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1.
当GPS、GALILEO卫星运行至与太阳、地球近似共线时,卫星很难维持名义姿态,将出现一段时间的偏航姿态异常。本文基于不同分析中心所提供的精密轨道和钟差产品,在卫星偏航姿态异常时期,设计不同姿态改正策略,选取全球分布的7个MGEX站10 d实测数据,分析了GPS、GALILEO卫星的天线相位中心改正、相位缠绕改正对观测值残差及动态PPP定位结果的影响。研究表明,在卫星偏航姿态异常时期,采用名义偏航姿态对GPS、GALILEO卫星观测值残差的影响可分别达到8和11 cm,在此期间,GPS/GALILEO卫星采用模型偏航姿态,与采用名义偏航姿态相比,动态PPP的E、N、U 3个方向的定位精度可分别提高13.30%、15.77%和12.98%,相较于剔除卫星策略,采用模型偏航姿态的动态PPP定位精度在E、N、U方向可分别提高5.399%、4.430%、5.992%。 相似文献
2.
在精密单点定位中,相位缠绕是一项不可忽略的误差。相位缠绕的计算严格依赖于卫星姿态的确立,不同的卫星类型产生不同的异常。本文给出了卫星在正常情况下的姿态模型和在异常情况下的姿态改正模型。使用真实数据测试以验证本文所提出模型的正确性。观察滤波收敛后出现异常情况的卫星观测值的残差,结果表明:在异常时期残差最大可能超过20 cm,然而使用本文的改正模型,残差可降低到5 cm以下。使用不同分析中心的精密轨道和钟差产品,效果存在微小差异。II/IIA卫星通过地影区域的时间最长可达1 h,此期间卫星姿态完全受航向角偏差(II/IIA为+0.5°)控制,出了地影区域后30 min,姿态难以模型化,因此这30 min的观测数据不建议采用。 相似文献
3.
A simplified yaw-attitude model for eclipsing GPS satellites 总被引：11，自引：2，他引：9
J. Kouba 《GPS Solutions》2009,13(1):1-12
A simplified yaw-attitude modeling, consistent with Bar-Sever (1996), has been implemented and tested in the NRCan PPP software.
For Block IIR GPS satellite it is possible to model yaw-attitude control during eclipsing periods by using the constant hardware
yaw rate of 0.20°/s. The Block IIR satellites maintain the nominal yaw attitude even during a shadow crossing (Y. E. Bar-Sever,
private communication, 2007), except for the noon and shadow midnight turn maneuvers, both of which can be modeled and last
up to 15 min. Thus, for Block IIR satellites it is possible to maintain continuous satellite clock estimation even during
eclipsing periods. For the Block II/IIA satellites, it is possible to model satisfactorily the noon turns and also shadow
crossing, thanks to the permanent positive yaw bias of 0.5°, implemented in November 1995. However, in order to model the
Block II/IIA shadow crossings, satellite specific yaw rates should be used, either solved for or averaged yaw-rate solutions.
These yaw rates as estimated by the Jet Propulsion Laboratory (JPL) can differ significantly from the nominal hardware values.
The Block II/IIA post-shadow recovery periods, which last about 30 min, should be considered uncertain and cannot be properly
modeled. Data from post-shadow recovery periods should, therefore, not be used in precise global GPS analyses (Bar-Sever 1996). For high-precision applications, it is essential that users implement a yaw-attitude model, which is consistent with the
generation of the satellite clocks. Initial testing and analyses, based on the IGS and AC Final orbits and clocks have revealed
that during eclipsing periods, significant inconsistencies in yaw-attitude modeling still exist amongst the IGS Analyses Centers,
which contribute to the errors of the IGS Final clock combinations. 相似文献
4.
