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1.
Chigomezyo M. Ngwira Lee-Anne McKinnell Pierre J. Cilliers 《Journal of Atmospheric and Solar》2010,72(9-10):718-725
Radio wave scintillation due to the presence of ionospheric irregularities can cause fading and phase variation of L-band navigation signals such as those used by the Global Positioning System (GPS). The high-latitude regions experience increased scintillation events under geomagnetically disturbed conditions, particularly during solar maximum. This paper presents phase scintillation measurements observed at the South African Antarctic polar research station during solar minimum conditions. In addition, a multi-instrument approach is shown in which the scintillation events are associated with auroral electron precipitation. Furthermore, it is shown that external energy injection into the ionosphere is an important factor in the development of irregularities producing scintillation. 相似文献
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Pawel Wielgosz Andrzej Krankowski Rafal Sieradzki Dorota A. Grejner-Brzezinska 《Acta Geophysica》2008,56(4):1147-1161
Real Time Kinematic (RTK) GPS positioning over longer distances requires a support of atmospheric (ionospheric and tropospheric) corrections, since the atmospheric errors decorrelate with the growing distances and cannot be completely eliminated by double differencing of the satellite observations. Currently, the most commonly used approach is to derive the atmospheric corrections at the reference station network and provide them in real time to the roving receiver. Another solution, proposed here, is to use predictive atmospheric models in order to derive the atmospheric corrections. This paper presents the test results of the performance assessment of the predictive ionosphere model (UWM-IPM) application to medium-range RTK positioning. The rover data collected within 25 to 67 km from the closest reference station were processed in the kinematic mode with the support of the ionospheric corrections derived from the UWM-IPM model. The RTK solution was derived in both single-and multi-baseline modes, and compared to the two reference solutions obtained without the ionospheric corrections. All numerical tests were carried out using the MPGPS software developed in cooperation with The Ohio State University; a recent extension to the software, developed at the University of Warmia and Mazury in Olsztyn, introduces the predictive ionosphere model to the RTK solution. The test results are very promising, and indicate that predicted ionosphere corrections can effectively support medium-range RTK positioning, and allow for fast ambiguity resolution over distances of several tens of kilometers under moderate ionospheric conditions. 相似文献
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地震现场救援要素众多,部署分散,为了统一管理救援要素,综合展示救援态势,设计一种基于B/S架构的地震应急救援态势标绘系统,采用Google Maps API v3实现前端Web GIS功能,加载谷歌地图,标绘震情灾情和救援要素信息,通过AJAX方式与服务器端进行数据交互,保存要素信息或者获取服务器端数据,系统设计聊天室功能,登录用户可以在线实时交流。本系统对使用环境要求低,支持多种移动终端,适合地震现场人员使用,实现了分布式要素标绘功能,是地震现场救援行动的有效辅助决策工具。 相似文献
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R. Orús M. Hernndez-Pajares J. M. Juan J. Sanz M. García-Fernndez 《Journal of Atmospheric and Solar》2002,64(18)
The existence of a worldwide international GPS service (IGS) permanent network of dual-frequency receivers makes the computation of global ionospheric maps (GIMs) of total electron content (TEC) feasible. The GIMs computed by the IGS Associate Analysis Centers on a daily basis and by other kinds of forecast GIMs, which can be computed from, for instance, the international reference ionosphere (IRI) model, and the GPS broadcast models in the navigation message, can be applied to a broad diversity of fields, for instance as, navigation and time transfer.In this context, the performance of different kinds of models are presented in order to determine the accuracy of the different GIM. This is carried out by comparison with the TOPEX data that provides an independent and precise (at the level of few TECU) vertical TEC determination over the oceans and seas. Thus, the obtained accuracies, in terms of global relative error, ranging from 54% corresponding to the GPS broadcast model, to about 41% corresponding to IRI climatological model, and to less than 30% corresponding to GPS data driven models. 相似文献
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在灾后救援中,交通系统既是救援物资运输的通道,也是抢救和安置受伤群众的重要保证。然而破坏性地震后,交通系统的破坏以及急增的运输量给伤亡人员的转移和救援物资的运送都带来了极大的困难。因此,在灾后第一时间给出最优路径的建议,帮助救援队快速高效的进行灾后的救援工作,有重要的意义。考虑震后条件及应急需求,对已有的最短路径,最大容量路径进行改进。利用Dijkstra算法和深度优先算法,考虑路段的通行能力、抢修效率和应急期限,给出了以最大运输量为目标的最优路径的评价方法,为震后应急决策提供技术支持。 相似文献
