一种基于道路监控视频图像质量评估的新方法

针对近些年图像质量评价的重要性,提出一种针对道路监控视频的图像质量评估方法。因为道路监控视频具有连贯性、图像稳定性强、单个监控视频场景单一等特点,本文采用一种结合多幅图像创建物理模型对比恢复天气影响的图像质量评估方法,通过多幅图像比较恢复道路视频图像清晰度,加入噪声亮度比的因子来增加图像的鲁棒性和准确性,分析该方法的优势和不足。     

A GIS‐based Vehicle Mobility Estimator for Operational Contexts

A vehicle mobility estimator has been developed to produce decision aid maps for projecting civil or military forces on operational theatres. Based on the exploitation of classical geographical sources (e.g. digital elevation models, optical images, and vector databases) and thematic sources (e.g. climate, meteorological, pedological and land cover databases), the system computes speed maps for different kinds of vehicles moving both on‐road and off‐road. Such computations are realized through a ground‐vehicle interaction module that estimates the vehicle performance from experimental results, numerical simulations and empirical relationships. The system's architecture is built using a GIS interface that manages the data, the computation and the presentation layers. An operational version of this tool has been tested and validated on several operational theatres in France and in northern Africa. The results show good agreement between the predicted mobility performance of various vehicles and those observed on the field. A case study is presented to illustrate the mobility maps and demonstrate their relevance in the decision‐making chain depending on different climate contexts. A short application to itinerary optimization is presented as a promising future application.     

带有差分GPS的多传感器无人直升机航测遥感系统

本文主要介绍作者在日本研制的一种基于无人直升机平台的多种传感器航测遥感系统,它直接采用GPS和IMU数据进行地理定位定向而不需要地面控制点。通过实飞数据对系统达到的几何精度进行了验证,结果表明该系统可用来测绘大比例尺地形图以及应用于其他相关领域。     

Road Reduction Filtering for GPS-GIS Navigation

A novel method of map matching using the Global Positioning System (GPS) has been developed for civilian use, which uses digital mapping data to infer the systematic position errors of less than 100m which result largely from 'selective availability' (S/A) imposed by the US military. Selective availability was switched off on the 2nd of May 2000, and is to be replaced with 'regional denial capabilities in lieu of global degradation'. The system tracks a vehicle on all possible roads (road centre-lines) in a computed error region, then uses a method of rapidly detecting inappropriate road centre-lines from the set of all those possible. This is called the Road Reduction Filter (RRF) algorithm. Point positioning is computed using C/A code pseudorange measurements direct from a GPS receiver. The least squares estimation is performed in the software developed for the experiment described in this paper. Virtual differential GPS (VDGPS) corrections are computed and used from a vehicle's previous positions, thus providing an autonomous alternative to DGPS for in-car navigation and fleet management. Height aiding is used to augment the solution and reduce the number of satellites required for a position solution. Ordnance Survey (OS) digital map data was used for the experiment, i.e. OSCAR 1 m resolution road centre-line geometry and Land Form PANORAMA 1:50,000, 50 m-grid digital terrain model (DTM). Testing of the algorithm is reported and results are analysed. Vehicle positions provided by RRF are compared with the 'true' position determined using high precision (cm) GPS carrier phase techniques. It is shown that height aiding using a DTM and the RRF significantly improve the accuracy of position provided by inexpensive single frequency GPS receivers.     

GPS/DR/MM组合导航中的车辆定位精度研究

本文介绍了GPS/DR/MM的工作模式和地图匹配的原则和方法,探讨了将车辆位置匹配到路段上的两种方法,即利用地图数据库或GPS点直接向路段投影。本文从理论角度提出提高车辆路段定位精度的方法,并利用公式进行了推导证明。推导结果表明,利用上述两种方法对车辆位置进行最佳估计,所获得的车辆位置的不确定性大大降低,为组合导航提供了理论依据。     

车载GPS道路信息采集和更新系统研究

介绍了车载道路信息采集和更新系统 (CRICUS)的设计和研究进展。该系统利用 3S集成技术采集道路信息并生成数字道路网数据库。初步实验表明 ,该系统的定位精度可达 1m。     

适合于AR应用的姿态、位置综合测量系统

本文分析了AR技术的发展需求,提出适合于AR智能导航的姿态、位置综合测量系统.该系统由双频GPS接收机、陀螺仪和车辆里程计组合,采用卡尔曼滤波方法实现位置姿态测量.文章估计了滤波器实时为动态AR智能导航系统输出的位置姿态信息的精度.并通过实验验证了系统的可靠性、适用性和稳定性.     

