首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
工程化广播星历参数拟合算法与接口设计   总被引:1,自引:0,他引:1  
对导航卫星广播星历参数拟合算法和接口设计问题进行了研究。通过条件数、参数相关性分析,指出小倾角问题是造成GPS开普勒轨道根数广播星历拟合算法不能适用于GEO卫星的最主要原因;通过分析定轨理论和拟合实例证明,GEO卫星星历参数Crc、Crs超限的主要原因是由于其轨道特性决定的;针对GEO卫星星历参数拟合法方程严重病态的问题,提出了动态加权的带参数约束条件平差算法。该方法能有效稳定星历拟合结果,解决Δn等星历参数超限的问题。  相似文献   

2.
Computation of broadcast ephemerides is a fundamental task in satellite navigation and positioning. The GPS constellation is composed of medium-earth-orbit (MEO) satellites, and therefore can employ a uniform parameter set to produce broadcast ephemerides. However, other navigation satellite systems such as Compass and IRNSS may include a mixture of inclined-geosynchronous-orbit (IGSO), geostationary-earth-orbit (GEO) and MEO satellites, requiring different parameter sets for each type of orbit. We analyze the variational characteristics of satellite ephemerides with respect to orbital elements; then present a method to design an optimal parameter set for broadcast ephemerides, and derive the parameter sets for IGSO, GEO, and MEO satellites. The computational complexities of the user algorithms for the optimal parameter sets are equivalent to that of the standard GPS user algorithm. Simulation and statistical analyses indicate that the optimal parameter set is $ \left\{ {\sqrt {A_{0} } ,e_{0} ,i_{0} ,\Upomega_{0} ,M_{0} ,\omega_{0} ,\dot{\Upomega },\dot{u},\dot{i},C_{\Upomega c3} ,C_{\Upomega s3} ,C_{uc2} ,C_{us2} ,C_{rc2} ,C_{rs2} } \right\} $ for IGSO and GEO satellites, and $ \left\{ {\sqrt {A_{0} } ,e_{0} ,i_{0} ,\Upomega_{0} ,M_{0} ,\omega_{0} ,\dot{\Upomega },\dot{u},\dot{i},C_{uc2} ,C_{us2} ,C_{rc2} ,C_{rs2} ,C_{ic2} ,C_{is2} } \right\} $ for MEO satellites.  相似文献   

3.
广播星历参数拟合算法研究   总被引:7,自引:0,他引:7  
导航卫星一般采用近圆轨道,当卫星轨道偏心率或者轨道倾角接近于0时,利用GPS卫星开普勒轨道根数拟合卫星广播星历会出现一些问题。当高轨卫星轨道偏心率接近0时,广播星历拟合精度下降甚至拟合失败,为此本文提出了减少拟合参数个数、固定轨道根数M0或者延长星历参数拟合弧段长度的方法;针对GEO卫星在小倾角情况下,广播星历可能拟合失败的情况,本文提出了改变坐标系参考轨道面,在新的坐标系下拟合广播星历的方法。结果表明,改进后的拟合方法能适用于各种类型的导航卫星轨道,拟合精度在cm级或者mm级。  相似文献   

4.
随着北斗三号卫星导航系统(BeiDou navigation satellite system-3, BDS-3)开始向全球提供导航服务,独立使用BDS为在轨运行的卫星提供全球覆盖、全时段的定位服务成为可能。结合风云三号D星(FengYun-3D, FY-3D)全球卫星导航系统掩星探测仪(global navigation satellite system occultation sounder, GNOS)的真实在轨数据对天基BDS的定位性能进行了详细的分析。首先,使用BDS真实广播星历计算了在不同轨道高度下的可见卫星数和定位精度因子(position dilution of precision, PDOP),并结合精密星历分析了广播星历的轨道误差、时钟误差及空间信号测距误差(signal-in-space range error, SISRE)。仿真结果表明,在95%的置信水平下,从地面到2 000 km的轨道高度,BDS在全球范围内最小可见卫星数为6,最大PDOP小于5,星座可用性已经达到100%,全球平均可见卫星数BDS比GPS(global positioning syste...  相似文献   

