移动增强现实在纸质地图中的应用

纸质地图曾是人类进行空间认知的重要工具。随着信息时代的科技发展,电子地图、网络地图等地图产品迅速崛起,而纸质地图存在较多固有缺陷,如一经出版便无法再更改、实时性差、信息量有限、呈现方式静态、缺乏动态效果和交互性等,因此受到较大冲击。移动增强现实技术给纸质地图的多样化表达提供了新的方向,有着广阔的应用前景。本文在对移动增强现实关键技术进行分析的基础上,通过实验开发了一个基于纸质地图的移动增强现实系统,将视频、三维地形模型等数字媒体与纸质地图相结合,实现了纸质地图的增强表达。     

Map Design Evaluation for Mobile Display

How to effectively represent spatial information on handheld mobile devices is a key question, given the increasing use of personal digital assistants (PDAs) and cell phones concurrent with the development of location-based services. The mobile use of digital maps on small displays presents new capabilities and challenges that differ from using paper maps in a mobile setting or viewing digital maps on a desktop computer. This research addresses these issues through a study that evaluated maps on a mobile device used for a field-based navigation task. Map representations at two levels of generalization were compared by analyzing subject performance in a pedestrian route-following task, in which a handheld computer was used as a navigation aid. Subject time and accuracy as well as interaction with the mobile device during the task were measured. The results carry implications for map design for small, mobile displays and identify factors that affect the use of maps while moving. Maps are and will increasingly be used on small displays in mobile contexts for a variety of purposes and in many different environments. The requirements and preferences of mobile users, as well as how these maps are used in different contexts, must be understood in order to inform more effective designs.     

面向ArGIS的多传感器混合跟踪注册研究

针对传统注册方法主要应用于室内范围的局限性,提出并实践将GPS与惯性传感器组合进行注册,并成功应用于户外环境下ArGIS混合跟踪注册技术。设计了一套户外注册单元硬件设备系统,解决了不同设备间涉及的数据同步与坐标融合问题。实验结果表明,该系统的注册精度能够达到校园环境下注册的技术要求。     

Enabling Spatially Aware Mobile Applications

Recently, increasing numbers of mobile phones are appearing on the market that feature advanced navigation capabilities: embedded GPS receivers for global positioning, integrated digital compasses for detecting the heading of the device, or accelerometer‐based tilt sensors will potentially enable upcoming and future mobile phones to measure their location and orientation in 3D space. In this paper, we present an application framework for building spatially aware mobile applications – applications that visualize, process or exchange geospatial information – on mobile phones equipped with such features. The core component of the framework is a novel, platform‐independent XML data exchange format for the interface between application server and mobile device that describes the geographic vicinity of the user. The format enables a variety of new mobile interaction styles and user interface types – from traditional text‐based local search and information interfaces to innovative real‐time user interfaces like Geo‐Wands and Smart Compasses.     

Location-based services: technical and business issues

Geographical Information System (GIS) and Global Positioning System (GPS) technologies are expanding their traditional applications to embrace a stream of consumer-focused, location-based applications. Through an integration with handheld devices capable of wireless communication and mobile computing, a wide range of what may be generically referred to as 'Location-Based Services' (LBS) may be offered to mobile users. A location-based service is able to provide targeted spatial information to mobile workers and consumers. These include utility location information, personal or asset tracking, concierge and route-guidance information, to name just a few of the possible LBS. The technologies and applications of LBS will play an ever increasingly important role in the modern, mobile, always-connected society. This paper endeavours to provide some background to the technology underlying location-based services, and to discuss some issues related to developing and launching LBS. These include whether wireless mobile technologies are ready to support LBS, which mobile positioning technologies can be used and what are their shortcomings, and how GIS developers manipulate spatial information to generate appropriate map images on mobile devices (such as cell phones and PDAs). In addition, the authors discuss such issues as interoperability, privacy protection and the market demand for LBS. Electronic Publication     

无标识纸质地图增强现实技术研究与实现

纸质地图因其通用性和全局性特点在地理环境的认知过程中具有重要意义,经过增强现实技术融合将会在信息载负量和可视化维度等方面实现突破。文中简述无标识纸质地图增强现实系统的技术原理,提出一种纸质地图无标识配准方法,归纳总结纸质地图增强现实表达方法及其作用,研究纸质地图人机交互方法,实现无标识纸质地图与增强现实技术的融合,增强传统纸质地图的认知功能。     

移动增强现实关键技术及应用

增强现实技术是虚拟现实领域近年来的一个研究热点,并在其关键技术上取得了一定的突破。随着移动终端(如智能手机、个人数字助理等)上GPS定位、电子罗盘和加速计、摄像机等功能模块的实现,将增强现实技术应用到移动终端已成为可能。本文首先对移动增强现实近几年的发展状况进行了总结,然后,对移动增强现实的关键技术和应用领域做了详细阐述,最后提出了移动增强现实当前发展所面临的问题。     

Accuracy of iPhone Locations: A Comparison of Assisted GPS,WiFi and Cellular Positioning