GPS软件接收机跟踪通道信号统计分析

传统的基于硬件的接收机由于芯片的封装性很难用来进行通道信号的分析研究,而基于软件无线电技术的软件接收机则很容易做到。软件接收机的跟踪通道信号统计分析可用于接收机算法的测试与比对以及卫星信号性能的分析与评估。这里搭建了GPS软件接收机L1中频数字信号处理平台,对跟踪通道输出的I、Q支路信号进行了均值、标准方差以及均方根(RMS)统计。分析了各统计值与通道对应卫星的高度角、信号强度以及噪声之间的关系。基于统计结果提出了一种估计信道信噪比的方法。最后比较了不同信号采样频率对相关三角形和导航定位解算精度的影响。     

GPS车辆导航中的实时地图匹配算法

通过误差来源的分析和误差模型的建立，提出了一种车辆导航中GPS定位测量与数字地图实时配准的地图匹配算法，这使得在现有的基本硬件配置条件下，车辆导航定位精度更高。最后对算法进行了分析，并给出了统计结果。     

A general map matching algorithm for transport telematics applications

This paper describes a map-matching algorithm designed to support the navigational functions of a real-time vehicle performance and emissions monitoring system currently under development, and other transport telematics applications. The algorithm is used together with the outputs of an extended Kalman filter formulation for the integration of GPS and dead reckoning data, and a spatial digital database of the road network, to provide continuous, accurate and reliable vehicle location on a given road segment. This is irrespective of the constraints of the operational environment, thus alleviating outage and accuracy problems associated with the use of stand-alone location sensors. The map-matching algorithm has been tested using real field data and has been found to be superior to existing algorithms, particularly in how it performs at road intersections.     

计算转换参数提高手持式GPS接收机定位精度的方法与探讨

通过在矿区施测的静态GPS控制测量,根据实际不同的坐标系工程用图需要,在矿区内均匀选择三个以上公共点的两套坐标,探讨对手持式GPS接收机求取其转换参数的方法,采用五参数转换法,求出转换参数,然后在手持GPS接受机上设置五参数来提高定位精度.     

移动激光测量系统应用于带状DLG生产的精度和效率研究

为测试移动激光测量系统应用于带状DLG生产的精度和效率,以某山区公路为试验区域,按照GPS信号强弱选择3个典型区域布设靶标。通过对比靶标的点云量算坐标与RTK实测坐标,统计分析移动测量测图精度,并总结带状DLG试生产效率。     

GVG农情采样系统及其应用

介绍了通过对GPS、VIDEO摄像头、GIS的综合集成 ,用于野外农作物采样的信息快速采集、定位和处理分析系统 ,简称为GVG农情采样系统。系统包括影像采集卡、视频摄像头、GPS接收卡、GPS天线和工控计算机 ,在野外采集时采用汽车为主要工作平台 ,以各级公路为样线进行动态采样。系统工作时实时采集GPS信号 ,捕捉视频影像 ,同时根据GPS位置自动获得GIS属性信息 ,并自动记录在后台数据库。野外工作结束后 ,系统提供的功能允许操作人员对每条记录的照片中各类农作物所占比例进行赋值 ,统计单元内各种作物的分类成数 ,包括采样线、县级、农业区划级和省级单元。GVG系统的自动数据采集方式和GIS支持下的图像分析和统计方法提高了数据的采集和室内数据分析的效率 ,同时保证了采样的精度 ,经过不同地区的精度检验 ,作为“中国农情遥感监测系统”的重要组成部分 ,在全国范围内对大宗农作物分类成数的监测精度达到 95 %以上。     

车载移动测图系统外方位元素标定方法

全景相机因其360°大视场、旋转不变性等优点,逐渐被用于构建车载移动测图系统。标定是保证系统获取精确地理信息数据的重要前提。本文针对全景相机和定位定姿系统(POS)集成的车载移动测图系统,提出一种外方位元素标定的方法。首先,在实际场景中布设高精度已知控制点。其次,构建全景球面模型,将全景影像通过球面投影反变换投影到该球面上,从球面上选择控制点而不是直接从存在扭曲的全景影像上选择控制点并得到其球面坐标。在建立点的相关性之后,结合地理参考绝对定位方程和坐标变换,求得全景相机相对POS的平移与旋转参数。最后,采用本文提出的标定方法,分别选择北京航天城和天津滨海新区进行试验。试验表明,GPS信号良好时,点的绝对定位中误差可达平面10.3cm、高程16.5cm;GPS信号不好时,点的绝对定位中误差为平面35.4cm、高程54.8cm;在较短距离范围内(3km),距离量测相对误差最大为5cm左右,GPS信号对相对量测没有明显影响。     

A Technology Fusion Approach for Augmented Reality Applications

Technology fusion through the integration of multiple sensors and data sources is a common feature of current spatial information applications. Augmented reality is one such example. Augmented reality is a technology that overlays views of the real world with digital information. It provides an innovative application of spatial databases and can be applied in both real‐time and non‐real‐time applications. In order to correctly align digital (augmented) data with views of the real world, position and attitude determination is required. This paper describes the development of an augmented reality prototype, which includes the design and implementation of a position and attitude determination component. The prototype relies on spatial information to improve the accuracy of position and attitude determination. Successful field tests of the prototype are carried out in Melbourne, Australia. The field tests are focused around a case study that uses the prototype to enable drivers to ‘see’ the road and surrounding vehicles despite heavy fog, rain, snow or other low visibility situations.     

