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随着卫星导航技术的不断进步,GNSS全球卫星导航系统得到了快速发展和广泛应用。概述了GNSS系统的发展历程及研究现状,介绍了目前全球四大卫星导航系统GPS、GLONASS、Galileo和COMPASS的概况与最新进展,讨论了GNSS系统未来的发展方向。 相似文献
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以我国西南地区44个GNSS站在ITRF2008框架下约6年的高精度GNSS坐标时间序列为例,研究CME对高精度GNSS坐标时间序列的影响。用PCA方法提取序列中的CME并分析其对高精度GNSS坐标时间序列特征参数的影响。研究结果表明,CME对高精度GNSS时间序列的振幅、相位、噪声类型及测站速率均有不同程度的影响,主要体现在滤波后44个测站N、E、U方向序列标准差分别提高75%、70%、57%;滤波前后测站U方向约50%的测站速率有1~2 mm的差异。可见,在高精度时间序列建模、地壳蠕动形变分析、毫米级参考框架建立等高精度GNSS数据应用领域中CME的影响不容忽视。 相似文献
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GNSS科学发展与前景 总被引:2,自引:0,他引:2
GNSS早已成为多学科研究的强大工具。着重介绍了近几年来GNSS系统及其观测技术,特别是数据处理方法和技术的重大发展,阐述了数据格式标准化的进展、全球与区域参考框架现状、参考框架对地壳运动研究的影响和IGS的产品等。同时对利用GNSS观测研究成果,主要是地壳运动的研究成果也作了较为详细的介绍。 相似文献
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张兴汉 《测绘与空间地理信息》2022,(12):184-187
针对当前Klobuchar与GIM两种常用电离层延迟改正模型对GNSS伪距单点定位精度的影响,采用自编软件进行了两种模型对GPS、BDS、Galileo各两个频率伪距单点定位精度的影响分析。实验结果表明,整体而言GPS和BDS采用GIM模型解算得到的伪距单点定位精度要优于Klobuchar模型,Galileo采用两种模型解算得到的伪距单点定位精度相当。 相似文献
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现代信息化战争要求后勤保障准确、快速、安全、可控,而GPS正是能够帮助后勤保障满足这些要求的有力手段之一。GPS在军事后勤保障中有着广泛的应用前景,既能够提高后勤运输保障效能,又能保持运输保障与作战部队的保障需求协调一致,它必将成为未来信息化战争的关键性技术。本文着重从GPS在军事后勤保障的应用入手,首先介绍GPS的组成和特点,然后分析GPS对军事后勤保障的影响作用、具体应用和主要特点,最后指出GPS目前在我国军事领域应用的局限性,并提出相应的几点建议。 相似文献
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The timing error between global navigation satellite system (GNSS) and inertial navigation system (INS) processes limits the integration performance in GNSS/INS integrated systems. In a deeply coupled system, this timing error affects not only the integrated navigation solution, but also the GNSS signal tracking. We propose a time-domain model of INS-aided second-order phase-locked loops (PLLs) in consideration of the INS aiding delay, and analyze the effect of INS aiding delay on the tracking errors in details. In addition, an integrated hardware deeply coupled system platform was developed to verify the impact of time delay on INS-aided PLLs. Simulation and field vehicles testing results demonstrate that the tracking error of the INS-aided PLL caused by aiding delay increases with the lengthening of the delay time, the compression of the bandwidth, and the increase in the acceleration. Testing results verify the proposed model. 相似文献
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低轨导航增强GNSS发展综述 总被引:1,自引:0,他引:1
低轨星座具有地面接收信号强度高、几何图形变化快的优势,能够与中高轨GNSS星座形成互补,对增强GNSS的精度、完好性、连续性和可用性具有显著优势,已成为当前卫星导航领域的关注热点。本文首先简要介绍了现有的GNSS增强系统;总结了国内外低轨导航增强星座发展现状;针对低轨导航增强,对比分析了高中低轨导航星座的优缺点;重点讨论了低轨导航增强在联合定轨、快速精密定位、空间天气监测和室内定位等方面带来的机遇;分析指出了低轨导航增强的空间段、地面段和用户段所面临的挑战。 相似文献
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In recent years, several studies have demonstrated the sensitivity of Global Navigation Satellite System (GNSS) station time
series to displacements caused by atmospheric pressure loading (APL). Different methods to take the APL effect into account
are used in these studies: applying the corrections from a geophysical model on weekly mean estimates of station coordinates,
using observation-level corrections during data analysis, or solving for regression factors between the station displacement
and the local pressure. The Center for Orbit Determination in Europe (CODE) is one of the global analysis centers of the International
GNSS Service (IGS). The current quality of the IGS products urgently asks to consider this effect in the regular processing
scheme. However, the resulting requirements for an APL model are demanding with respect to quality, latency, and—regarding
the reprocessing activities—availability over a long time interval (at least from 1994 onward). The APL model of Petrov and
Boy (J Geophys Res 109:B03405, 2004) is widely used within the VLBI community and is evaluated in this study with respect to these criteria. The reprocessing
effort of CODE provides the basis for validating the APL model. The data set is used to solve for scaling factors for each
station to evaluate the geophysical atmospheric non-tidal loading model. A consistent long-term validation of the model over
