无人机有效航片快速筛选算法研究

针对无人机航摄作业时,由于飞行姿态、航向、航速无法保持稳定,导致航片质量问题,文中通过分析相关影响因素,提出筛选航片的判断条件,研究设计快速提取有效航线、自动筛选有效航片的方法。该方法根据航片曝光点坐标信息,分析航线几何特征,运用曝光点方向角和航带长度的聚类算法,提取平行有效航带,自动筛选有效航片。经实际航摄任务验证,采用该方法,单架次的筛选耗时可由分钟级提升至秒级,结果准确率达到95%以上,显著提升筛选效率。     

航空遥感任务规划系统设计及航线设计方法研究

航空遥感任务规划系统服务于航空遥感飞行,航线设计是该系统中重要的功能之一。重点介绍所设计的航空遥感任务规划系统的框架结构、主要功能以及三种方法适用于不同设计环境下的航线设计方法,最后以贵州安顺的遥感飞行实例证明系统在航线设计方面所具备的能力。     

DEM航线曝光点坐标计算方法北大核心CSCD

提出一种基于全国DEM数据库,根据飞机飞行高度、飞行方向、设计重叠度、当前曝光点坐标,自动快速计算下一曝光点坐标的计算方法,该方法不但能满足直升飞机自由飞行路线的影像获取,而且能顾及地形起伏对像片重叠度的影响。试验表明,该方法设计的曝光点坐标更加科学、合理。     

DEM航线曝光点坐标计算方法

由于直升飞机需要第一时间内获取地震、泥石流灾区高分辨率航空影像数据,因此本文提出一种基于全国DEM数据库,根据飞机飞行高度、飞行方向、设计重叠度、当前曝光点坐标自动快速计算下一曝光点坐标的计算方法。该方法不但能满足直升飞机自由飞行路线的影像获取,而且能顾及地形起伏对像片重叠度的影响。实验表明,该方法设计的曝光点坐标更加科学、更加合理。     

利用DEM的自适应航线设计方法

由于直升飞机需要在第一时间内获取地震、泥石流灾区高分辨率航空影像数据,因此文章提出了一种新的实时相机曝光点设计方案,它可以根据DEM数据、飞行高度、飞行方向、设计重叠度实时自动根据当前曝光点坐标计算下一曝光点的坐标.该方法不但能实现直升飞机自由飞行路线的影像获取,而且能顾及地形起伏对像片重叠度的影响.通过实验表明,该方法设计的曝光点坐标更加科学、更加合理.     

考虑地球扁率的RNAV航路规划

考虑地球扁率的影响,在地理坐标系下推算区域导航(RNAV)航路点的经纬度坐标以及各航段的初始真航线角(TC)与航线距离,为机载区域导航设备提供更为精确的航迹指引和更为快捷的直飞航线。以IAG-75椭球参数为计算依据,根据空间向量分析,导出了RNAV大椭圆圈航线的初始TC、航线距离以及基于中间插值的航路点纬度计算方法。经计算,从B215航路的阜康至大王庄,现行等角航线距离为2642km,简化大圆航线模型的航线距离为2423.8km,而考虑地球扁率影响的大椭圆航线模型的航线距离为2435.3km。     

轻小型机载LiDAR的航线设计

为研究轻小型机载LiDAR的航线设计,以VUX-1型激光扫描仪为例,计算多周期回波(multi time around,MTA)对飞机作业高度的限制;根据要求的点云密度、扫描频率、扫描线速度等指标,依照航空摄影测量原理以及机载LiDAR数据获取规范,从中区别机载LiDAR与传统摄影测量学的不同,并借鉴机载LiDAR的数据采集方式与传统挂载专业相机的摄影测量的相似之处,判定在不同情形下激光的测距变化(例如测区内不同类型的目标反射率不同或大气能见度不同导致的最远测距能力的变化等);在考虑以上问题基础上,对机载LiDAR系统进行航线设计;最后分别对比旁向点间距和航向点间距的误差,分析其原因并判定该航线设计方案的可行性。     

3维可视化航摄规划系统的设计与实现

目前,国内的航线设计工作仍停留在传统的手工作业阶段,工作量大、生产效率低、设计费用较高.针对航摄工作的需求,中文在可视化仿真算法研究的基础上,设计并初步实现了一个3维可视化航摄任务规划系统,并利用模拟数据对系统进行了测试.测试结果表明,本系统能大大提高航线规划和设计工作的自动化程度,对航空摄影工作具有较强的辅助作用.     

基于DEM的机载LiDAR航线设计

本文参照我国航空摄影标准中有关相机的部分,深入研究了基于DEM的机载LiDAR航线设计中的关键技术,并研发出了LiDAR航线设计系统.试验表明,与传统航线设计方式相比,基于DEM的航线设计方式能够设计出更为准确、合理的航线.     

3维可视化航摄规划系统的设计与实现

目前，国内的航线设计工作仍停留在传统的手工作业阶段，工作量大、生产效率低、设计费用较高。针对航摄工作的需求，中文在可视化仿真算法研究的基础上，设计并初步实现了一个3维可视化航摄任务规划系统，并利用模拟数据对系统进行了测试。测试结果表明，本系统能大大提高航线规划和设计工作的自动化程度，对航空摄影工作具有较强的辅助作用。     

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。