The 3G iPhone was the first consumer device to provide a seamless integration of three positioning technologies: Assisted GPS (A‐GPS), WiFi positioning and cellular network positioning. This study presents an evaluation of the accuracy of locations obtained using these three positioning modes on the 3G iPhone. A‐GPS locations were validated using surveyed benchmarks and compared to a traditional low‐cost GPS receiver running simultaneously. WiFi and cellular positions for indoor locations were validated using high resolution orthophotography. Results indicate that A‐GPS locations obtained using the 3G iPhone are much less accurate than those from regular autonomous GPS units (average median error of 8 m for ten 20‐minute field tests) but appear sufficient for most Location Based Services (LBS). WiFi locations using the 3G iPhone are much less accurate (median error of 74 m for 58 observations) and fail to meet the published accuracy specifications. Positional errors in WiFi also reveal erratic spatial patterns resulting from the design of the calibration effort underlying the WiFi positioning system. Cellular positioning using the 3G iPhone is the least accurate positioning method (median error of 600 m for 64 observations), consistent with previous studies. Pros and cons of the three positioning technologies are presented in terms of coverage, accuracy and reliability, followed by a discussion of the implications for LBS using the 3G iPhone and similar mobile devices.     

Automated Production of Schematic Maps for Mobile Applications

The advent of high‐end miniature technology, together with the increasing availability of large scale digital geographic data products, has created a demand for techniques and methodologies that assist in the automated generation of maps specifically tailored to mobile GIS applications. This paper concerns itself with the problem of automatic generation of schematic maps. Schematic maps are diagrammatic representations based on linear abstractions of networks. In the context of mobile mapping they are seen as being a particularly useful means of displaying transportation networks. This paper describes an algorithm that automates the production of schematic maps. The algorithm makes use of the simulated annealing optimisation technique. An implementation of the algorithm is also presented, together with experimental results.     

Toward green cartography & visualization: a semantically-enriched method of generating energy-aware color schemes for digital maps

ABSTRACT

We introduce a semantically-enriched method of generating color schemes for various types of digital maps that reduces the energy consumption of the display device while preserving the quality of the original design. Energy-aware design intersects two important trends in cartography. First, as more maps are viewed today on mobile, battery life has become a central constraint influencing design. Second, there is increasing need for green computing, which encourages the efficient use of energy to limit environmental impacts. This paper focuses on one important aspect of energy-aware cartography: color design. Existing research on energy-aware color adjustment methods apply broadly to images or websites. However, the colors used in maps have more structured semantic relationships than most documents viewed on mobile devices, and efforts to account for these relationships while reducing energy consumption are limited. To fill this gap, we mathematically formalize energy-aware map-color adjustment as a constrained optimization problem: we define energy consumption as the objective function and model the preservation of semantic relationships as the search constraints. We evaluate our proposed method against a common color dimming method using four maps with different semantic relationships. The evaluation suggests that our proposed method better preserves the original color semantics.     

Satellite emission radio interferometric earth surveying series—GPS geodetic system

The satellites of the Global Positioning System (GPS) offer an important new geodetic resource making possible a highly accurate portable radio geodetic system. A concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) makes use of GPS radio transmissions without any satellite modifications. By employing the technique of very long baseline interferometry (VLBI) and its calibration methods, 0.5 to 3 cm three dimensional baseline accuracy can be achieved over distances of 2 to 200 km respectively, with only 2 hours of on-site data acquisition. The use of quasar referenced ARIES Mobile VLBI to establish a sparse fundamental control grid will provide a basis for making SERIES GPS measurements traceable to the time-invariant quasar directions. Using four SERIES stations deployed at previously established ARIES sites, allows the GPS satellite apparent positions to be determined. These apparent positions then serve as calibrations for other SERIES stations at unknown locations to determine their positions in a manner traceable to the quasars. Because this proposed radio interferometric configuration accomplishes its signal detection by cross-correlation, there is no dependence upon knowledge of the GPS transmitted waveforms which might be encrypted. Since GPS radio signal strengths are 10⁵ stronger than quasar signals, a great reduction in telecommunications sophistication is possible which will result in an order of magnitude less cost for a SERIES GPS station compared to a quasar based mobile VLBI system. The virtually all-weather capability of SERIES offers cost-effective geodetic monitoring with applications to crustal dynamics and earthquake research.     

A map-matching algorithm dealing with sparse cellular fingerprint observations

ABSTRACT

The widespread availability of mobile communication makes mobile devices a resource for the collection of data about mobile infrastructures and user mobility. In these contexts, the problem of reconstructing the most likely trajectory of a device on the road network on the basis of the sequence of observed locations (map-matching problem) turns out to be particularly relevant. Different contributions have demonstrated that the reconstruction of the trajectory of a device with good accuracy is technically feasible even when only a sparse set of GNSS positions is available. In this paper, we face the problem of coping with sparse sequences of cellular fingerprints. Compared to GNSS positions, cellular fingerprints provide coarser spatial information, but they work even when a device is missing GNSS positions or is operating in an energy saving mode. We devise a new map-matching algorithm, that exploits the well-known Hidden Markov Model and Random Forests to successfully deal with noisy and sparse cellular observations. The performance of the proposed solution has been tested over a medium-sized Italian city urban environment by varying both the sampling of the observations and the density of the fingerprint map as well as by including some GPS positions into the sequence of fingerprint observations.     

