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1.
Krzysztof Sośnica Lars Prange Kamil Kaźmierski Grzegorz Bury Mateusz Drożdżewski Radosław Zajdel Tomasz Hadas 《Journal of Geodesy》2018,92(2):131-148
The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR–GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0–2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal \(-44.9, -35.0\), and \(-22.4\) mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear and angular velocities. 相似文献
2.
Orbit and clock analysis of Compass GEO and IGSO satellites 总被引：11，自引：5，他引：6
China is currently focussing on the establishment of its own global navigation satellite system called Compass or BeiDou. At present, the Compass constellation provides four usable satellites in geostationary Earth orbit (GEO) and five satellites in inclined geosynchronous orbit (IGSO). Based on a network of six Compass-capable receivers, orbit and clock parameters of these satellites were determined. The orbit consistency is on the 1–2 dm level for the IGSO satellites and on the several decimeter level for the GEO satellites. These values could be confirmed by an independent validation with satellite laser ranging. All Compass clocks show a similar performance but have a slightly lower stability compared to Galileo and the latest generation of GPS satellites. A Compass-only precise point positioning based on the products derived from the six-receiver network provides an accuracy of several centimeters compared to the GPS-only results. 相似文献
3.
Initial results of centralized autonomous orbit determination of the new-generation BDS satellites with inter-satellite link measurements 总被引：3，自引：0，他引：3
Chengpan Tang Xiaogong Hu Shanshi Zhou Li Liu Junyang Pan Liucheng Chen Rui Guo Lingfeng Zhu Guangming Hu Xiaojie Li Feng He Zhiqiao Chang 《Journal of Geodesy》2018,92(10):1155-1169
Autonomous orbit determination is the ability of navigation satellites to estimate the orbit parameters on-board using inter-satellite link (ISL) measurements. This study mainly focuses on data processing of the ISL measurements as a new measurement type and its application on the centralized autonomous orbit determination of the new-generation Beidou navigation satellite system satellites for the first time. The ISL measurements are dual one-way measurements that follow a time division multiple access (TDMA) structure. The ranging error of the ISL measurements is less than 0.25 ns. This paper proposes a derivation approach to the satellite clock offsets and the geometric distances from TDMA dual one-way measurements without a loss of accuracy. The derived clock offsets are used for time synchronization, and the derived geometry distances are used for autonomous orbit determination. The clock offsets from the ISL measurements are consistent with the L-band two-way satellite, and time–frequency transfer clock measurements and the detrended residuals vary within 0.5 ns. The centralized autonomous orbit determination is conducted in a batch mode on a ground-capable server for the feasibility study. Constant hardware delays are present in the geometric distances and become the largest source of error in the autonomous orbit determination. Therefore, the hardware delays are estimated simultaneously with the satellite orbits. To avoid uncertainties in the constellation orientation, a ground anchor station that “observes” the satellites with on-board ISL payloads is introduced into the orbit determination. The root-mean-square values of orbit determination residuals are within 10.0 cm, and the standard deviation of the estimated ISL hardware delays is within 0.2 ns. The accuracy of the autonomous orbits is evaluated by analysis of overlap comparison and the satellite laser ranging (SLR) residuals and is compared with the accuracy of the L-band orbits. The results indicate that the radial overlap differences between the autonomous orbits are less than 15.0 cm for the inclined geosynchronous orbit (IGSO) satellites and less than 10.0 cm for the MEO satellites. The SLR residuals are approximately 15.0 cm for the IGSO satellites and approximately 10.0 cm for the MEO satellites, representing an improvement over the L-band orbits. 相似文献
4.