The estimated yaw angles of the BeiDou I06 satellite demonstrated that the satellite experienced midnight- or noon-turn maneuvers when the sun elevation angle above the orbital plane (β angle) was in the range of [??3°, +?3°] and the orbital angle was in the range of approximately [??6°, 6°] or [174°, 186°]. The behavior of yaw attitude maneuvers in the vicinity of the midnight and noon points was identical. An alternative yaw attitude model similar to that used for the Galileo Full-Operation-Capacity (FOC) satellites was developed on the basis of the estimated BeiDou I06 yaw angles with an accuracy of approximately 3.4° to reproduce the yaw attitude behaviors. However, a discrepancy in the form of a reversal in yaw direction during the midnight-turn maneuver was observed for BeiDou I06 when the β angle was extremely small (<?0.1°). The derived yaw attitude model was proved to model the yaw attitude of the BeiDou-3 experimental satellites, and reduces the observation residuals in the vicinity of the midnight and noon points to normal levels, and facilitates continuous satellite clock estimation during eclipse periods. Compared to the yaw attitude model developed by the European Space Operations Centre (ESOC), a similar performance has been achieved with maximum yaw differences up to 9.2° when the β angle is close to 0°. The average agreement between the models is about 1°. However, the ESOC model was developed based on a patented eclipsing model, the developed model in this study is open access. 相似文献
5.
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
6.
We detail a low-cost method to estimate vehicle attitude for Satcom-on-the-move (SOTM) using micro inertial measurement unit and two-antenna global positioning system (GPS). The attitude is calculated by integrating gyros, while accelerometers and GPS are used as an aiding system to calibrate the gyro biases. In order to accurately eliminate the accelerometer errors induced by maneuvering accelerations, a sideslip compensation is proposed to calibrate the acceleration estimation derived from the GPS-measured velocity. An adaptive unscented Kalman filter is then developed to deal with the failure of the two-antenna GPS to provide the yaw and sideslip angles. When the yaw angle is unavailable and the vehicle is in straight motion, the yaw angle observation is substituted by velocity heading. During turning, the yaw angle observation is turned off and the yaw angle estimates are obtained from integrating gyros only. Meanwhile, the sideslip angle is estimated by differencing the yaw angle estimate and the velocity heading. The performance of the proposed method is demonstrated with driving tests, suggesting that this technique is a viable candidate for low-cost SOTM. 相似文献
7.
相比于单一卫星导航系统,多卫星导航系统组合具有显著增加可用卫星数目、改善卫星空间几何结构等优点,因而多卫星导航系统组合应用成为近年来关注的热点。在复杂观测条件下,利用BDS/GPS/GLONASS组合进行载体姿态测量具有单系统无法比拟的优势。首先阐述了BDS/GPS/GLONASS组合超短基线解算的双差模型以及姿态测量基本原理;然后分析了BDS/GPS/GLONASS组合多频单历元姿态测量性能。通过实测静态数据设置不同高度截止角进行分析表明:相比于单系统及双系统组合的姿态测量,BDS/GPS/GLONASS组合能够有效地提高姿态测量的精度、稳定性和可用性。当运动载体处于高楼、峡谷等受遮挡严重的复杂环境时,BDS/GPS/GLONASS组合单历元姿态测量更具有应用价值。 相似文献
8.
姿态模式切换期间QZSS卫星轨道及其钟差产品特性分析 总被引：1，自引：1，他引：0
导航卫星姿态控制模式切换对精密定轨解算得到的轨道和钟差均有较大影响。本文首先从理论上分析了卫星偏航姿态及其对精密定轨的影响,然后分别以卫星激光测距检核和钟差多项式拟合的方法对IGS MGEX分析中心的QZSS卫星轨道和钟差产品精度进行评价,最后以谱分析方法和改进阿伦方差揭示了卫星钟差的周期特性。基于2014年全年的QZSS卫星轨道和钟差产品的研究表明,一年内有两次长约20 d的地影季,太阳角呈现半年周期的波动;QZSS卫星在低太阳角时有零偏保护,其卫星轨道和钟差精度都与太阳角有显著相关性;卫星钟差具有与轨道周期相近的周期项,且周期项振幅与太阳角的大小也具有相关性,表明现有的定轨策略存在不足。考虑到QZSS与目前北斗星座中IGSO和MEO卫星姿态控制模式的相似性,该结论对于研究我国BDS姿态切换期间的精密定轨有一定参考价值。 相似文献
9.
10.
High precision geodetic applications of the Global Positioning System (GPS) require highly precise ephemerides of the GPS satellites. An accurate model for the non-gravitational forces on the GPS satellites is a key to high quality GPS orbit determination, especially in long arcs. In this paper the effect of the satellite solar panel orientation error is investigated. These effects are approximated by empirical functions to model the satellite attitude variation in long arc orbit fit. Experiments show that major part of the long arc GPS orbit errors can be accommodated by introducing a periodic variation of the satellite solar panel orientation with respect to the satellite-Sun direction, the desired direction for solar panel normal vector, with an amplitude of about 1 degree and with a frequency of once per orbit revolution. 相似文献
11.