5.
Continued advancements in remote sensing technology along with a trend towards highly autonomous spacecraft provide a strong motivation for accurate real-time navigation of satellites in low Earth orbit (LEO). Global Navigation Satellite System (GNSS) sensors nowadays enable a continuous tracking and provide low-noise radiometric measurements onboard a user spacecraft. Following the deactivation of Selective Availability a representative real-time positioning accuracy of 10 m is presently achieved by spaceborne global positioning system (GPS) receivers on LEO satellites. This accuracy can notably be improved by use of dynamic orbit determination techniques. Besides a filtering of measurement noise and other short-term errors, these techniques enable the processing of ambiguous measurements such as carrier phase or code-carrier combinations. In this paper a reference algorithm for real-time onboard orbit determination is described and tested with GPS measurements from various ongoing space missions covering an altitude range of 400–800 km. A trade-off between modeling effort and achievable accuracy is performed, which takes into account the limitations of available onboard processors and the restricted upload capabilities. Furthermore, the benefits of different measurements types and the available real-time ephemeris products are assessed. Using GPS broadcast ephemerides a real-time position accuracy of about 0.5 m (3D rms) is feasible with dual-frequency carrier phase measurements. Slightly inferior results (0.6–1 m) are achieved with single-frequency code-carrier combinations or dual-frequency code. For further performance improvements the use of more accurate real-time GPS ephemeris products is mandatory. By way of example, it is shown that the TDRSS Augmentation Service for Satellites (TASS) offers the potential for 0.1–0.2 m real-time navigation accuracies onboard LEO satellites.  相似文献   

6.
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   

7.
为了及时评估北斗三号全球卫星导航系统(BDS-3)广播星历的精度,本文基于2018年3月10—22日和2019年7月2—14日的BDS-2、BDS-3广播星历,以及武汉大学发布的精密星历数据,从北斗卫星的星历误差、轨道误差和空间信号测距精度(SISRE)3个方面进行了全面比较与分析。结果表明:BDS-3的广播星历星历误差的RMSE基本优于1.5 m,BDS-2的GEO、IGSO和MEO卫星的广播卫星星历误差的RMSE分别为3.0、3.0、2.0 m;BDS-3的轨道误差RMSE基本优于1.0 m,其中径向R方向的精度高于切向T和法线N方向,分别为0.1、1.0、0.5 m,BDS-2在R、T、N 3个方向上的精度分别为1、3、3 m;BDS-3广播星历SISRE的RMSE基本优于0.25 m,BDS-2的GEO、IGSO和MEO卫星的SISRE分别优于0.5、2.0、0.5 m。本文的结果整体上反映出BDS-3信号稳定且精度逐渐提升。  相似文献   

8.
王乐  张勤  黄观文  燕兴元  秦志伟 《测绘学报》2016,45(Z2):101-108
我国北斗二代系统(BDS)地面运控监测站数量较少且为区域分布,短期内难以实现全球建站,因此对全球运行的中圆地球轨道卫星(MEO)难以形成连续多重覆盖观测,导致BDS的MEO实时轨道精度偏低。基于上述问题,本文考虑到低轨卫星星载GNSS数据可以有效弥补区域监测站在空间覆盖及几何结构上的不足,设计了一种将星载GNSS接收机作为高动态天基监测站,联合地面区域监测站数据对卫星导航系统的MEO卫星轨道进行实时解算预报的方法。算例结果显示:7个区域监测站联合1至3个天基监测站,其定轨精度可分别提升约21%、34%和55%,这也表明,地面区域监测站联合天基低轨卫星数据可有效提高MEO卫星的轨道精度。建议我国BDS在区域测站分布阶段可采用联合低轨卫星数据方法提高北斗MEO卫星实时轨道精度。  相似文献   

9.
介绍基于坐标选转法的GEO广播星历拟合算法,推导坐标系旋转前后卫星瞬时轨道根数及其摄动的解析关系式,分析选择不同惯性系(不同的X轴指向和不同旋转角)对卫星轨道根数及其摄动的影响,通过仿真GEO轨道的广播星历拟合实验分析不同坐标旋转角度对星历参数拟合结果的影响。分析和试验表明:①采用简化法,经坐标变换后得到的轨道倾角不为常数,而是随着选择的参考历元不同呈周期性变化;②选择不同的惯性参考系会导致轨道倾角摄动以不同的放大倍数放大后被新坐标系的轨道升交点赤经摄动和近地点幅角摄动吸收,放大倍数可达几十倍至上百倍甚至出现奇点;③拟合得到的GEO卫星星历参数Δn和.Ω的取值范围随坐标旋转角的增大而减小。  相似文献   

10.
首先对GPS卫星的轨道定轨的原理进行了简单描述,以卫星的广播星历数据为基础,计算出卫星的16个轨道参数,进而得到该卫星任一时刻的瞬时坐标。以2017年4月7日的GPS07号卫星的广播星历数据为例,计算该GPS卫星当天的轨道坐标,并将结果与当天IGS提供的精密星历所提供的卫星轨道坐标进行比较,计算结果显示广播星历误差可达5 m。最后使用STK软件调用MATLAB软件读取数据进行仿真分析,模拟出卫星的轨道,并计算出卫星的坐标,数值结果可为轨道设计提供技术参考。  相似文献   