为了对多个全球导航卫星系统（global navigation satellite system, GNSS）当前的广播星历精度进行一个全面的分析,对比了2014—2018年共5 a的GNSS广播星历与精密星历,并对全球定位系统（global positioning system, GPS）、格洛纳斯卫星导航系统（global navigation satellite system, GLONASS）、伽利略卫星导航系统（Galileo satellite navigation system, Galileo）、北斗卫星导航系统（BeiDou navigation satellite system, BDS）、准天顶卫星系统（quasi-zenith satellite system, QZSS）等5个系统的广播星历长期精度变化进行了分析。结果表明:5 a中GPS的广播星历轨道及钟差精度最稳定;GLONASS的广播星历轨道精度稳定性较好,但其钟差精度存在较大的离散度;Galileo得益于具备全面运行能力（full operational capability, FOC）卫星的大量发射及运行,其广播星历轨道、钟差精度大幅度变好,切向轨道、法向轨道与钟差精度已赶超GPS;BDS的广播星历轨道精度离散度较大,钟差精度出现不稳定现象;QZSS的广播星历轨道与钟差精度的稳定性与离散度相对最差。以2018年1 a的广播星历与精密星历为例分析了各个系统当前的广播星历精度,结果表明,当前GPS、GLONASS、Galileo、BDS、QZSS的考虑轨道误差与钟差误差贡献的空间信号测距误差（signal-in-space ranging error,SISRE）分别为0.806 m、2.704 m、0.320 m、1.457 m、1.645 m,表明Galileo广播星历整体精度最高,GPS次之,其次分别是BDS、QZSS和GLONASS。只考虑轨道误差贡献的SISRE分别为0.167 m、0.541 m、0.229 m、0.804 m、0.675 m,表明GPS广播星历轨道精度最高,其次分别是Galileo、GLONASS、QZSS和BDS。GPS卫星广播星历中新型号卫星的钟差精度总体要优于旧型号卫星。 相似文献
5.
6.
Weixing Zhang Yidong Lou Shengfeng Gu Chuang Shi Jennifer S. Haase Jingnan Liu 《GPS Solutions》2016,20(4):665-676
We present the joint estimation model for Global Positioning System/BeiDou Navigation Satellite System (GPS/BDS) real-time clocks and present the initial satellite clock solutions determined from 106 stations of the international GNSS service multi-GNSS experiment and the BeiDou experimental tracking stations networks for 1 month in December, 2012. The model is shown to be efficient enough to have no practical computational limit for producing 1-Hz clock updates for real-time applications. The estimated clocks were assessed through the comparison with final clock products and the analysis of post-fit residuals. Using the estimated clocks and corresponding orbit products (GPS ultra-rapid-predicted and BDS final orbits), the root-mean-square (RMS) values of coordinate differences from ground truth values are around 1 and 2–3 cm for GPS-only and BDS-only daily mean static precise point positioning (PPP) solutions, respectively. Accuracy of GPS/BDS combined static PPP solutions falls in between that of GPS-only and BDS-only PPP results, with RMS values approximately 1–2 cm in all three components. For static sites, processed in the kinematic PPP mode, the daily RMS values are normally within 4 and 6 cm after convergence for GPS-only and BDS-only results, respectively. In contrast, the combined GPS/BDS kinematic PPP solutions show higher accuracy and shorter convergence time. Additionally, the BDS-only kinematic PPP solutions using clock products derived from the proposed joint estimation model were superior compared to those computed using the single-system estimation model. 相似文献
7.
北斗三号卫星之间及卫星与锚固站之间在Ka频段的伪距测量为其提供了一种不依赖于地面监测站的独立定轨和时间同步能力。本文针对星间链路分时测量的特点,采用分段一次多项式对卫星钟差进行建模,直接利用原始的星地和星间单程Ka伪距实现一体化定轨和时间同步并同时解算锚固站设备硬件时延。利用北斗三号8颗卫星和2个锚固站的实测Ka伪距数据进行验证,结果表明:在利用导航电文的预报钟速信息进行修正的情况下,星间Ka伪距残差RMS为0.052 m;R方向卫星轨道确定和预报精度(RMS)分别为0.016、0.033 m;卫星钟差估计和预报精度(95%)分别为0.038、0.992 ns;解算得到的锚固站收发设备时延之和的稳定性优于0.5 ns。试验还展示了该方法的适应能力:在没有预报钟速信息的极端情况下,虽然星间Ka伪距残差RMS增大了242%,但R方向轨道确定和预报精度仍分别达到0.021、0.041 m,钟差估计和预报精度分别达到0.040、1.092 ns。 相似文献
8.
