共查询到20条相似文献,搜索用时 15 毫秒
1.
TEQC软件对GPS数据质量的评定及软件界面的开发 总被引:8,自引:0,他引:8
本文主要介绍用于GPS数据转换、编辑和质量检查的共享软件TEQC(Translate/Edit/Quality Check)。作为例子,对一GPS数据进行质量检查。并针对TEQC软件人机交互性差的缺点,进行了软件界面程序的初步开发。 相似文献
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TEQC: The Multi-Purpose Toolkit for GPS/GLONASS Data 总被引:31,自引:11,他引:20
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船舶可视化和分析在现代航海管理领域中发挥着重要作用。鉴于目前主流的船舶符号栅格表达方式存在失真、不易交互等弊端,本文提出一种面向大范围船舶实时动态数据的矢量标绘方法。基于时空GIS技术实时接入船舶数据流,创建一个不断更新的船舶要素服务;在前端通过WebSocket建立与服务间的双向通信,低时延获取最新船舶定位信息;并结合多空间尺度表达规则和标绘算法进行符号重绘,实现对船舶位置、尺寸、航向在不同显示级别下的精确表达。测试证明,该方法可以有效支撑较大地理范围内船舶数据的动态可视化,满足船舶避碰、海事管理和应用分析的需要。 相似文献
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Journal of the Indian Society of Remote Sensing - The proliferation of Geographic Information Systems of varying capacity and capabilities combined with the ever increasing need for fast and... 相似文献
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A new companion for Mercator 总被引:1,自引:1,他引:0
Waldo Tobler 《制图学和地理信息科学》2018,45(3):284-285
The inappropriate use of the Mercator projection has declined but still occasionally occurs. One method of contrasting the Mercator projection is to present an alternative in the form of an equal area projection. The map projection derived here is thus not simply a pretty Christmas tree ornament: it is instead a complement to Mercator’s conformal navigation anamorphose and can be displayed as an alternative. The equations for the new map projection preserve the latitudinal stretching of the Mercator while adjusting the longitudinal spacing. This allows placement of the new map adjacent to that of Mercator. The surface area, while drastically warped, maintains the correct magnitude. 相似文献
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R. Roelofs 《Journal of Geodesy》1947,21(4):336-342
Summary After a review of the main causes of the relative inaccuracy of solar observations as compared with star observations, a new
device—a “solar prism attachment” to be fitted over the objective of a normal theodolite—for increasing the accuracy and facilitating
the observations is described. The results of several practical observations are discussed. 相似文献
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L. A. Kivioja 《Journal of Geodesy》1983,57(1-4):146-151
The theodolite used in this method is completely leveled by using autocollimation from a free mercury surface. This eliminates the need for striding or hanging levels which are in conventional use to level the trunion axis of the theodolite. Mercury leveling is more accurate and can be performed in a much shorter time than leveling by the striding or hanging levels. In addition, this new method removes the unavoidable axis wobbles contaminating the observed horizontal angles between the star and the azimuth mark. The uncontrolled wobble errors affecting azimuths can be up to three arc seconds. The axis wobbles are removed by using autocollimation from an axis mirror which is perpendicular to the trunnion axis of the theodolite. Autocollimation coincidences from the mercury and from the axis mirror can be made within one or two tenths of an arcsecond. This new method and instrumentation surpasses the obtainable precision by the conventional first-order astro azimuth observations by reducing the unknown systematic wobble and level errors by one order of magnitude. 相似文献
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通过对野外地形图和断面图测量方法的研究,介绍基于地形图测绘的纵横断面图的测绘程序,并对该程序的主要功能和关键技术作详细的论述。在目前的测绘技术中,利用该方法能够在很大程度上提高纵横断面测绘的工作效率。 相似文献
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Michael P. Johnson 《Journal of Geographical Systems》2001,3(1):49-67
This paper presents a GIS-based decision support system prototype intended for use by public housing authority (PHA) administrators
and planners designing policy for housing mobility programs. Housing mobility programs enable low-income families, many of
whom live in government-operated public housing, to move to more desirable private-market rentals via rent subsidies. Unfortunately,
housing authority planners have limited ability to visualize alternative relocation schemes of cohorts of low-income families
or the impacts associated with these relocation policies. Thus, they are often not able to give highest-quality advice to
clients regarding places to search for private-market rental housing. Housing Location Planner assists PHA planners in three
ways: it analyzes spatial, demographic and housing market characteristics of the study area, selects certain portions of the
study area for input to an optimization model which generates alternative family allocations, and displays optimization model
results in a way that links decision variable values and objective function values. Housing Location Planner is seen as a
first step in the development of even more sophisticated multi-stakeholder spatial decision support systems for subsidized
housing planning in which one or more alternative allocations of families across a study area is chosen as a basis for policy
initiatives.