网络RTK流动站系统集成的探讨

对国外、国内多种类型GPS接收机，按不同的通讯链路、接入不同CORS系统的相关配置工作进行分析、归纳，从设备选型、系统集成、CORS系统的接入三个方面对网络RTK流动站系统的集成进行了探讨。     

移动电子地图中伪3D可视化设计

定义了移动电子地图中伪3D可视化概念,提出伪3D可视化模型,并设计了快速的三维投影变换算法。进行了移动电子地图的伪3D可视化实验设计,并给出了可视化性能测试结果。     

基于位姿传感器的户外ARGIS注册技术

针对传统基于计算机视觉注册方法的局限性,提出并实践将GPS与位姿传感器进行组合应用于户外环境下增强现实地理信息系统的注册过程。设计了一套在户外注册单元硬件设备系统,推导阐释了实虚融合坐标转换关系,解决了不同设备间涉及的硬件配准集成问题。实验结果表明,该系统的实时性与准确性指标能够达到校园环境下户外注册的技术要求。     

基于GPS/GPRS/GIS的车辆监控系统

发挥GPRS分组交换技术具有高速、实时、网络覆盖范围广的特点，利用车栽GPS实时快速定位与GIS直观地对地理数据跟踪显示的优势，实现移动体与管理中心之间实时在线及信息互传的智能化远程监控、调度和管理。本文设计和介绍了基于GPS，GPRS，GIS技术集成的车辆定位与监控系统的主要技术路线。     

MapSource与GoogleEarth在测量中的整合应用

GPS和航空影像在现代测量中已成为一种不可或缺的技术手段,如何能更好地利用现有的我们能掌控的技术资源,让它为我们的测量服务呢?在这里我根据以往的工作经验及对GPS手持机处理软件MapSource和Google Earth的使用情况,初步探讨这两种软件的整合及给我们测量工作带来的益处,尚需说明的是本文只是想起到一个抛砖引玉的作用,希望能给大家带来一点有益的思考.     

多传感器与道路网数据用于汽车导航的研究

对车载导航系统中GPS接收机，车论计数器和电子罗盘传感器数据与导航电子地图所提供的道路网络数据进行了综合处理，建立了道路网络数据的网络拓扑关系，在此基础上提出了基于道路网络拓扑关系，利用GPS接收机，车轮计数器和电子罗盘传感器对汽车进行实时定位的算法。最后，对导航中汽车的定位误差进行了分析。实验证明，GPS接收机，车轮计数器和电子罗盘传感器与道路网络数据综合，在导航过程中能够补偿GPS信号技失，实时、高精度、高可靠性地确定汽车的位置。     

福建省生态环境综合系列图编制

福建省生态环境综合系列图是数字福建应用项目《福建省生态环境动态监测与管理系统》中数据库建设的一个重要基础工作,包括生态环境类型图、生态环境评价图、生态功能区划图以及地势图、地貌图、土壤图、植被图、土地利用图等。编制工作是在参考各种图件和文字等资料基础上,以遥感(LandSatETM)为主要信息源,根据影像特征的差异勾绘生态环境单元并记录各单元一系列相关信息,根据单元图属性派生其它图(地势图除外)。编制过程中着重解决了各专题图的分类系统和编码系统、多源信息复合、遥感综合系列制图与地图演绎法结合应用、3S技术的综合应用、多种制图技术的综合应用等问题。     

Accuracy of iPhone Locations: A Comparison of Assisted GPS, WiFi and Cellular Positioning

The 3G iPhone was the first consumer device to provide a seamless integration of three positioning technologies: Assisted GPS (A-GPS), WiFi positioning and cellular network positioning. This study presents an evaluation of the accuracy of locations obtained using these three positioning modes on the 3G iPhone. A-GPS locations were validated using surveyed benchmarks and compared to a traditional low-cost GPS receiver running simultaneously. WiFi and cellular positions for indoor locations were validated using high resolution orthophotography. Results indicate that A-GPS locations obtained using the 3G iPhone are much less accurate than those from regular autonomous GPS units (average median error of 8 m for ten 20-minute field tests) but appear sufficient for most Location Based Services (LBS). WiFi locations using the 3G iPhone are much less accurate (median error of 74 m for 58 observations) and fail to meet the published accuracy specifications. Positional errors in WiFi also reveal erratic spatial patterns resulting from the design of the calibration effort underlying the WiFi positioning system. Cellular positioning using the 3G iPhone is the least accurate positioning method (median error of 600 m for 64 observations), consistent with previous studies. Pros and cons of the three positioning technologies are presented in terms of coverage, accuracy and reliability, followed by a discussion of the implications for LBS using the 3G iPhone and similar mobile devices.