Maintaining real-time precise point positioning during outages of orbit and clock corrections 总被引：1，自引：1，他引：0
The precise point positioning (PPP) is a popular positioning technique that is dependent on the use of precise orbits and clock corrections. One serious problem for real-time PPP applications such as natural hazard early warning systems and hydrographic surveying is when a sudden communication break takes place resulting in a discontinuity in receiving these orbit and clock corrections for a period that may extend from a few minutes to hours. A method is presented to maintain real-time PPP with 3D accuracy less than a decimeter when such a break takes place. We focus on the open-access International GNSS Service (IGS) real-time service (RTS) products and propose predicting the precise orbit and clock corrections as time series. For a short corrections outage of a few minutes, we predict the IGS-RTS orbits using a high-order polynomial, and for longer outages up to 3 h, the most recent IGS ultra-rapid orbits are used. The IGS-RTS clock corrections are predicted using a second-order polynomial and sinusoidal terms. The model parameters are estimated sequentially using a sliding time window such that they are available when needed. The prediction model of the clock correction is built based on the analysis of their properties, including their temporal behavior and stability. Evaluation of the proposed method in static and kinematic testing shows that positioning precision of less than 10 cm can be maintained for up to 2 h after the break. When PPP re-initialization is needed during the break, the solution convergence time increases; however, positioning precision remains less than a decimeter after convergence. 相似文献
9.
CODE’s five-system orbit and clock solution—the challenges of multi-GNSS data analysis 总被引：1，自引：1，他引：0
Lars Prange Etienne Orliac Rolf Dach Daniel Arnold Gerhard Beutler Stefan Schaer Adrian Jäggi 《Journal of Geodesy》2017,91(4):345-360
This article describes the processing strategy and the validation results of CODE’s MGEX (COM) orbit and satellite clock solution, including the satellite systems GPS, GLONASS, Galileo, BeiDou, and QZSS. The validation with orbit misclosures and SLR residuals shows that the orbits of the new systems Galileo, BeiDou, and QZSS are affected by modelling deficiencies with impact on the orbit scale (e.g., antenna calibration, Earth albedo, and transmitter antenna thrust). Another weakness is the attitude and solar radiation pressure (SRP) modelling of satellites moving in the orbit normal mode—which is not yet correctly considered in the COM solution. Due to these issues, we consider the current state COM solution as preliminary. We, however, use the long-time series of COM products for identifying the challenges and for the assessment of model-improvements. The latter is demonstrated on the example of the solar radiation pressure (SRP) model, which has been replaced by a more generalized model. The SLR validation shows that the new SRP model significantly improves the orbit determination of Galileo and QZSS satellites at times when the satellite’s attitude is maintained by yaw-steering. The impact of this orbit improvement is also visible in the estimated satellite clocks—demonstrating the potential use of the new generation satellite clocks for orbit validation. Finally, we point out further challenges and open issues affecting multi-GNSS data processing that deserves dedicated studies. 相似文献
10.
The products of Wuhan University with 5-min sampling are used to analyze the characteristics of BeiDou satellite clocks. Two nanoseconds root-mean-square (RMS) variations are obtained for 1-day quadratic fits in the sub-daily region. The relativistic effects of BDS clocks are also studied. General relativity predicts that linear variation of the semimajor axes of geostationary and inclined geosynchronous satellites causes a quadratic clock drift with a magnitude at the 10?16/day level. The observed drift is higher than what general relativity theory would produce. Several periodic terms are found in the satellite clock variations through spectrum analysis. In order to identify the origin of the BDS clock harmonics, a correlation analysis between the period or amplitude of the harmonics and properties of the satellite orbits is performed. It is found that the period of the harmonics is not exactly equal to the orbit period, but rather the ratio of the orbit period to clock period is almost the same as that of a sidereal day to solar day. The BDS clocks obey white frequency noise statistics for intervals from 300 s to several thousands seconds. For intervals greater than 10,000 s, all the BDS satellites display more complex, non-power-law behavior due to the effects of periodic clock variations. 相似文献
11.
针对北斗卫星导航系统的卫星姿态模型、天线相位中心改正及卫星定轨数据处理策略未统一的现状,该文对比分析了武汉大学和德国地学研究中心提供的北斗事后精密轨道和钟差产品的差异及精度,结合实测数据,通过分析精密单点定位的定位精度来比较两中心精密轨道和钟差的差异。实验结果表明:北斗卫星的精密轨道精度与轨道类型有关,地球静止轨道(GEO)卫星的轨道精度为米级,倾斜地球同步轨道(IGSO)卫星的轨道精度为分米级,中地球轨道(MEO)卫星切向、法向和径向的精度分别为10.81、5.41和3.37cm;GEO卫星钟差精度优于0.38ns,IGSO卫星钟差优于0.25ns,MEO卫星钟差优于0.15ns;两家分析中心产品的北斗静态精密单点定位的平面精度相当;北斗静态精密单点定位的RMS统计值平面精度优于3cm,三维精度优于7cm。 相似文献
12.