Received: 8 September 1999/Accepted: 23 October 2000 相似文献
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With the advent of new global navigation satellite systems (GNSSs) and new signals, GNSS users will rely more on them to obtain higher-accuracy positioning. Evil waveform monitoring and assessment are of great importance for GNSS to achieve its positioning, velocity, and timing service with high accuracy. However, the advent of new navigation signals introduces the necessity to extend the traditional analyzing techniques already accepted for binary phase-shift keying modulation to new techniques. First, the well-known second-order step thread model adopted by the International Civil Aviation Organization is introduced. Then the extended new general thread models are developed for the new binary offset carrier modulated signals. However, no research has been done on navigation signal waveform symmetry yet. Simulation results showed that, waveform asymmetry may also cause tracking errors, range biases, and position errors in GNSS receivers. It is thus imperative that the asymmetry be quantified to enable the design of appropriate error budgets and mitigation strategies for various application fields. A novel evil waveform analysis method, called waveform rising and falling edge symmetry (WRaFES) method, is proposed. Based on this WRaFES method, the correlation metrics are provided to detect asymmetric correlation peaks distorted by received signal asymmetry. Then the statistical properties of the proposed methods are analyzed, and a proper deformation detection threshold is calculated. Finally, both simulation results and experimentally measured results of Beidou navigation satellite system (BDS) M1-S B1Cd signal are given, which show the effectiveness and robustness of the proposed thread models. 相似文献
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本文分析了面向业务用户的地理信息服务集成存在的问题,总结了地理信息服务集成研究进展,讨论了面向业务用户的地理信息服务集成的概念、特征,提出了一个面向业务用户的地理信息服务语义集成框架和集成过程,并通过实例验证了本文的方法. 相似文献
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针对摄影测量误差分析中存在的问题,提出了一种新的误差分析方法,把计算机仿真技术用于摄影测 量误差分析中,对框幅式影像建立了误差仿真分析系统,并对卫星影像和航空影像进行了误差影响分析,得到了 许多有价值的结论。 相似文献
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A new model for GPS yaw attitude 总被引:7,自引:4,他引:3
Yoaz E. Bar-Sever 《Journal of Geodesy》1996,70(11):714-723
modeling of the GPS satellite yaw attitude is a key element in high-precision geophysical applications. This fact is illustrated here as a new model for the GPS satellite yaw attitude is introduced. The model constitutes a significant improvement over the previously available model in terms of efficiency, flexibility and portability. The model is described in detail and implementation issues, including the proper estimation strategy, are addressed. The performance of the new model is analyzed and an error budget is presented. Finally, the implementation of the yaw bias on the GPS satellites is reviewed from its inception until it reached a steady state in November, 1995. 相似文献
15.
In spite of the appearance of new measurement methods in geodetic survey, the importance of the bubble level has not decreased.
The increase of accuracy is one of the most important tasks of geodetic research. In this connection, the reliability of the
testing of high-precision bubble levels must also be increased. This purpose is served by an apparatus for testing bubble
vials which fulfills up-to-date demands. The smallest measurable rotation angle is 0.1 second of arc, the smallest measurable
displacement 0.01 mm. The values can be digitized. 相似文献
16.
An acquisition method is proposed which saves processing time and rapidly finds the Global Positioning System (GPS) satellite
with high receiving power. The idea is to combine two or more Coarse/Acquisition (C/A) codes to process acquisition, thus
called “multi-C/A code acquisition method.” The proposed method will change the procedure of conventional Fast Fourier Transform
acquisition slightly, and it has the capabilities to combine with other acquisition methods to perform signal acquisition
simultaneously. In order to show how this multi-C/A code acquisition method may improve the Time To First Fix at the cold
start, the real raw Intermediate Frequency data from a GPS software receiver are used to validate this multi-C/A code acquisition
method. The results show that this method can save at least 23% processing time and it is able to detect the satellite more
rapidly. 相似文献
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针对卫星导航用户观测数据模拟具有高精度、高采样率、强实时性的要求,该文在研究卫星导航定位系统工作原理的基础上,建立了卫星导航用户观测数据实时模拟系统。详细论述了卫星导航用户观测数据模拟的原理、流程及所用到的数学模型。考虑到观测数据模拟的时间约束特性,将模拟系统划分为非实时层、弱实时层和强实时层3层结构,并采用多线程的处理方法。模拟算例结果表明:该系统具有正确性和可靠性,满足强实时性要求,适用于卫星导航用户观测数据模拟。 相似文献
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A new machine learning paradigm for terrain reconstruction 总被引:1,自引:0,他引:1
《Geoscience and Remote Sensing Letters, IEEE》2006,3(3):382-386
Terrain models that permit multiresolution access are essential for model predictive control of unmanned aerial vehicles in low-level flights. The authors present the extreme learning machine (ELM), a recently proposed learning paradigm, as a mechanism for learning the stored digital elevation information to allow multiresolution access. We give results of simulations designed to compare the performance of our approach with two other approaches for multiresolution access, namely: 1) linear interpolation on Delaunay triangles of the sampled terrain data points and 2) terrain learning using support vector machines (SVMs). The results show that to achieve the same mean square error during access, the memory needed in our approach is significantly lower. Additionally, the offline training time for the ELM network is much less than that for the SVM. 相似文献