11.
Many geoscience disciplines push for ever higher requirements on accuracy, homogeneity and time- and space-resolution of the Earth’s gravity field. Apart from better instruments or new observables, alternative satellite formations could improve the signal and error structure compared to Grace. One possibility to increase the sensitivity and isotropy by adding cross-track information is a pair of satellites flying in a pendulum formation. This formation contains two satellites which have different ascending nodes and arguments of latitude, but have the same orbital height and inclination. In this study, the semi-analytical approach for efficient pre-mission error assessment is presented, and the transfer coefficients of range, range-rate and range-acceleration gravitational perturbations are derived analytically for the pendulum formation considering a set of opening angles. The new challenge is the time variations of the opening angle and the range, leading to temporally variable transfer coefficients. This is solved by Fourier expansion of the sine/cosine of the opening angle and the central angle. The transfer coefficients are further applied to assess the error patterns which are caused by different orbital parameters. The simulation results indicate that a significant improvement in accuracy and isotropy is obtained for small and medium initial opening angles of single polar pendulums, compared to Grace. The optimal initial opening angles are \(45^\circ \) and \(15^\circ \) for accuracy and isotropy, respectively. For a Bender configuration, which is constituted by a polar Grace and an inclined pendulum in this paper, the behaviour of results is dependent on the inclination (prograde vs. retrograde) and on the relative baseline orientation (left or right leading). The simulation for a sun-synchronous orbit shows better results for the left leading case.  相似文献   

12.
介绍广播星历精度评估的基本原理与方法,在此基础上利用长达两年的广播星历数据分析比较Galileo现有IOV卫星的广播轨道精度、钟差精度以及整体精度SISRE的长期和短期变化趋势,结果表明,目前Galileo IOV卫星径向轨道精度优于0.5m,切向精度优于1.8m,法向精度优于1.5m,略优于切向,钟差精度优于5ns,SISRE优于1.3m。从星历精度的长期变化趋势来看,Galileo广播星历精度随系统发展有一定的改善。  相似文献   

13.
Jan Rooba 《Journal of Geodesy》1983,57(1-4):138-145
Short-arc orbit computations by numerical or analytical integration of equations of motion traditionally utilized in geodetic and geodynamic satellite positioning are relatively involved and computationally expensive. However, short-arc orbits can be evaluated more efficiently by means of least squares polynomial approximations. Such orbit computations do not significantly increase the computation time when compared to widely used semi-short-arc techniques which utilize externally generated orbits. The sufficiently high-degree polynomial approximation of the second time derivatives , and evaluated from a gravitational potential model at regular (two-minute) intervals and everaged initial conditions (position and velocity vectors at the beginning, the middle and the end of a pass) reproduces the U.S. Defense Mapping Agency precise ephemeris of the Navy Navigation Satellites (NNSS) to about 5 cm RMS in each coordinate. To achieve this level of orbit shape resolution for NNSS satellites, the gravitational potential model should not be truncated at less than degree and order 10. Contribution of the Earth Physics Branch No. 1034.  相似文献   

14.
Large-scale mass redistribution in the terrestrial water storage (TWS) leads to changes in the low-degree spherical harmonic coefficients of the Earth’s surface mass density field. Studying these low-degree fluctuations is an important task that contributes to our understanding of continental hydrology. In this study, we use global GNSS measurements of vertical and horizontal crustal displacements that we correct for atmospheric and oceanic effects, and use a set of modified basis functions similar to Clarke et al. (Geophys J Int 171:1–10, 2007) to perform an inversion of the corrected measurements in order to recover changes in the coefficients of degree-0 (hydrological mass change), degree-1 (centre of mass shift) and degree-2 (flattening of the Earth) caused by variations in the TWS over the period January 2003–January 2015. We infer from the GNSS-derived degree-0 estimate an annual variation in total continental water mass with an amplitude of \((3.49 \pm 0.19) \times 10^{3}\) Gt and a phase of \(70^{\circ } \pm 3^{\circ }\) (implying a peak in early March), in excellent agreement with corresponding values derived from the Global Land Data Assimilation System (GLDAS) water storage model that amount to \((3.39 \pm 0.10) \times 10^{3}\) Gt and \(71^{\circ } \pm 2^{\circ }\), respectively. The degree-1 coefficients we recover from GNSS predict annual geocentre motion (i.e. the offset change between the centre of common mass and the centre of figure) caused by changes in TWS with amplitudes of \(0.69 \pm 0.07\) mm for GX, \(1.31 \pm 0.08\) mm for GY and \(2.60 \pm 0.13\) mm for GZ. These values agree with GLDAS and estimates obtained from the combination of GRACE and the output of an ocean model using the approach of Swenson et al. (J Geophys Res 113(B8), 2008) at the level of about 0.5, 0.3 and 0.9 mm for GX, GY and GZ, respectively. Corresponding degree-1 coefficients from SLR, however, generally show higher variability and predict larger amplitudes for GX and GZ. The results we obtain for the degree-2 coefficients from GNSS are slightly mixed, and the level of agreement with the other sources heavily depends on the individual coefficient being investigated. The best agreement is observed for \(T_{20}^C\) and \(T_{22}^S\), which contain the most prominent annual signals among the degree-2 coefficients, with amplitudes amounting to \((5.47 \pm 0.44) \times 10^{-3}\) and \((4.52 \pm 0.31) \times 10^{-3}\) m of equivalent water height (EWH), respectively, as inferred from GNSS. Corresponding agreement with values from SLR and GRACE is at the level of or better than \(0.4 \times 10^{-3}\) and \(0.9 \times 10^{-3}\) m of EWH for \(T_{20}^C\) and \(T_{22}^S\), respectively, while for both coefficients, GLDAS predicts smaller amplitudes. Somewhat lower agreement is obtained for the order-1 coefficients, \(T_{21}^C\) and \(T_{21}^S\), while our GNSS inversion seems unable to reliably recover \(T_{22}^C\). For all the coefficients we consider, the GNSS-derived estimates from the modified inversion approach are more consistent with the solutions from the other sources than corresponding estimates obtained from an unconstrained standard inversion.  相似文献   

