共查询到20条相似文献,搜索用时 31 毫秒
1.
Since the beginning of the International Global Navigation Satellite System (GLONASS) Experiment, IGEX, in October 1998,
the Center for Orbit Determination in Europe (CODE) has acted as an analysis center providing precise GLONASS orbits on a
regular basis. In CODE's IGEX routine analysis the Global Positioning System (GPS) orbits and Earth rotation parameters are
introduced as known quantities into the GLONASS processing. A new approach is studied, where data from the IGEX network are
combined with GPS observations from the International GPS Service (IGS) network and all parameters (GPS and GLONASS orbits,
Earth rotation parameters, and site coordinates) are estimated in one processing step. The influence of different solar radiation
pressure parameterizations on the GLONASS orbits is studied using different parameter subsets of the extended CODE orbit model.
Parameterization with three constant terms in the three orthogonal directions, D, Y, and X (D = direction satellite–Sun, Y = direction of the satellite's solar panel axis), and two periodic terms in the X-direction, proves to be adequate for GLONASS satellites. As a result of the processing it is found that the solar radiation
pressure effect for the GLONASS satellites is significantly different in the Y-direction from that for the GPS satellites, and an extensive analysis is carried out to investigate the effect in detail.
SLR observations from the ILRS network are used as an independent check on the quality of the GLONASS orbital solutions. Both
processing aspects, combining the two networks and changing the orbit parameterization, significantly improve the quality
of the determined GLONASS orbits compared to the orbits stemming from CODE's IGEX routine processing.
Received: 10 May 2000 / Accepted: 9 October 2000 相似文献
2.
Sylvain Loyer Félix Perosanz Flavien Mercier Hugues Capdeville Jean-Charles Marty 《Journal of Geodesy》2012,86(11):991-1003
CNES (Centre National d’Etudes Spatiales) and CLS (Collecte Localisation Satellites) became an International GNSS Service (IGS) Analysis Center (AC) the 20th of May 2010. Since 2009, we are using the integer ambiguity fixing at the zero-difference level strategy in our software package (GINS/Dynamo) as an alternative to classical differential approaches. This method played a key role among all the improvements in the GPS processing we made during this period. This paper provides to the users the theoretical background, the strategies and the models used to compute the products (GPS orbits and clocks, weekly station coordinate estimates and Earth orientation parameters) that are submitted weekly to the IGS. The practical realization of the two-step, ambiguity-fixing scheme (wide-lane and narrow-lane) is described in detail. The ambiguity fixing improved our orbit overlaps from 6 to 3?cm WRMS in the tangential and normal directions. Since 2008, our products have been also regularly compared to the IGS final solutions by the IGS Analysis Center Coordinator. The joint effects of ambiguity fixing and dynamical model changes (satellite solar radiation pressure and albedo force) improved the consistency with IGS orbits from 35 to 18?mm 3D-WRMS. Our innovative strategy also gives additional powerful properties to the GPS satellite phase clock solutions. Single receiver (zero-difference) ambiguity resolution becomes possible. An overview of the applications is given. 相似文献
3.
Jânia Duha Germano Bruno Afonso Luiz Danilo Damasceno Ferreira 《Journal of Geodesy》2006,80(12):665-674
Highly precise satellite-derived coordinates depend on accurate orbit predictions, which cannot be achieved with purely empirical models. Global positioning system (GPS) satellites undergo several periodic perturbing forces that have to be modeled and understood. In this scenario, small non-gravitational forces can no longer be neglected when the purpose of the orbital analysis is to obtain accurate results (Vilhena de Moraes 1994). Together with solar radiation pressure, thermal re-emission effects due to solar heating and Earth albedo are the two most important non-gravitational effects. While solar radiation pressure is widely understood, our knowledge about thermal re-emission effects on GPS satellites is in its infancy. Few models have been proposed in recent years and despite the interest of the scientific community, there is a lack of detailed results concerning the magnitude and the behavior of such forces. The aim of this work is to provide a thermal re-emission force model for GPS satellites, simple enough to minimize the problem of modeling a satellite of complex shape with several components on its surface, but accurate enough to provide an estimate of the magnitude and the behavior of these forces, as well as to provide some input to the present knowledge about photon thrust on GPS satellites. Some results of this work point to the fact that thermal re-emission effects are good candidates to partially explain the Y-bias for GPS satellites. 相似文献
4.