15 years, from 1994 to 2008, is thus possible. The time series of 15 years allows to study seasonal variations of the scaling
factors using the dense GNSS tracking network of the IGS. By interpreting the scaling factors for the stations of the IGS
network, the model by (2004) is shown to meet the expectations concerning the order of magnitude of the effect at individual stations within the uncertainty
given by the GNSS data processing and within the limitations due to the model itself. The repeatability of station coordinates
improves by 20% when applying the effect directly on the data analysis and by 10% when applying a post-processing correction
to the resulting weekly coordinates compared with a solution without taking APL into account. 相似文献
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Processing of data from global navigation satellite systems (GNSS), such as GPS, GLONASS and Galileo, can be considerably impeded by disturbances in the ionosphere. Cycle-slip detection and correction thus becomes a crucial component of robust software. Still, dealing with ionospheric cycle slips is not trivial due to scintillation effects in both the phase and the amplitude of the signals. In this contribution, a geometry-based approach with rigorous handling of the ionosphere is presented. A detailed analysis of the cycle-slip correction process is also tackled by examining its dependence on phase and code noise, non-dispersive effects and, of course, the ionosphere. The importance of stochastic modeling in validating the integer cycle-slip candidates is emphasized and illustrated through simulations. By examining the relationship between ionospheric bias and ionospheric constraint, it is shown that there is a limit in the magnitude of ionospheric delay variation that can be handled by the cycle-slip correction process. Those concepts are applied to GNSS data collected by stations in northern Canada, and show that enhanced cycle-slip detection can lead to decimeter-level improvements in the accuracy of kinematic PPP solutions with a 30-s sampling interval. Cycle-slip correction associated with ionospheric delay variations exceeding 50 cm is also demonstrated, although there are risks with such a procedure and these are pointed out. 相似文献
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层析模型在GNSS探测电离层中的研究进展 总被引:1,自引:0,他引:1
在利用全球导航卫星系统GNSS(GPS、GLONASS、Galileo等卫星定位系统)进行精密定位和导航时,电离层延迟误差是影响其精度和准确度的主要误差源之一,故对电离层模型研究至关重要。本文介绍了传统电离层模型的缺点,重点阐述了不同的电离层层析方法,同时分析了现在电离层层析方法所存在的主要问题,最后介绍了目前全世界电离层层析模型的研究展望。 相似文献
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Antenna thrust is a small acceleration acting on Global Navigation Satellite System satellites caused by the transmission of radio navigation signals. Knowledge about the transmit power and the mass of the satellites is required for the computation of this effect. The actual transmit power can be obtained from measurements with a high-gain antenna and knowledge about the properties of the transmit and receive antennas as well as losses along the propagation path. Transmit power measurements for different types of GPS, GLONASS, Galileo, and BeiDou-2 satellites were taken with a 30-m dish antenna of the German Aerospace Center (DLR) located at its ground station in Weilheim. For GPS, total L-band transmit power levels of 50–240 W were obtained, 20–135 W for GLONASS, 95–265 W for Galileo, and 130–185 W for BeiDou-2. The transmit power differs usually only slightly for individual spacecraft within one satellite block. An exception are the GLONASS-M satellites where six subgroups with different transmit power levels could be identified. Considering the antenna thrust in precise orbit determination of GNSS satellites decreases the orbital radius by 1–27 mm depending on the transmit power, the satellite mass, and the orbital period. 相似文献
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针对GNSS定位结果总是存在点位误差,由此导出的长度测量值为点位误差的非线性映射,对于长距离定位量测,其非线性影响较小,线性化近似一般可以满足精度要求,但对于短距离量测,其非线性影响不容忽略的问题。该文探讨了GNSS长度测量不确定性来源,通过单点定位和差分定位试验验证了长度测量不确定性与定位精度、点间距离的关系,测试不同偏差和方差估计公式的适用性。试验表明,对于GNSS高精度、长基线测量,其长度统计偏差可以忽略,且方差为基线向量的方向方差;现有不确定性评估公式在超短基线情形适用性会变差,在这种情形下,试验表明二阶偏差和方差估计更为精确。通过消除长度统计偏差得到无偏估计量,可以有效提高距离量测的可靠性,为提高用户距离量测精度提供有益帮助。 相似文献