This paper is aimed at investigating the stability of point positions over time in support of applications that require high
position stability when differential GPS is not feasible. One such application is the use of a P3-Orion aircraft offshore
for magnetic measurement in support of submarine detection. Temporal changes in several GPS errors lead to variability in
the computed positions, so it is not the absolute errors, but rather their temporal variations that are of importance. Furthermore,
the temporal variability of the different error sources may dictate a certain algorithm approach and processing strategy.
This paper analyzes the temporal variations of the broadcast satellite clock model and orbit parameters, as well as ionospheric
errors, because these will typically be the dominant errors for real-time point positioning. These three errors are analyzed
independently. A tropospheric correction is applied when computing all of the position results, so the tropospheric error
itself is not investigated. Satellite clock and orbit errors are analyzed by comparing broadcast and precise post-mission
SV clock corrections and orbits. For the ionosphere, the effect is separated using dual-frequency data. The analysis comprises
primarily of assessing error behaviors and magnitudes through time and frequency analyses. In this way, the differences in
variability of the errors are easily determined. The effect of each error in the position domain is also investigated in addition
to the combined effect. Results show that, on a typical day when single frequency data are processed with broadcast orbit
and clock data, the root mean square (RMS) of the changes in the position errors over a 50-s interval is about 5.8 cm in northing,
4.0 in easting, and 11.0 cm in height. When using precise orbits and clocks, in addition to dual frequency data, these values
improve by 46–56% to 2.7 cm in northing, 2.2 cm in easting, and 4.9 cm in height. Under severe ionospheric activity, the RMS
of the errors decrease from 8.1 to 3.3 cm in northing, 5.7 to 2.6 cm in easting, and 17.0 to 4.9 cm in height, which are improvements
of 54–71%.
Electronic Publication 相似文献
13.
星蚀期北斗卫星轨道性能分析——SLR检核结果 总被引：1，自引：0，他引：1
星蚀期北斗卫星的轨道性能是北斗卫星导航系统性能分析的重要部分。了解北斗卫星导航系统星历中星蚀期轨道的精度,不仅可为系统服务性能评估提供支持,还有助于了解星蚀期精密定轨中相关模型可能存在的问题,进而为精密定轨函数模型改进提供参考。本文基于2014年1月至2015年7月的卫星激光测距资料,重点分析了星蚀期对北斗不同类型卫星轨道的影响,同时也对北斗广播星历和精密星历中整体轨道径向精度进行检核。结果表明:星蚀期内(尤其是偏航机动期间),IGSO/MEO卫星的广播星历和精密星历轨道均存在明显的精度下降;广播星历轨道径向误差达1.5~2.0m,精密星历轨道径向误差超过10.0cm。但仅从轨道径向残差序列中难以发现星蚀期对GEO卫星轨道是否有显著影响。非星蚀期间,IGSO/MEO卫星和GEO卫星的广播星历轨道径向精度分别优于0.5 m和0.9 m。IGSO/MEO卫星的精密星历轨道径向精度优于10.0cm,GEO卫星的轨道径向精度约50.0cm,且存在40.0cm左右的系统性偏差。 相似文献
14.