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利用改进的自动经验基线校正方法SMBLOC,对2016年8月24日意大利佩鲁贾MW 6.2级地震震中周围约60 km内的近场强震记录进行基线校正并尝试给出同震位移场,与GPS观测结果进行对比分析,分别独立和联合两种资料反演震源滑动模型,并根据震源模型进一步给出全空间预测位移场分布.研究结果表明:(1)两种不同的资料给出的水平位移场幅值均为cm级,且均表明断层的错动以正断为主.(2)两种同震位移场分别独立和联合反演所得的震源静态滑动范围基本一致,最大滑动均发生在震中东北侧,强震模型表现出明显的双事件特征,较大滑动分布在震中东北侧和东南侧,GPS模型在震中东南侧的滑动相对较小,其双事件特征不明显.两种模型的最大滑动量分别为0.96 m和0.86 m,较为一致,反演的矩震级均在MW 6.3左右.(3)根据震源滑动模型计算所得的佩鲁贾地震全空间预测的水平同震位移场中最大位移分布区域与震后报告中受灾严重的地区基本一致.表明在一定的条件下,利用SMBLOC方法解算震级较小的MW 6.0左右地震强震记录的同震位移场,并反演震源滑动模型具有一定的可行性,且其同震位移场和滑动模型可为震后灾害快速评估、救援力量分配、余震趋势判定等快速应急响应工作提供参考依据. 相似文献
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Anthony Astoul Christopher Filliter Eric Mason Andrew Rau-Chaplin Kunal Shridhar Blesson Varghese Naman Varshney 《Bulletin of Earthquake Engineering》2013,11(6):1973-2005
An automated, real-time, multiple sensor data source relying and globally applicable earthquake loss model and visualiser is desirable for post-event earthquake analysis. To achieve this there is a need to support rapid data ingestion, loss estimation and integration of data from multiple data sources and rapid visualisation at multiple geographic levels. In this paper, the design and development of the Automated Post-Event Earthquake Loss Estimation and Visualisation (APE-ELEV) system for real-time estimation and visualisation of insured losses incurred due to earthquakes is presented. A model for estimating ground up and net of facultative losses due to earthquakes in near real-time is implemented. Since post-event data is often available immediately from multiple disparate sources, a geo-browser is employed to facilitate the visualisation and integration of earthquake hazard, exposure and loss data. The feasibility of APE-ELEV is demonstrated using a test case earthquake that occurred in Tohoku, Japan (2011). The APE-ELEV model is further validated for ten global earthquakes using industry loss data. 相似文献
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CDSN台SEED数据格式的软件开发 总被引：2，自引：0，他引：2
本软件可以把miniSEED格式数字地震数据转换为标准的SEED格式数据，满足了台站及台网的要求，提高了台站的技术管理水平和工作效率。 相似文献
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卫星定位导航系统在地震应急救援中的应用 总被引：3，自引：0，他引：3
在对地震灾害特点综合分析的基础上,分析了地震应急响应与救援决策中的关键性问题。认为震害的规模、程度、空间分布和灾情发展趋势,以及快速获取灾情信息已成为整个地震应急响应和救援决策的关键;而对灾情空间分布及其不同灾情程度位置的确定是救援决策的先导与重要环节。卫星定位导航技术在地震应急搜救的信息快速获取、应急响应、救援决策、指挥、搜索与营救等救援行动的整个过程中,都将发挥其强大的功能。建议研发中国北斗灾害应急救援导航与指挥决策系统,包括地震灾情快速获取、快速判定和决策定位导航技术系统、地震救援指挥调度技术系统和应急救援物流定位导航技术系统建设;研发北斗灾害应急救援导航装备,包括自主定位导航幸存者搜索和营救设备研发和国内外巨灾救援专用定位与导航系统研发。 相似文献
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介绍了福建省30个GPS连续观测基准站的勘选过程。在勘选过程中,应用TEQC数据预处理软件,对预选的基准站进行24小时的测试,并做出质量分析。从而勘选出满足规范、可靠、安全、科学的GPS连续观测基准站站址,为GPS连续观测基准站建站提供依据。 相似文献
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地震前兆数据一直是地震分析预报必不可少的重要数据资源。随着辽宁省地震前兆台站数字化技术改造的开展，地震前兆模拟记录将逐步被数字化记录所取代。我们结合数字化技术改造的实际情况，采用先进的网络关系数据库模型构造了辽宁省数字地震前兆数据库。该数据库直接面向整个地震系统，为地震预报提供详实的数据服务和先进的研究手段。本文对数据库系统、数据库总体设计及数据共享服务也进行了深入研究和讨论。 相似文献
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Tidally induced sub-daily Earth Rotation Parameters (ERP) variations, when not properly accounted for, can cause apparent orbit and ERP rate errors, which can significantly exceed the IGS solution errors. All International GPS Service (IGS) Analysis Centers currently apply the conventional sub-daily ERP model in their transformations from ITRF (International Terrestrial Reference Frame) to ICRF (International Celestial Reference Frame), both of which are used for IGS global analyses. However, some IGS Analysis Centers did not apply the sub-daily ERP model when transforming ICRF orbit solutions to ITRF, which is used for IGS orbit/clock products. This transformation inconsistency can cause significant orbit RMS differences that could exceed the 5-cm level. Independent ERP rate solutions are sensitive even to small errors in the sub-daily ERP model, and can be used to verify the sub-daily ERP model at, or below 0.1 mas/day precision level.The Precise Point Positioning (PPP) via precise station position solutions with the IGS orbit/clock combined products, provides an ideal interface to access the IGS realization of ITRF. PPP also yields precise station clock and tropospheric zenith delays (TZD) solutions, all at the sub-cm precision level. However, when using IGS orbit/clock products it is important that the same convention be used with respect to sub-daily ERP. Otherwise, the solutions of station navigation positions, station clocks and TZD's will be affected by significant errors that could exceed the 1-cm level. 相似文献
17.
