用拟准检定法探测和修复GPS数据中的粗差和周跳

用粗差的拟准检定法来探测和修复GPS相位观测中的粗差和周跳，概述了用拟准检定法探测和修复周跳的数学模型，并给出了具体实施步骤，用两个算例验证本文方法的可行性和有效性。     

基于拟准检定法的多波束测深粗差探测

针对最小二乘趋势面滤波法在多波束测深粗差探测中存在的不足,本文提出将拟准检定法应用于多波束粗差探测中,进而将拟准检定法探测粗差与最小二乘趋势面拟合有机结合起来。通过构造不同阶次的趋势面,并对实测数据进行分析,结果表明:拟准检定法剔除粗差后海底地形表面较为平滑,微小地形得以保存,跳点和孤立点得以剔除。     

粗差拟准检定的实施方案设计

拟准检定法是根据真误差与观测值有确定的关系式RΔ=-RL,通过直接解算真误差估值Δ来检测粗差。由于真误差能直接反映粗差的大小，所以这种方法可靠性强。本文主要阐述该方法的实施方案设计思想及其步骤和选择“拟准观测”的一些技巧。     

拟准检定法及其在测量中的应用初探

经典最小二乘平差假定观测数据中不含有粗差,但随着现代测绘技术发展,数据采集的自动化程度越来越高,对数据采集过程进行人工干预较难实现,观测结果包含粗差在所难免。本文探讨利用拟准检定法进行粗差探测的原理、特点及优势,并通过模拟算例,验证了拟准检定法处理粗差的有效性。     

估计观测值粗差三种方法的等价性讨论

在粗差定位一致的前提下,证明了拟准检定法与部分最小二乘法的粗差估值具有等价性;LEGE法粗差估值与部分最小二乘法粗差估值具有等价性,其条件为未受污染观测值等权独立,且与受污染观测值相互独立.仿真算例证明,当未受粗差污染观测值不等权时,拟准检定法与部分最小二乘法得到的粗差估值结果相同,均比LEGE法粗差估值结果更准确、精度更高.     

一种卫星钟差异常精确探测的两步法策略

针对卫星钟差数据中的粗差和钟跳两类异常进行精确探测,提出使用历元单差算法和拟准检定法相结合的两步法策略,第1步,依据钟跳和粗差在历元单差序列中不同表现特点,采用历元单差法探测疑似钟跳点并剔除部分粗差;第2步,对按疑似钟跳分段的数据使用拟准检定法精确探测粗差。通过模拟数据算例阐述钟差异常探测过程并进行性能分析,通过实测数据进行算法有效性验证,结果表明,仅使用历元单差法能有效探测疑似钟跳点和部分粗差,其探测的疑似钟跳点包含了真实钟跳;使用两步法既能有效规避钟跳影响,又能精确探测小粗差,探测能力接近底噪的2倍中误差。     

用拟准检定法和补偿最小二乘估计解算污染半参数模型

现代自动化测绘技术采集的测量数据中系统误差和粗差都在所难免,需要同时考虑系统误差和粗差共存的平差问题.针对污染半参数模型中含有系统误差和观测值受到污染而不严格服从正态分布的情形,文章探讨了用拟准检定法抵御粗差,用补偿最小二乘法分离系统误差.算例表明:用拟准检定法对粗差进行定位定值并对观测误差进行修正后,再利用补偿最小二乘法解算半参数模型,可以得到较好的结果.     

论真误差拟准解的基本特性

本文将回答这样一个问题：为什么拟准检定法能准确地定位粗差并估计出粗差大小？首先从理论上论证真误差的估值的重要特性：真误差拟准解的大小完全由它对应的观测值中的粗差决定,因此它能直接反映粗差的位置和大小。本文还用算例验证了这一结论。     

粗差的拟准检定法(QUAD法)

以往对付粗差的各种方法都是以余差（残差）为研究对象的。本文提出一种全新的研究思路和方法,从真误差入手。真误差与观测值有确定的解析关系。但关系式的系数阵是秩亏的。本文借鉴周江文的“拟稳平差”思想,提出“拟准观测”的概念,附加“拟准观测的真误差范数极小”的条件,解决了关于真误差的秩亏方程组求解定解的问题,推导了粗差的拟准检定法算式。该方法依据真误差估值的分布特征,检测粗差准确可靠。不仅能有效地同时定位     

三种粗差检测方法的比较及分析

通过对数据探测法、拟准检定法和多维粗差同时定位定值法进行比较研究,对算例进行数值分析,比较这三种方法的优缺点。     

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。     

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...     

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.     

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.     

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。     

“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。