由精密星历利用拉格朗日插值公式求二次导数的方法计算了卫星在J2000.0惯性坐标系下的总加速度;利用现有的力模型计算了地球中心引力,地球非球形摄动力,太阳、月球和其他行星的摄动力,地球固体潮摄动力,相对论效应摄动力对GPS/BDS卫星所产生的加速度数值大小;利用G-file里的BERNE太阳光压模型参数计算了GPS卫星太阳光压摄动加速度大小;对GPS/BDS卫星所受的不同摄动力进行了数值分析,对同一摄动力对不同类型卫星的影响进行了数值分析比较。结果表明,现有力模型与GPS/BDS卫星所受的实际作用力仍有一定的差距,不同类型卫星所受摄动力有明显差异,在精密定轨的实际应用中应根据不同类型卫星建立合适的力学模型。 相似文献
5.
The Center for Orbit Determination in Europe (CODE) has been involved in the processing of combined GPS/GLONASS data during the International GLONASS Experiment (IGEX). The resulting precise orbits were analyzed using the program SORBDT. Introducing one satellites positions as pseudo-observations, the program is capable of fitting orbital arcs through these positions using an orbit improvement procedure based on the numerical integration of the satellites orbit and its partial derivative with respect to the orbit parameters. For this study, the program was enhanced to estimate selected parameters of the Earths gravity field. The orbital periods of the GPS satellites are —in contrast to those of the GLONASS satellites – 2:1 commensurable (P
Sid:P
GPS) with the rotation period of the Earth. Therefore, resonance effects of the satellite motion with terms of the geopotential occur and they influence the estimation of these parameters. A sensitivity study of the GPS and GLONASS orbits with respect to the geopotential coefficients reveals that the correlations between different geopotential coefficients and the correlations of geopotential coefficients with other orbit parameters, in particular with solar radiation pressure parameters, are the crucial issues in this context. The estimation of the resonant geopotential terms is, in the case of GPS, hindered by correlations with the simultaneously estimated radiation pressure parameters. In the GLONASS case, arc lengths of several days allow the decorrelation of the two parameter types. The formal errors of the estimates based on the GLONASS orbits are a factor of 5 to 10 smaller for all resonant terms.
AcknowledgmentsThe authors would like to thank all the organizations involved in the IGS and the IGEX campaign, in particular those operating an IGS or IGEX observation site and providing the indispensable data for precise orbit determination. 相似文献
6.
Reducing the draconitic errors in GNSS geodetic products 总被引:2,自引:2,他引:0
C. J. Rodriguez-Solano U. Hugentobler P. Steigenberger M. Bloßfeld M. Fritsche 《Journal of Geodesy》2014,88(6):559-574
Systematic errors at harmonics of the GPS draconitic year have been found in diverse GPS-derived geodetic products like the geocenter $Z$ -component, station coordinates, $Y$ -pole rate and orbits (i.e. orbit overlaps). The GPS draconitic year is the repeat period of the GPS constellation w.r.t. the Sun which is about 351 days. Different error sources have been proposed which could generate these spurious signals at the draconitic harmonics. In this study, we focus on one of these error sources, namely the radiation pressure orbit modeling deficiencies. For this purpose, three GPS+GLONASS solutions of 8 years (2004–2011) were computed which differ only in the solar radiation pressure (SRP) and satellite attitude models. The models employed in the solutions are: (1) the CODE (5-parameter) radiation pressure model widely used within the International GNSS Service community, (2) the adjustable box-wing model for SRP impacting GPS (and GLONASS) satellites, and (3) the adjustable box-wing model upgraded to use non-nominal yaw attitude, specially for satellites in eclipse seasons. When comparing the first solution with the third one we achieved the following in the GNSS geodetic products. Orbits: the draconitic errors in the orbit overlaps are reduced for the GPS satellites in all the harmonics on average 46, 38 and 57 % for the radial, along-track and cross-track components, while for GLONASS satellites they are mainly reduced in the cross-track component by 39 %. Geocenter $Z$ -component: all the odd draconitic harmonics found when the CODE model is used show a very important reduction (almost disappearing with a 92 % average reduction) with the new radiation pressure models. Earth orientation parameters: the draconitic errors are reduced for the $X$ -pole rate and especially for the $Y$ -pole rate by 24 and 50 % respectively. Station coordinates: all the draconitic harmonics (except the 2nd harmonic in the North component) are reduced in the North, East and Height components, with average reductions of 41, 39 and 35 % respectively. This shows, that part of the draconitic errors currently found in GNSS geodetic products are definitely induced by the CODE radiation pressure orbit modeling deficiencies. 相似文献
7.
