些成果的初步计算，相对西安大地原点，我国东部和中部地区的高程异常控制网点的精度和分辨率有可能分别达到±０．７ｍ和１°量级，西部地区则相应±１．１ｍ和２．５°量级，因此我国具有米级精度的新一代似大地水准面是可能实现的。     

关于卫星测高中几个相关问题的讨论

一、引言７０年代发展起来的卫星测高技术和ＧＰＳ一样,是空间大地测量的一场革命。例如,运行时间只有三个月的Ｓｅａｓａｔ卫星,仅１６８４小时的测高结果就在纬度±７２°的范围内提供了分辨率为０．６°×０．６°,精度优于０．５ｍ的海洋大地水准面,使传统测量手...     

北斗三号短基线四频组合定位方法研究

摘　要：北斗三号全球卫星导航系统现已提供４个频率以上的观测数据,支持多频组合定位理论和方法的研究。基 于此,文中提出一种短基线下的北斗四频组合定位解算方法,利用北斗Ｂ１Ｉ,Ｂ３Ｉ,Ｂ１Ｃ,Ｂ２ａ４个频率的观测数据两两 组合形成独立不相关的窄巷观测值联立,以位置参数和双差模糊度组成状态向量,结合卡尔曼滤波估计进行定位解 算。基于该方法,文中针对两组不同长度的短基线进行测试,结果显示：在１７ｍ 短基线中,该方法平面精度优于 ２ｍｍ,高程方向精度优于４ｍｍ;在３ｋｍ的短基线中,平面精度优于４．５ｍｍ,高程精度优于６ｍｍ。测试结果表明, 在短基线情况下,该方法的定位精度相较于北斗单频及三频方法在平面和高程方向均有不同程度的提高。     

阿克苏河-塔里木河水系水质污染遥感监测与评价

 采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的 污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体 污染变化曲线,得出污染物浓度随着远离上游而增加。     

Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data

The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw.     

使用FME与VBA提取机场方格网高程数据

因受机场工程设计软件的测量数据容量限制,基于LiDAR采集、点云分类后得到的地面点云数据LAS不能完整应用于目前设计软件进行设计计算。本文通过对拟选技术方案的筛选,提出了利用FME Workbench数据处理功能,结合VBA编程获取外部方格网平面数据的方法。该方法在FME Workbench中实现了地面点云数据构建TIN、采用逐点内插方法从TIN中提取方格网高程数据、等高线生成及相应图形处理与成果输出。最终通过实际算例证明了该方法的有效性。     

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.     

Gravity Changes Before Large Earthquakes in China: 1998-2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200...     

GNSS系统及其技术的发展研究

阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议.     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。     

Virtual Australia: its key elements – know,think, communicate

Abstract

Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised.     

自动车辆定位导航系统中传感器的误差分析

对国界定位导航系统中几种常见的辅助传感器所产生的误差进行了分析，导出了不同传感器的误差模型。这些误差模型是估计车辆位置的扩展卡尔曼滤波器的基础，同时也为选择适当的传感器提供了理论根据。