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271.
272.
Akshay O. Jain Tejaskumar Thaker Ashish Chaurasia Parth Patel Anupam Kumar Singh 《国际地球制图》2013,28(11):1237-1256
AbstractShuttle Radar Topography Mission (SRTM-GL1), Advanced Space Borne Thermal Emission and Reflection Radiometer- Global DEM (GDEM-V2), recently released Advanced Land Observing Satellite (‘DAICHI’) DEM (AW3D30) and Indian National Cartosat-1 DEM v3 (CartoDEM-V3.1) provide free topographic data at a 30-m resolution for Indian peninsula. In this research study, the vertical accuracy of DEM is evaluated for above data-sets and compared with high accuracy dual frequency GNSS of a millimetre accuracy. The extensive field investigation is carried out using a stratified random fast static DGPS survey for collecting 117 high accuracy ground control points in a predominantly agriculture catchment. Further, the effect of land cover, slope and low-lying coastal zone on DEM vertical accuracy was also analysed and presented in this study. 相似文献
273.
简要介绍Vipersat系统独特的动态SCPC技术和上行切换策略,为“陆态网络”项目提供优质的卫星通信网络平台.在SCPC+TDMA双模工作体制下,“陆态网络”基准站和重力站的各类数据业务得到安全、可靠、有效地传输;Vipersat系统的带宽管理能力有效提高带宽利用率,服务质量提高. 相似文献
274.
275.
Antonio Tomás Mozas-Calvache Francisco Javier Ariza-López 《International journal of geographical information science》2013,27(11):2170-2187
ABSTRACTThe sharing of Global Navigation Satellite System (GNSS) tracks on the Internet is increasing enormously. Every day a great number of users capture routes using different devices and share these data. Individually these tracks present a poor positional accuracy because these devices obtain positions with accuracy of about 5-10 metres. In addition, they are usually captured for navigation and not for surveying. However, we can take advantage of the great quantity of tracks of the same linear element in order to obtain a more accurate solution. This study analyses this possibility using a wide set of tracks obtained in known conditions. We emulated those tracks obtained by Volunteered Geographic Information (VGI) users and we compared the mean axis obtained using all tracks with others obtained from a more accurate source. Additionally, we analyse the displacement of other axes obtained by varying several parameters such as the number of tracks and their length or by dividing the route into sections in function of sinuosity, etc. The results have shown an improved 3D mean axis and the viability of the method proposed in this study in order to use axes obtained from several tracks in maps at certain scales. 相似文献
276.
GNSS垂向形变场信息提取的尝试 总被引:1,自引:0,他引:1
一定条件下GNSS流动复测资料可为我们揭示地形变提供必要的依托,但由于垂向分量观测误差较大而没有被恰当地利用。利用华北地区1999-2007年的4期资料,从形变场的连续变化角度出发,提出了利用多核函数进行解析与滤波的方法,理论与结:器表明:①可获得垂直运动场的数学解析;②可实现对垂向运动场不同层次的滤波与信息分离;③当流动测站具有一定的空间密度、一定数量的复测结果和时间长度则可获得较可靠的形变信息。最后利用华北地区GNSS流动观测资料给出了实际算例与初步分析结果。 相似文献
277.
A New Data Processing Strategy for Huge GNSS Global Networks 总被引:2,自引:4,他引:2
In Global Positioning System (GPS) data analyses, large networks are usually divided into sub-networks to solve the conflict between increasing amounts of data and limited computer resources, although an integrated analysis would provide better results. This conflict becomes even more critical with the increasing number of stations, and low-Earth-orbiting satellites and the Galileo system coming into operation. The major reason is that a huge number of ambiguity parameters are kept in the normal equation for sequential integer ambiguity fixing. In this paper, the problem is solved by a special procedure of parameter elimination for both real-valued and ambiguity-fixed solutions, based on an adapted ambiguity-fixing approach where the covariance-matrix of ambiguity parameters is not required anymore. It is demonstrated that, with the new strategy, the required memory can be reduced to one-tenth and the computation time to at least one-third compared to the existing methods, and huge GPS networks with several hundred stations can be processed efficiently on a personal computer. 相似文献
278.
利用2011日本东北Mw9.0地震和2008汶川Mw7.9地震若干台站的高频(1 Hz)GNSS观测资料,通过精密单点定位方法解算出地震发生时的位移形变波形。对位移波形一阶差分得到震时高频GNSS速度时间序列,采用S变换谱的方法对该速度时序进行地震波到时的拾取,即震相识别。将地震波拾取结果用于震中位置和发震时刻反演,并与美国地质调查局USGS公布的资料对比。结果发现,两者日本地震震中位置相差约16 km,发震时刻相差约0.7 s;汶川地震震中相差约4 km,发震时刻相差约0.4 s。 相似文献
279.
??????GNSS??????????????????????????α??????INS????GNSS??????????????????????????????????α??????????????????????????INS?????α??α????????????GNSS?????????????????????й?????????????????????????????????????GNSS??????????????????????????????????????????α????????????????????? 相似文献
280.
???GNSS/Pseudolites???????α????????????????????????????????μ?GNSS????α????????????,??????????λ??????????????????????????????????????????????????????????????????α??????????????????????????????????????仯????Ч????????????????????????λ????????????μ?PDOP????????????????????仯?????????????PDOP?????????????????????????????????ЧЭ?????????????????????????????????????????Ч????α???????GNSS?????Ч?????? 相似文献