Ant Sibthorpe Willy Bertiger Shailen D. Desai Bruce Haines Nate Harvey Jan P. Weiss 《Journal of Geodesy》2011,85(8):505-517
The subtle effects of different Global Positioning System (GPS) satellite force models are becoming apparent now that mature
processing strategies are reaching new levels of accuracy and precision. For this paper, we tested several approaches to solar
radiation pressure (SRP) modeling that are commonly used by International GNSS Service (IGS) analysis centers. These include
the GPS Solar Pressure Model (GSPM; Bar-Sever and Kuang in The Interplanetary Network Progress Report 42-160, 2005) and variants of the so-called DYB model (Springer et al. in Adv Space Res 23:673–676, 1999). Our results show that currently observed differences between GPS orbit solutions from the various IGS analysis centers
are in large part explained by differences between their respective approaches to modeling SRP. DYB-based strategies typically
generate orbit solutions that have the smallest differences with respect to the IGS final combined solution, largely because
the DYB approach is most commonly used by the contributing analysis centers. However, various internal and external metrics,
including ambiguity resolution statistics and satellite laser ranging observations, support continued use of the GSPM-based
approach for precise orbit determination of the GPS constellation, at least when using the GIPSY-OASIS software. 相似文献
8.
Zhigui Kang Byron Tapley Srinivas Bettadpur John Ries Peter Nagel Rick Pastor 《Journal of Geodesy》2006,80(6):322-331
The GRACE (gravity recovery and climate experiment) satellites, launched in March 2002, are each equipped with a BlackJack GPS onboard receiver for precise orbit determination and gravity field recovery. Since launch, there have been significant improvements in the background force models used for satellite orbit determination, most notably the model for the geopotential. This has resulted in significant improvements to orbit accuracy for very low altitude satellites. The purpose of this paper is to investigate how well the orbits of the GRACE satellites (about 470 km in altitude) can currently be determined using only GPS data and based on the current models and methods. The orbit accuracy is assessed using a number of tests, which include analysis of orbit fits, orbit overlaps, orbit connecting points, satellite Laser ranging residuals and K-band ranging (KBR) residuals. We show that 1-cm radial orbit accuracy for the GRACE satellites has probably been achieved. These precise GRACE orbits can be used for such purposes as improving gravity recovery from the GRACE KBR data and for atmospheric profiling, and they demonstrate the quality of the background force models being used. 相似文献
9.
Improved antenna phase center models for GLONASS 总被引:6,自引:2,他引:4
Rolf Dach Ralf Schmid Martin Schmitz Daniela Thaller Stefan Schaer Simon Lutz Peter Steigenberger Gerhard Wübbena Gerhard Beutler 《GPS Solutions》2011,15(1):49-65
Thanks to the increasing number of active GLONASS satellites and the increasing number of multi-GNSS tracking stations in
the network of the International GNSS Service (IGS), the quality of the GLONASS orbits has become significantly better over
the last few years. By the end of 2008, the orbit RMS error had reached a level of 3–4 cm. Nevertheless, the strategy to process
GLONASS observations still has deficiencies: one simplification, as applied within the IGS today, is the use of phase center
models for receiver antennas for the GLONASS observations, which were derived from GPS measurements only, by ignoring the
different frequency range. Geo++ GmbH calibrates GNSS receiver antennas using a robot in the field. This procedure yields
now separate corrections for the receiver antenna phase centers for each navigation satellite system, provided its constellation
is sufficiently populated. With a limited set of GLONASS calibrations, it is possible to assess the impact of GNSS-specific
receiver antenna corrections that are ignored within the IGS so far. The antenna phase center model for the GLONASS satellites
was derived in early 2006, when the multi-GNSS tracking network of the IGS was much sparser than it is today. Furthermore,
many satellites of the constellation at that time have in the meantime been replaced by the latest generation of GLONASS-M
satellites. For that reason, this paper also provides an update and extension of the presently used correction tables for
the GLONASS satellite antenna phase centers for the current constellation of GLONASS satellites. The updated GLONASS antenna
phase center model helps to improve the orbit quality. 相似文献
10.
