共查询到18条相似文献，搜索用时 140 毫秒
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采用载波无几何组合和星间单差无电离层组合的历元间高次差作为周跳检验量,因组合观测值中不包含伪距,其理论噪声与波长相比几乎可以忽略。利用两种组合观测值联合进行周跳探测,可避免各自的探测盲点。将两个载波组合联立进行周跳的求解,由于组合噪声较小,直接取整即可求得周跳的大小。提出的方法在一定程度上克服了传统周跳探测与修复算法中,由于引入伪距带来的探测能力不强、修复精度不高等问题。通过对IGS站观测数据模拟周跳探测与修复情况的统计,新提出算法的周跳探测成功率为99%,周跳修复成功率为94%。 相似文献
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使用GPS进行测量,可达到很高的精度,其主要原因是消除了同步观测站的空间相关误差。最主要的误差是对流层、电离层延迟误差、卫星星历误差以及选择可用性引起的误差。对于同步观测的接收机来说,误差的高相关性简单地表明,信号穿过的大气层基本相同,星历误差投影基本相同,等等。双差分消除了这些相关误差。对于伪距观测、载波相位及后处理或实时定位,的确如此。可以认为,反映在基准站和运动站的误差相同。 相似文献
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基于多测站观测数据,采用伪距相位差组合和伪距多径组合方法,分析了GPS、Galileo、BDS和QZSS 4个系统伪距测量噪声和多径误差,比较了各系统内部信号数据质量以及系统间兼容信号数据质量。结果表明:GPS系统中L2C信号伪距测量精度要优于L2信号;Galileo系统中E5信号伪距测量精度最优,其E1和E5a信号伪距测量精度分别优于GPS/QZSS L1和L5信号;QZSS信号伪距测量精度与GPS信号基本一致;BDS系统三频信号伪距多径中均存在与高度角相关的系统性偏差,最大可达1m,且其三类卫星伪距测量精度有所差异,相同高度角条件下,GEO卫星伪距测量精度最优,IGSO卫星次之,MEO卫星最差。 相似文献
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The problems of recording the ionospheric response to tropical cyclones (TCs) and the possibilities for detecting such a response
using GPS (Global Positioning System) signals are discussed. Investigations of ionospheric effects of tropical cyclones with
the use of different geophysical methods and technologies of GPS application for remote diagnostics of the ionosphere are
reviewed. The results of investigating the action of tropical cyclones on the Earth’s ionosphere on the basis of measurements
of variations in the total electron content at the global network of ground-based double-frequency GPS receivers are presented.
It is shown that (a) the recording of tropospheric effects in the ionosphere is associated with the difficulties of detecting
weak disturbances and their identification against the general background of variations and with the problems of identification
of sources of such disturbances; (b) geomagnetic storms mask the effects of tropospheric disturbances in the upper ionosphere;
and (c) when identifying the ionospheric effects of tropical cyclones, one must pay the bulk of attention to the search for
the enhancement of the intensity of disturbances in ionospheric parameter variations. 相似文献
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Y. Gao 《Marine Geodesy》2013,36(4):279-288
Global positioning system (GPS) has found applications in various areas including marine geodesy. GPS positioning accuracy, however, is greatly degraded by GPS ephemeris and clock errors, particularly errors due to Selective Availability (SA). Thus, it is crucial to use precise ephemeris and clock corrections for users who require high position accuracy. Presently, precise ephemeris and clock corrections are available only in post‐mission. This paper investigates the generation of precise real‐time ephemeris and clock corrections and the positioning accuracy using them. In this research, precise real‐time ephemeris is generated from accurate dynamic orbit prediction and clock corrections are calculated using instantaneous GPS measurements. Numerical analysis using data from an actual GPS tracking network is performed that indicates use of precise ephemeris and clock corrections can improve the positioning accuracy to the one meter level. This accuracy is attainable in real‐time as the precise real‐time ephemeris and clock corrections become available in the future. 相似文献
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