高速铁路框架控制网数据处理中基线解算模式分析

BASELINE和RELAX是GAMIT软件基线处理中两种不同的解算模式,为对比两种基线处理模式在高速铁路框架控制网数据处理结果,并确定何种基线处理模式更适用于高速铁路框架控制网的数据处理,应用BASE-LINE、RELAX基线处理模式进行基线处理,并采用TGPPS软件进行网平差,以均方根误差、基线重复性、基线较差、网平差等结果进行对比.结果表明,高速铁路长大干线的框架控制网基线解算中采用BASELINE效果较好.     

网解和PPP解的等价性

证明了PPP解与网解的等价性,比较了网解和PPP解模式下的位置和对流层延迟参数的解算结果,实验验证了这两种GPS解算模式下参数解的等价性。     

CORS支持下的单点测量模式的探讨

针对传统GNSS控制网中需要多人多台设备同步观测的缺点,提出了利用CORS来进行单点测量的模式,并利用Bland-Altman对两种测量模式进行检验。采用CORS单点测量模式代替网模式,较好地解决了在网观测中多台设备同步观测的缺点,根据Bland-Altman检验,测量结果能达到E级网测量结果。基于CORS单点测量模式的实践表明,本文所提的测量模式不仅能满足区域控制网的要求,也能较好地提高高精度控制测量的效率,研究结果是对高精度控制测量方法的补充,可以应用于农村集体土地登记发证等项目中。     

基于精选基准消秩亏的GNSS参考网数据处理方法

全球导航卫星系统（GNSS）参考网多用于估计卫星轨道/钟差、监测地表形变和速度场、确定精密地球自转参数等方面。相关数据处理模式包括：双差基线解（DD）和非差精密单点定位（PPP）等。本文首先从GNSS基本观测方程出发,通过选取两组基准参数,导出了上述两模式下的列满秩观测方程,然后分析了它们的不足,例如：相位偏差在DD模式中吸收了钟差,丧失了时不变特性;模糊度在PPP模式中吸收了相位偏差,失去了整数性。基于上述分析,本文提出了一种新的参考网数据处理方案,以充分融合DD和PPP模式的优势。它的关键策略是精选基准参数,以达到消秩亏的目的,具体优点体现在：相位偏差独立可估,若合理约束为时不变参数,可充分减少参数个数,提高网解精度;待估模糊度具备整周特性,经由模糊度固定,可改善网解可靠性。     

专用工程GNSS控制网的建立与优化

综合利用精密单点定位和静态相对定位两种技术优化偏远地区专用工程控制网的建立模式,通过对实测GNSS数据,采用专用网优化方案与传统同步静态相对定位观测方法取得成果的分析和比较,证明优化后取得的成果在减少作业量、保证可靠性的同时,能满足专用工程控制网对位置和方位基准的精度要求。     

区域GPS大地测量新老作业方式的配合

建立区域ＧＰＳ网原来有两种模式：一是最初采用的野外会测模式；二是１９９０年出现的连续作业模式，即常设ＧＰＳ大阵测量阵列（ＰＧＧＡ）。最新发展的建网策略略是 两种模式配合起来，称为多模式设站策略（ＭＯＳＴ），它利用ＧＰＳ大地测量自８０年代中期以来发生的一些显著变化。近两年来，美国加州和中部各州以及南太平洋、中亚、地中海中部、智利和阿根廷都已经采用ＭＯＳＴ策略，它已经被认为是第三类ＧＰＳ大地测量策略。     

利用GPS城市控制网准动态模式拟合高程精度分析

利用GPS准动态模式采集数据基线处理后,引入到GPS城市控制网整体平差拟合高程,讨论采用多项式曲面拟合及平面拟合两种模型多种已知点分布状态对拟合高程精度的影响。     

基于优化理论的GPS网形设计模型研究

GPS变形监测网优化对于高精度工程测量的变形监测精度具有重要的影响,但是它与传统控制网的优化设计有所不同,因此在对GPS控制网进行优化设计时考虑的因素与传统控制网也不同.现将传统控制网中的精度、可靠性、灵敏度、费用指标引入到GPS网中进行优化设计,提出了两种基于冗余数的优化设计方法:一种是基于冗余数的GPS控制网的优化设计,另一种兼顾冗余数和精度的GPS控制网的优化设计方法,并通过河南省交通规划勘察设计院承办的云台山到武陟段高速公路GPS控制网的设计对两种方法进行了比较,验证了两种方法的可行性和有效性,证明了应用第二种方法进行GPS控制网的优化设计是较为科学的方法.此外,针对变形监测网的特点,将灵敏度指标引入到GPS变形监测网的设计中,深入研究了基于灵敏度的GPS变形监测网的优化设计,并通过实例验证了该方法的优化有效性和可行性.     

POS辅助机载三线阵影像自检校光束法平差

将基于附加参数的自检校光束法区域网平差技术用于机载三线阵CCD传感器ADS40影像的几何定位处理中,分析并建立POS数据的引入模型、两种模式的自检校附加参数模型以及自检校光束法区域网联合平差模型。采用试验场ADS40数据进行不同地面控制点配置的常规和自检校光束法区域网平差试验。结果表明,自检校光束法区域网平差能够有效补偿影像存在的系统误差,显著提高定位精度。     

关于国家重力一等网平差方案的一个注记

国家一等重力网(简称一等网)是国家1985年重力基本网(简称85网)的一级附合网。关于一等网的平差原则,大致有两种意见。第一种将85网点起始重力值作为固定值,将一等网强制符合在85网上。即85网固定;第二种将85网点重力值作为具有先验精度的虚拟观测值,联合新测绝对重力点值和仪器标定观测,从而提出联合平差方案。平差结果将使85网点起始值得到一定改正数,即85网不固定;上述两种意见的折中,是将85网重力基准作为一等网平差的拟稳基准。细析之,85网点值虽未作为观测值获得直接改正,但也不是固定值。     

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。