Xin Li Xingxing Li Gege Liu Guolong Feng Fei Guo Yongqiang Yuan Keke Zhang 《GPS Solutions》2018,22(4):123
GPS precise point positioning (PPP) ambiguity resolution (AR) can improve the positioning accuracy and shorten the convergence time. However, for the BeiDou Satellite Navigation System (BDS), the problems of satellite-induced code bias, imperfections in the error models and the inadequate accuracy of orbit products limit the applications of the BDS PPP AR system, which requires more than 6 h to achieve the first ambiguity-fixed solution. In this study, the accuracy of a wide-lane (WL) uncalibrated phase delay (UPD) is improved after careful consideration of the code bias and multipath. Meanwhile, the accuracy of the BDS float ambiguity is also improved by multi-GNSS fusion and improved precise orbit and clock products, which are critical for high-quality narrow-lane (NL) UPD estimations. With three tracking networks of different scales, including Hong Kong, the Crustal Movement Observation Network of China (CMONOC) and the multi-GNSS experiment (MGEX) networks, the spatial–temporal characteristics of WL and NL UPDs for BDS GEO/IGSO/MEO satellites are analyzed, and the PPP AR is performed. Numerous results show that WL and NL UPDs with a standard deviation (STD) of less than 0.15 cycles can be achieved for BDS GEO satellites, while a STD of less than 0.1 cycles can be obtained for IGSO and MEO satellites. With the precise UPD estimation, for the first time, the BDS PPP rapid ambiguity resolution for GEO/IGSO/MEO satellites is achieved. We found that the average time to first fix (TTFF) of the BDS PPP AR is shortened significantly, to approximately 40 min for Hong Kong and the CMONOC, while the TTFF was 57.4 min for the MGEX networks. With ambiguity resolution, the accuracy of the daily BDS PPP in the east, north and vertical directions improves from 1.74 cm, 1.08 cm, and 5.52 cm to 0.72 cm, 0.54 cm, and 3.21 cm for the Hong Kong network, 2.24 cm, 2.31 cm, and 5.64 cm to 1.18 cm, 0.79 cm, and 3.30 cm for the CMONOC, and 2.71 cm, 1.80 cm, and 6.00 cm to 1.58 cm, 1.15 cm, and 4.33 cm for the MGEX networks. Significant improvement is also achieved for kinematic PPP, with improvements of 40.41%, 34.33% and 37.17% in the east, north and vertical directions for the MGEX networks, respectively. 相似文献
15.
GNSS是实时定位导航最重要的方法,精密卫星轨道钟差产品是GNSS高精度服务的前提。国际GNSS服务中心(IGS)及其分析中心长期致力于GNSS数据处理的研究及高精度轨道和钟差产品的提供。GFZ作为分析中心之一,提供GBM多系统快速产品。本文基于2015—2021年GBM提供的精密轨道产品,阐述了数据处理策略,分析了轨道的精度,介绍了非差模糊度固定的原理和对精密定轨的影响。结果表明:GBM快速产品中的GPS轨道精度与IGS后处理精密轨道相比的精度约为11~13 mm,轨道6 h预报精度约为6 cm;GLONASS预报精度约为12 cm,Galileo在该时期的精度均值为10 cm,但是在2016年底以后精度提升到5 cm左右;北斗系统的中轨卫星(medium earth orbit,MEO)在2020年以后预报精度约为10 cm;北斗的静止轨道卫星(geostationary earth orbit,GEO)卫星和QZSS卫星的预报精度在米级;卫星激光测距检核表明,Galileo、GLONASS、BDS-3 MEO卫星轨道精度分别为23、41、47 mm;此外,采用150 d观测值的试验结果表明,采用非差模糊度固定能显著改善MEO卫星轨道精度,对GPS、GLONASS、Galileo、BDS-2和BDS-3的MEO卫星的6 h时预报精度改善率分别为9%~15%、15%~18%、11%~13%、6%~17%和14%~25%。 相似文献
16.
17.
国际GNSS服务(IGS)提供的GPS综合产品被广泛应用于各种高精度科学研究中. 随着各国卫星导航系统的发展,亟需研究针对多系统全球卫星导航系统(GNSS)产品的综合策略. 由于卫星姿态与钟差相互耦合,综合钟差时额外考虑姿态改正将进一步提高综合产品精度,因此研究了一种顾及卫星姿态的GNSS钟差综合策略,改正姿态后GPS综合残差最大可减小80%. 对142个IGS测站进行精密单点定位(PPP)解算发现,综合产品比单个分析中心产品更加稳定,东(E)、北(N)、高(U)方向的动态定位精度最大可提升22.7%、16.7%和18.3%. 相对于未顾及姿态改正的综合产品,顾及姿态改正的综合产品的动态定位精度最大可提升65.3%. 相似文献
18.
