船载岛礁综合测量系统多传感器时间同步

时间同步是多传感器协同工作的基础,船载岛礁综合测量系统中的激光扫描仪系统和多波束测深系统需要与G PS 实现时间同步,针对激光扫描仪本身不具有时间同步功能,提出一种G PS脉冲与网络通信相结合的时间同步方法,方法实现简单并且同步误差较小。实验证明：利用所提出的方法多传感器信息可取得良好的融合效果。     

建筑物立面激光点云的定位

车载式近景目标3维测量系统,采用激光扫描仪获取建筑物立面点云.激光点云仅具有扫描仪坐标系下的坐标,不便于其他数据融合进行3维建模.文中根据系统的特点和要求,通过建立相应的坐标系,利用已有或优化的坐标转换模型确定坐标系之间的坐标转换关系.依据基准点与载体平台GPS接收机之间同步观测数据将激光点云在扫描仪坐标系下的坐标经过多次坐标转换,得到基准点所在当地坐标系下的坐标.使系统实现了满足精度要求的建筑物立面激光点云的定位工作.     

建筑物立面激光点云的定位

车载式近景目标3维测量系统,采用激光扫描仪获取建筑物立面点云。激光点云仅具有扫描仪坐标系下的坐标,不便于其他数据融合进行3维建模。文中根据系统的特点和要求,通过建立相应的坐标系,利用已有或优化的坐标转换模型确定坐标系之间的坐标转换关系。依据基准点与载体平台GPS接收机之间同步观测数据将激光点云在扫描仪坐标系下的坐标经过多次坐标转换,得到基准点所在当地坐标系下的坐标。使系统实现了满足精度要求的建筑物立面激光点云的定位工作。     

3D激光扫描应用于开采沉陷相似材料模型观测

根据开采沉陷相似材料模型实验的特点,采用了三维激光扫描仪对开采沉陷相似材料模型进行观测,得到了测点的拟合与建模两种三维坐标数据,分析了模型的下沉曲线,实现了用三维激光扫描仪对开采沉陷相似材料模型观测新方法的研究.     

车载3D激光扫描系统集成技术

移动激光扫描技术是从上世纪90年代初逐步发展起来的一门测绘技术,也是当今测绘界最为前沿的技术之一,可用于工程测量和制图等诸多领域。地面3D激光扫描仪具有测量速度快,精度高等优点。本文以奥地利RIEGL公司的地面三维激光扫描仪VZ400为例,研究将其作为移动测量系统的主要传感器所涉及的关键技术,包括联机控制、时间基准统一和空间基准统一三个方面:解析了激光扫描仪的接口定义,并结合联机控制的开发库——RiVLIB实现的仪器的联机控与数据通信;给出了基于GPS秒脉冲信号的时间同步原理,实现了系统时间基准的传递与统一;分析了移动测量系统中的坐标系,并根据地面三维激光扫描仪的实际情况,构建了单站的参数标定模型。通过本文的研究与实验,使测量系统实现常见移动测量的二维帧扫描模式以及针对重点区域的三维全景扫描模式,同时,当它闲置时还可将激光扫描仪拆卸进行静态的扫描,丰富了系统的测量方式,提高了系统的适应性与使用效率。     

3维激光扫描仪的全站化实现方法

3维激光扫描仪扫描得到的是目标点的相对坐标,无法直接满足需要大地坐标的工程应用的要求,且不同扫描站间点云数据的拼接非常麻烦.对这些问题,让3维激光扫描仪如全站仪一样能够直接获得大地坐标是一种理想的解决办法.分析了3维激光扫描仪的工作原理,介绍了扫描仪的极坐标系和直角坐标系并推导了其转换关系;在扫描仪中引入旋转平台和平台坐标系,推导了平台坐标系与扫描坐标系及大地坐标系之间的转换模型.在此基础上将扫描坐标转化为大地坐标,实现3维激光扫描仪的全站化.     

车载GPS／IMU／LS激光成像系统外方位元素的动态标定

提出一种带有微小转角修正的车载激光成像系统外方位元素标定方法.针对全球定位系统(GPS)、惯性测量单元(IMU)和激光扫描仪(LS)集成的车载激光成像系统(车载移动测绘系统),该方法使用6个微小旋转角参数和6个微小平移参数对传统标定模型参数进行修正.试验数据表明,方法可对系统的安装误差和时间同步误差进行有效改正.     

地面激光扫描中激光强度值的影响因素及改正方法

激光强度作为地面三维激光扫描仪特有的测量值,在现有三维激光扫描仪中并没有得到有效利用.鉴于此,文章从理论上推导了激光强度值的影响因素,根据强度值的影响因素提出了一种强度值的改正方法,并通过实验对理论模型进行了验证分析.实验结果表明:本文提出的改正方法能较好地对强度值进行改正,对相关的硬件制造和应用具有一定的价值.     

车载激光扫描系统的三维数据获取及应用

通过对南水北调移民新村进行移动平推式扫描,将导航POS获取的系统位置和姿态信息与360°激光扫描仪获取的扫描距离和角度信息进行时间匹配,解算得到大地坐标下的三维激光点云坐标,然后与线阵CCD相机获取的图像信息进行彩色融合,最终得到移民新村的彩色点云数据,实现了实时、主动、完整地获取和处理南水北调移民新村的三维空间数据信息,取得了一定的效果。     

3维激光扫描仪的全站化实现方法

3维激光扫描仪扫描得到的是目标点的相对坐标,无法直接满足需要大地坐标的工程应用的要求,且不同扫描站间点云数据的拼接非常麻烦。对这些问题,让3维激光扫描仪如全站仪一样能够直接获得大地坐标是一种理想的解决办法。分析了3维激光扫描仪的工作原理,介绍了扫描仪的极坐标系和直角坐标系并推导了其转换关系;在扫描仪中引入旋转平台和平台坐标系,推导了平台坐标系与扫描坐标系及大地坐标系之间的转换模型。在此基础上将扫描坐标转化为大地坐标,实现3维激光扫描仪的全站化。     

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.     

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.     

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services

Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.     

GIS空间数据的采集误差及其分析

本文详细阐述了GIS数据采集过程中的误差来源，重点分析了通过地图、遥感和摄影测量等方式采集数据所产生的误差及其特性，分析了其对GIS数据的影响与消减方法。     

地理数据库的关系模型及其实现

本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。