Is the long-term variation of the estimated GPS differential code biases associated with ionospheric variability? 总被引:1,自引:0,他引:1
The global positioning system (GPS) differential code biases (DCB) provided by the International GNSS Service (IGS) show solar-cycle-like variation during 2002–2013. This study is to examine whether this variation of the GPS DCBs is associated with ionospheric variability. The GPS observations from low earth orbit (LEO) satellites including CHAMP, GRACE and Jason-1 are used to address this issue. The GPS DCBs estimated from the LEO-based observations at different orbit altitudes show a similar tendency as the IGS DCBs. However, this solar-cycle-like dependency is eliminated when the DCBs of 13 continuously operating GPS satellites are constrained to zero-mean. Our results thus revealed that ionospheric variation is not responsible for the long-term variation of the GPS DCBs. Instead, it is attributed to the GPS satellite replacement with different satellite types and the zero-mean condition imposed on all satellite DCBs. 相似文献
11.
利用全球约110个国际GNSS服务(International GNSS Service,IGS)测站2013年全年观测数据,分析和研究了GPS和全球卫星导航系统(global navigation satellite system,GLONASS)卫星偏航姿态对其精密轨道和钟差的影响。结果表明,偏航姿态对不同型号GPS卫星轨道和钟差的影响程度不同,当采用偏航姿态改正后地影期的BLOCK ⅡA型卫星轨道改善可达17 mm,BLOCK ⅡF为近5 mm,而BLOCK ⅡR几乎不受影响。由于偏航姿态对GLONASS-M卫星定轨精度影响较大,因此,当改正偏航姿态后所有GLONASS卫星相对于IGS最终轨道平均一维差异提高10 mm,相对于德国地学中心(German Research Center for Geosciences,GFZ)最终钟差平均标准差提升0.034 ns。 相似文献
12.
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
13.
14.
A Discussion of IGS Solutions and Their Impact on Geodetic and Geophysical Applications 总被引:1,自引:0,他引:1
The International Association of Geodesy officially established the International GPS Service (IGS) on Janaury 1, 1994. Its
prime objective is to provide support and a rerefence system for a wide variety of scientific and practical applications involving
GPS. To fulfill its role the IGS also generates, in addition to its fundamental products (orbital/staion positions and consistent
Earth orientation parameters), additional reference-system products providing the necessary infrastructure, standards, and
means of calibrations for timing and various atmospheric applications of GPS. The generation and efficient application of
IGS products and their impact on a number of positioning and atmospheric applications, including low earth orbit satellites,
is reviewed and discussed. @ 1998 John Wiley & Sons, Inc. 相似文献
15.
重力恢复和气候实验(gravity recovery and climate experiment,GRACE)任务受限于卫星的低轨极地轨道性质和编队模式,确定的重力场模型C20项存在不足。与之相比,全球定位系统(global positioning system,GPS)卫星为倾斜轨道,卫星数量多,将GPS卫星的精密轨道数据作为伪观测值,使用动力学方法进行C20项确定的可行性研究。结果显示,2017年C20项时间序列的平均值比GRACE更接近卫星激光测距(satellite laser ranging,SLR)的结果,且不存在明显的约160 d的周期信号,表明利用GPS卫星解算C20项具有可行性。同时估计了光压模型P1参数,与GAMIT软件解算结果接近,进一步验证C20项解算结果的可靠性。 相似文献
16.
Impact of Earth radiation pressure on GPS position estimates 总被引:10,自引:8,他引:2
C. J. Rodriguez-Solano U. Hugentobler P. Steigenberger S. Lutz 《Journal of Geodesy》2012,86(5):309-317
GPS satellite orbits available from the International GNSS Service (IGS) show a consistent radial bias of up to several cm
and a particular pattern in the Satellite Laser Ranging (SLR) residuals, which are suggested to be related to radiation pressure
mismodeling. In addition, orbit-related frequencies were identified in geodetic time series such as apparent geocenter motion
and station displacements derived from GPS tracking data. A potential solution to these discrepancies is the inclusion of
Earth radiation pressure (visible and infrared) modeling in the orbit determination process. This is currently not yet considered
by all analysis centers contributing to the IGS final orbits. The acceleration, accounting for Earth radiation and satellite
models, is introduced in this paper in the computation of a global GPS network (around 200 IGS sites) adopting the analysis
strategies from the Center for Orbit Determination in Europe (CODE). Two solutions covering 9 years (2000–2008) with and without
Earth radiation pressure were computed and form the basis for this study. In previous studies, it has been shown that Earth
radiation pressure has a non-negligible effect on the GPS orbits, mainly in the radial component. In this paper, the effect
on the along-track and cross-track components is studied in more detail. Also in this paper, it is shown that Earth radiation
pressure leads to a change in the estimates of GPS ground station positions, which is systematic over large regions of the
Earth. This observed “deformation” of the Earth is towards North–South and with large scale patterns that repeat six times
per GPS draconitic year (350 days), reaching a magnitude of up to 1 mm. The impact of Earth radiation pressure on the geocenter
and length of day estimates was also investigated, but the effect is found to be less significant as compared to the orbits
and position estimates. 相似文献
17.