Initial results of precise orbit and clock determination for COMPASS navigation satellite system 总被引：8，自引：3，他引：5
Qile Zhao Jing Guo Min Li Lizhong Qu Zhigang Hu Chuang Shi Jingnan Liu 《Journal of Geodesy》2013,87(5):475-486
The development of the COMPASS satellite system is introduced, and the regional tracking network and data availability are described. The precise orbit determination strategy of COMPASS satellites is presented. Data of June 2012 are processed. The obtained orbits are evaluated by analysis of post-fit residuals, orbit overlap comparison and SLR (satellite laser ranging) validation. The RMS (root mean square) values of post-fit residuals for one month’s data are smaller than 2.0 cm for ionosphere-free phase measurements and 2.6 m for ionosphere-free code observations. The 48-h orbit overlap comparison shows that the RMS values of differences in the radial component are much smaller than 10 cm and those of the cross-track component are smaller than 20 cm. The SLR validation shows that the overall RMS of observed minus computed residuals is 68.5 cm for G01 and 10.8 cm for I03. The static and kinematic PPP solutions are produced to further evaluate the accuracy of COMPASS orbit and clock products. The static daily COMPASS PPP solutions achieve an accuracy of better than 1 cm in horizontal and 3 cm in vertical. The accuracy of the COMPASS kinematic PPP solutions is within 1–2 cm in the horizontal and 4–7 cm in the vertical. In addition, we find that the COMPASS kinematic solutions are generally better than the GPS ones for the selected location. Furthermore, the COMPASS/GPS combinations significantly improve the accuracy of GPS only PPP solutions. The RMS values are basically smaller than 1 cm in the horizontal components and 3–4 cm in the vertical component. 相似文献
19.
Yongchang Chen Yunbin Yuan Baocheng Zhang Teng Liu Wenwu Ding Qingsong Ai 《GPS Solutions》2018,22(3):72
A modified mixed-differenced approach for estimating multi-GNSS real-time clock offsets is presented. This approach, as compared to the earlier presented mixed-differenced approach which uses epoch-differenced and undifferenced observations, further adds a satellite-differenced process. The proposed approach, based on real-time orbit products and a mix of epoch-differenced and satellite-differenced observations to estimate only satellite clock offsets and tropospheric zenith wet delays, has fewer estimated parameters than other approaches, and thus its implementing procedure is efficient and can be performed and extended easily. To obtain high accuracy, the approach involves three steps. First, the high-accuracy tropospheric zenith wet delay of each station is estimated using mixed-differenced carrier phase observations. Second, satellite clock offset changes between adjacent epochs are estimated using also mixed-differenced carrier phase observations. Third, the satellite clock offsets at the initial epoch are estimated using satellite-differenced pseudorange observations. Finally, the initial epoch clock results and clock offset changes are concatenated to obtain the clock results of the current epoch. To validate the real-time satellite clock results, multi-GNSS post-processing clock products from IGS ACs were selected for comparison. From the comparison, the standard deviations of the GPS, GLONASS, BeiDou and Galileo systems clock results are approximately 0.1–0.4 ns, except for the BeiDou GEO satellites. The root mean squares are about 0.4–2.3 ns, which are similar to those of other international real-time products. When the clock estimates were assessed based on a pseudo-kinematic PPP procedure, the positioning accuracies in the East, North and Up components reach 5.6, 5.5 and 7.6 cm, respectively, which meet the centimeter level and are comparable to the application of other products. 相似文献
20.
BDS/GPS精密单点定位收敛时间与定位精度的比较 总被引：5，自引：1，他引：4
采用武汉大学卫星导航定位技术研究中心发布的北斗精密卫星轨道和钟差,在TriP 2.0软件的基础上实现了BDS PPP定位算法,并利用大量实测数据进行了BDS/GPS静态PPP和动态PPP浮点解试验。结果表明,BDS静态PPP的收敛时间约为80min,动态PPP的收敛时间为100min;对于3h的观测数据,静态PPP收敛后定位精度优于5cm,动态PPP收敛后水平方向优于8cm,高程方向约12cm;与GPS PPP类似,东分量上定位精度较北分量稍差。当前由于BDS的全球跟踪站有限,精密轨道和钟差精度不如GPS,因此BDS PPP的收敛时间较GPS长,但收敛后可实现厘米至分米级的绝对定位。 相似文献