Results are presented for Michibiki, the first satellite of Japan’s Quasi-Zenith Satellite System. Measurements for the analysis
have been collected with five GNSS tracking stations in the service area of QZSS, which track five of the six signals transmitted
by the satellite. The analysis discusses the carrier-to-noise density ratio as measured by the receiver for the different
signals. Pseudorange noise and multipath are evaluated with dual-frequency and triple-frequency combinations. QZSS uses two
separate antennas for signal transmission, which allows the determination of the yaw orientation of the spacecraft. Yaw angle
estimation results for an attitude mode switch from yaw-steering to orbit-normal orientation are presented. Estimates of differential
code biases between QZSS and GPS observations are shown in the analysis of the orbit determination results for Michibiki.
The estimated orbits are compared with the broadcast ephemerides, and their accuracy is assessed with overlap comparisons. 相似文献
12.
基于几何约束的GPS测姿系统的原理和实验 总被引：1，自引：0，他引：1
详细描述了GPS测姿系统的原理,并给出了一种基于基线长度约束和空间几何约束的最小二乘模糊度搜索算法,并经过静态和动态车载试验证明GPS测姿系统切实可行,在基线长度为3m的条件下,航向角精度优于0.1°。 相似文献
13.
风云3号B星(FY-3B)上的微波成像仪(MWRI)通过10.65 GHz,18.7 GHz,23.8GHz,36.5 GHz和189.0 GHz5个频率的双极化通道对地球表面进行监测。自卫星发射至今,MWRI资料的地理定位误差还未进行深入研究。为了提高FY-3B MWRI L1级数据地理定位精度,基于海、陆响应的升、降轨亮温差理论NDM(Node Differential Method),通过卫星位置和速度矢量建立卫星姿态模型、采用非线性最优化方法估计卫星姿态偏差,进而对MWRI 89 GHz通道的地理定位误差进行分析与订正。结果表明,2015年1—9月份俯仰、滚动和偏航角度的平均偏差分别为-0.220°,0.068°和0.062°,对应沿轨误差大约3—4 km,跨轨误差小于1 km。定位误差订正后,地中海、澳大利亚区域海岸线附近的升降轨亮温差明显减小;观测亮温在红海和南美洲东南部区域的分布和海岸线更加吻合,定位精度得到明显提高。 相似文献
14.
随着我国北斗卫星导航系统建设的逐步完善以及北斗应用的迅速推广,BD2/GPS定位终端设备已经开始广泛地应用于各个领域中.介绍了BD2/GPS双系统四频高精度接收机在远望号测量船船姿测量中的应用;并与传统的单一GPS接收机的测姿精度进行比对,分析北斗卫星导航系统在姿态测量中的作用与优势. 相似文献
15.
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
16.
精密单点定位（PPP）一般基于非差GPS观测值,其中相位观测所含的初始相位偏差（Initial Phase Biases, IPBs）与整周模糊度不可分离,故各类PPP估值均为模糊度浮点解。目前,借助区域或全球GPS网分离卫星IPBs,改正PPP相位观测值,可实现PPP整周模糊度解算,进而提高各类估值精度,显著缩短收敛时间。常用算法包括：分解卫星钟差（分解钟差法）和非整相位偏差（非整偏差法）估计方法。本文从GPS原始观测值入手,推导了卫星IPBs估计的满秩函数模型,以此为基础对两种算法的特点及实施进行了对比分析。研究表明：分解钟差法是一种观测信息的最优利用,且与传统的卫星钟差估计方法具有较优的一致性,但未利用卫星IPBs较为稳定的有利约束;非整偏差法对组合观测值之间的相关性未加考虑,进而是一种次优估计,其实时性实施较差,且较依赖于高精度的码观测值。文中的新模型可有效克服上述两种算法的不足,便于施加部分参数的合理时变性约束,以提高卫星IPBs估计的可靠性。 相似文献
17.