以ECOM经验光压模型为基础,利用北斗卫星3年的精密星历进行轨道拟合,获得了ECOM光压参数的变化规律,给出了北斗3类卫星的ECOM光压参数选择策略。从北斗卫星姿态控制模式出发,通过卫星星体受照分析,指出在北斗卫星地影期零偏航状态下,由于太阳对卫星帆板的不正照,导致与动态偏航姿态相比,光压摄动力存在与轨道周期相关的分量,需要在ECOM 5参数的基础上增加D向周期分量进行吸收。通过MGEX全球网数据定轨试验,本文提出的方法可使零偏段定轨重叠段位置精度提高50%~80%。 相似文献
18.
王解先 《地球空间信息科学学报》2009,12(2):95-99
Orbit fitting is used in many GPS applications. For example, in Precise Point Positioning (PPP), GPS orbits (SP3 orbits) are normally retrieved either from IGS or from one of its Analysis Centers (ACs) with 15 minutes’ sampling, which is much bigger than the normal observation sampling. Therefore, algorithms should be derived to fit GPS orbits to the observation time. Many methods based on interpolation were developed. Using these methods the orbits fit well at the sampling points. However, these methods ig... 相似文献
19.
非保守力模型精度不高是制约BDS-3卫星定轨精度的主要因素之一。本文针对BDS-3 MEO卫星构建了地球辐射、天线辐射和箱体-两翼(BW)太阳光压模型,对典型的经验光压模型(ECOM1和ECOM2)进行补偿得到多个非保守力模型,收集全球观测网的数据进行定轨试验,通过轨道重叠互差和激光测距残差分析比较不同轨道模型的优劣。试验结果表明,经验光压模型是影响轨道精度的主要因素,在名义偏航模式下,ECOM2具有更好的表现,但ECOM1对卫星的姿态模式更不敏感。地球辐射和天线辐射会引起北斗卫星轨道径向约3 cm的系统性偏差,对二者建模后,几乎可以完全消除卫星C29和C30的激光残差系统偏差,但卫星C20和C21的系统偏差反而增大。此外,增加box-wing模型对于提高轨道精度也是有益的。 相似文献
20.
Chinese BeiDou navigation satellite system is in official service as a regional constellation with five geostationary earth orbit (GEO) satellites, five inclined geosynchronous satellite orbit (IGSO) satellites and four medium earth orbit (MEO) satellites. There are mainly two methods for precise orbit determination of the BeiDou constellation found in the current literatures. One is the independent single-system method, where only BeiDou observations are used without help from other GNSS systems. The other is the two-step GPS-assisted method where in the first step, GPS data are used to resolve some common parameters, such as station coordinates, receiver clocks and zenith tropospheric delay parameters, which are then introduced as known quantities in BeiDou processing in the second step. We conduct a thorough performance comparison between the two methods. Observations from the BeiDou experimental tracking stations and the IGS Multi-GNSS Experiment network from January 1 to March 31, 2013, are processed with the Positioning and Navigation Data Analyst (PANDA) software. The results show that for BeiDou IGSO and MEO satellites, the two-step GPS-assisted method outperforms the independent single-system method in both internal orbit overlap precision and external satellite laser ranging validation. For BeiDou GEO satellites, the two methods show close performances. Zenith tropospheric delays estimated from the first method are very close to those estimated from GPS precise point positioning in the second method, with differences of several millimeters. Satellite clock estimates from the two methods show similar performances when assessing the stability of the BeiDou on board clocks. 相似文献