Ali Kiliçoğlu Ahmet Direnç Hasan Yildiz Murat Bölme Bahadir Aktuğ Mehmet Simav Onur Lenk 《Studia Geophysica et Geodaetica》2011,55(4):557-578
Turkish regional geoid models have been developed by employing a reference earth gravitational model, surface gravity observations
and digital terrain models. The gravimetric geoid models provide a ready transformation from ellipsoidal heights to the orthometric
heights through the use of GPS/leveling geoid heights determined through the national geodetic networks. The recent gravimetric
models for Turkish territory were computed depending on OSU91 (TG-91) and EGM96 (TG-03) earth gravitational models. The release
of the Earth Gravitational Model 2008 (EGM08), the collection of new surface gravity observations, the advanced satellite
altimetry-derived gravity over the sea, and the availability of the high resolution digital terrain model have encouraged
us to compute a new geoid model for Turkey. We used the Remove-Restore procedure based on EGM08 and applied Residual Terrain
Model (RTM) reduction of the surface gravity data. Fast Fourier Transformation (FFT) was then used to obtain the residual
quasigeoid from the reduced gravity. We restored the individual contributions of EGM08 and RTM to the whole quasi-geoid height
(TQG-09). Since the Helmert orthometric height system is adopted in Turkey, the quasi-geoid model (TQG-09) was then converted
to the geoid model (TG-09) by making use of Bouguer gravity anomalies and digital terrain model. After all we combined a gravimetric
geoid model with GPS/leveling geoid heights in order to obtain a hybrid geoid model (THG-09) (or a transformation surface)
to be used in GPS applications. The RMS of the post-fit residuals after the combination was found to be ± 0.95 cm, which represents
the internal precision of the final combination. And finally, we tested the hybrid geoid model with GPS/leveling data, which
were not used in the combination, to assess the external accuracy. Results show that the external accuracy of the THG-09 model
is ± 8.4 cm, a precision previously not achieved in Turkey until this study. 相似文献
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利用2010—2015年陆态网络GPS连续观测站的三维站坐标时序资料, 在采用最大似然估计MLE方法计算得到云南地区GPS基准站三维站坐标分量最优噪声模型的基础上, 进一步定量对比分析了有色噪声和白噪声模型下陆态网络GPS连续站速度场稳定性与时间序列长度的关系。 结果表明: 在闪烁噪声模型下, 中国大陆大部分地区GPS连续站1 a时段的速度不确定度大。 而随着时间的逐年累积, 闪烁噪声模型下的速度不确定度与同时段白噪声模型下的差异逐步减小, 闪烁噪声模型下3～4 a时段的速度不确定度与同时段白噪声模型的差异小于0.2 mm。 研究说明在有色噪声模型下要获得高精度的速度场需要3～4 a的观测数据, 白噪声模型下GPS速度场精度可靠可信的前提是采用不少于3～4 a的数据。 相似文献
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应用黑龙江省数字遥测地震台网2002-2006年目录数据,对绥棱采石场附近爆破进行重新定位,对比GPS实测位置,研究该黑龙江省数字地震台网“十五”数据处理软件系统（MSDP 人机交互系统）提供的5种定位程序,初步认为,对于网内浅源地震定位,单纯型法优于其他方法。 相似文献