星载GPS地球静止轨道卫星自主定轨的新算法 总被引：1，自引：0，他引：1
针对地球静止轨道卫星的特点，提出了一种自主定轨的新算法——积分滤波算法，即利用Kalman滤波进行动力学模型数值积分与GPS定轨的有效融合。讨论了该算法的基本过程及其中Kalman滤波的数学模型和重要参数。最后给出了仿真实验过程和结果，证明了该算法的可行性。 相似文献
18.
针对移动测量系统对载体姿态的需求,对车载三天线全球卫星导航系统（global navigation satellite system,GNSS）的直接法定姿进行了研究。分析了定姿的原理,给出了姿态解算公式,并提出一种简便的方法确定航向角的象限,解决了航向角的多值性问题。为了评估该方法的精度,利用车载的三天线GNSS进行了动态实验,采集了动态观测数据,利用直接法对观测数据进行了姿态解算,并用同车搭载的一套高精度惯性导航系统（inertial navigation system,INS）给出的姿态参考值对三天线GNSS定姿的精度和可靠性进行了评估。结果表明,三天线GNSS直接法定姿精度高、可靠性好,并具有计算简便,可避免奇异性问题等优点。 相似文献
19.
This paper describes a low earth orbiter micro-satellite attitude determination algorithm using GPS phase and pseudorange
data as the only observables. It is designed to run in real-time, at a rate of 10 Hz, on-board the spacecraft, using minimal
chip and memory resources. The spacecraft design includes four GPS antennas deployed on boom arms to improve the antenna separations.
The boom arms feature smart sensors, from which time-varying deformation data are used to calculate changes in the body-fixed
system (BFS) co-ordinates of the attitude antennas. These data are used as input to the attitude algorithm to improve the
accuracy of the output.
The conventional double-difference phase observation equations have been re-arranged so that the only unknown parameters in
the functions (once the ambiguities have been determined) are the spacecraft Euler angles. This greatly increases the redundancy
in the mathematical model, and is exploited to enhance the algorithm's ability to trap observations contaminated by unmodelled
multipath. This approach has been shown to be successful in identifying phase outliers at the 5–10 mm level. Speed of execution
of the program is improved by utilising numerical differentiation of the model equations in the linearisation process. Furthermore,
as the number of solve-for parameters is reduced to three by the chosen mathematical model, matrix inversion requirements
are minimised. A novel approach to ambiguity resolution and determination of initial estimates of the attitude parameters
has been developed utilising a heuristic technique and the known, and time varying, BFS co-ordinates of the antenna array.
Algorithm testing is based on a simulation of the micro-satellite trajectory combined with variations in attitude derived
from spin-stabilisation and periodic roll and pitch parameters. The trajectory of the spacecraft centre of mass was calculated
by numerical integration of a force model using Earth gravity field parameters, third body effects due to the Sun and the
Moon, dynamic Earth tide effects (solar and lunar), and a solar radiation pressure model. Frame transformations between J2000
and ITRF97 used the IERS conventions. A similar approach was used to calculate the trajectories of all available GPS satellites
during the same period, using initial conditions of position and velocity from IGS precise orbits. RMS differences between
the published precise orbit and the integrated satellite positions were at the 5-mm level. Phase observables are derived from
these trajectories, biased by simulation of receiver and satellite clock errors, cycle slips, random or systematic noise and
initial integer ambiguities. In the actual simulation of the attitude determination process in orbit, GPS satellite positions
are calculated using broadcast ephemerides.
The results show that the aim of 0.05° (two sigma) attitude precision can be met provided that the phase noise can be reduced
to the level of 1–2 mm. Attitude precision was found to vary strongly with constellation geometry, which can change quite
rapidly depending on the variations in spacecraft attitude. The redundancy in the mathematical model was found to be very
effective in trapping and isolating cycle slips to the double difference observations that are contaminated. This allows for
the possibility of correcting for cycle slips without full recourse to the ambiguity resolution algorithm.
Electronic Publication 相似文献
20.
描述一种基于非专用接收机的GPS实时定姿算法,主要工作可以分为两个部分:第一,采用最小二乘方法和乔里斯基分解,基于基线长度约束压缩整周模糊度搜索空间,以达到实时计算的目的;第二,结合姿态角约束,使用金字塔算法提高了整周模糊度求解效率.经过实验,算法在基线长度为3 m的条件下,航向角精度优于0.1°. 相似文献