GPS在卫星影像控制测量中的应用

随着遥感卫星影像分辨率的不断提高,利用卫星遥感影像进行地形图更新和测绘逐步成为一种高效率的测绘手段。利用GPS测量技术对卫星影像进行控制测量则是其中一项重要的基础工作。主要从GPS全野外控制测量作业方法、作业中的精度控制与分析及应注意的问题三个方面,就GPS测量技术在卫星影像控制测量中的应用作一介绍。     

HD-STGPS超站仪的实时坐标转换

HD－STGPS的特点是将GPS技术与TPS技术通过软件和掌上机（或便携机）及组合硬件有机结合在一起，利用GPS方法实时求得TPS的测站空间直角坐标，再通过适合的数学模型转换为地方坐标系的二维直角和正常高，这样可以实现即测即用的测绘模式。     

A Chain-Code-Based Map Matching Algorithm for Wheelchair Navigation

Accurate vehicle tracking is essential for navigation systems to function correctly. Unfortunately, GPS data is still plagued with errors that frequently produce inaccurate trajectories. Research in map matching algorithms focuses on how to efficiently match GPS tracking data to the underlying road network. This article presents an innovative map matching algorithm that considers the trajectory of the data rather than merely the current position as in the typical map matching case. Instead of computing the precise angle which is traditionally used, a discrete eight-direction chain code, to represent a trend of movement, is used. Coupled with distance information, map matching decisions are made by comparing the differences between trajectories representing the road segments and GPS tracking data chain-codes. Moreover, to contrast the performance of the chain-code algorithm, two evaluation strategies, linear and non-linear, are analyzed. The presented chain-code map matching algorithm was evaluated for wheelchair navigation using university campus sidewalk data. The evaluation results indicate that the algorithm is efficient in terms of accuracy and computational time.     

出租车GPS轨迹集聚和精细化路网提取

针对利用GPS数据提取双向路网和交叉路口转向信息精度低的不足,本文提出一种顾及位置与行驶方向的轨迹集聚和精细化路网提取方法,实现了精细化路网提取。为提高交叉路口路网的提取精度,首先剔除原始轨迹中的离散和异常轨迹点,并按一定的步长对轨迹段进行加密;然后引入行驶方向角来表达车辆在轨迹点处的行驶方向,顾及位置和行驶方向获取每个轨迹点的相似轨迹点集合;接着依次计算每个轨迹点的偏移距离,通过对轨迹点的迭代偏移完成轨迹集聚;最后剔除未成功集聚的轨迹点,将完成集聚的轨迹点连成轨迹线并作缓冲区,运用栅格数据数字化方法提取得到能够反映道路精细转向关系的道路网。以福州市出租车GPS数据进行轨迹集聚和路网提取试验,结果表明:本文方法能有效地将GPS轨迹按车辆行驶方向分别进行集聚,提取的道路网为双向道路并且能反映交叉路口处道路的精细转向关系。     

GIS applications for military operations in coastal zones

In order to successfully support current and future US military operations in coastal zones, geospatial information must be rapidly integrated and analyzed to meet ongoing force structure evolution and new mission directives. Coastal zones in a military-operational environment are complex regions that include sea, land and air features that demand high-volume databases of extreme detail within relatively narrow geographic corridors. Static products in the form of analog maps at varying scales traditionally have been used by military commanders and their operational planners. The rapidly changing battlefield of 21st Century warfare, however, demands dynamic mapping solutions. Commercial geographic information system (GIS) software for military-specific applications is now being developed and employed with digital databases to provide customized digital maps of variable scale, content and symbolization tailored to unique demands of military units. Research conducted by the Center for Remote Sensing and Mapping Science at the University of Georgia demonstrated the utility of GIS-based analysis and digital map creation when developing large-scale (1:10,000) products from littoral warfare databases. The methodology employed–selection of data sources (including high resolution commercial images and Lidar), establishment of analysis/modeling parameters, conduct of vehicle mobility analysis, development of models and generation of products (such as a continuous sea–land DEM and geo-visualization of changing shorelines with tidal levels)–is discussed. Based on observations and identified needs from the National Geospatial-Intelligence Agency, formerly the National Imagery and Mapping Agency, and the Department of Defense, prototype GIS models for military operations in sea, land and air environments were created from multiple data sets of a study area at US Marine Corps Base Camp Lejeune, North Carolina. Results of these models, along with methodologies for developing large-scale littoral warfare databases, aid the National Geospatial-Intelligence Agency in meeting littoral warfare analysis, modeling and map generation requirements for US military organizations.