15.
For science applications of the gravity recovery and climate experiment (GRACE) monthly solutions, the GRACE estimates of \(C_{20}\) (or \(J_{2}\)) are typically replaced by the value determined from satellite laser ranging (SLR) due to an unexpectedly strong, clearly non-geophysical, variation at a period of \(\sim \)160 days. This signal has sometimes been referred to as a tide-like variation since the period is close to the perturbation period on the GRACE orbits due to the spherical harmonic coefficient pair \(C_{22}/S_{22}\) of S2 ocean tide. Errors in the S2 tide model used in GRACE data processing could produce a significant perturbation to the GRACE orbits, but it cannot contribute to the \(\sim \)160-day signal appearing in \(C_{20}\). Since the dominant contribution to the GRACE estimate of \(C_{20}\) is from the global positioning system tracking data, a time series of 138 monthly solutions up to degree and order 10 (\(10\times 10\)) were derived along with estimates of ocean tide parameters up to degree 6 for eight major tides. The results show that the \(\sim \)160-day signal remains in the \(C_{20}\) time series. Consequently, the anomalous signal in GRACE \(C_{20}\) cannot be attributed to aliasing from the errors in the S2 tide. A preliminary analysis of the cross-track forces acting on GRACE and the cross-track component of the accelerometer data suggests that a temperature-dependent systematic error in the accelerometer data could be a cause. Because a wide variety of science applications relies on the replacement values for \(C_{20}\), it is essential that the SLR estimates are as reliable as possible. An ongoing concern has been the influence of higher degree even zonal terms on the SLR estimates of \(C_{20}\), since only \(C_{20}\) and \(C_{40}\) are currently estimated. To investigate whether a better separation between \(C_{20}\) and the higher-degree terms could be achieved, several combinations of additional SLR satellites were investigated. In addition, a series of monthly gravity field solutions (\(60\times 60\)) were estimated from a combination of GRACE and SLR data. The results indicate that the combination of GRACE and SLR data might benefit the resonant orders in the GRACE-derived gravity fields, but it appears to degrade the recovery of the \(C_{20}\) variations. In fact, the results suggest that the poorer recovery of \(C_{40}\) by GRACE, where the annual variation is significantly underestimated, may be affecting the estimates of \(C_{20}\). Consequently, it appears appropriate to continue using the SLR-based estimates of \(C_{20}\), and possibly also \(C_{40}\), to augment the existing GRACE mission.  相似文献   

16.
Model improvements and validation of TerraSAR-X precise orbit determination   总被引:3,自引:1,他引:2  
The radar imaging satellite mission TerraSAR-X requires precisely determined satellite orbits for validating geodetic remote sensing techniques. Since the achieved quality of the operationally derived, reduced-dynamic (RD) orbit solutions limits the capabilities of the synthetic aperture radar (SAR) validation, an effort is made to improve the estimated orbit solutions. This paper discusses the benefits of refined dynamical models on orbit accuracy as well as estimated empirical accelerations and compares different dynamic models in a RD orbit determination. Modeling aspects discussed in the paper include the use of a macro-model for drag and radiation pressure computation, the use of high-quality atmospheric density and wind models as well as the benefit of high-fidelity gravity and ocean tide models. The Sun-synchronous dusk–dawn orbit geometry of TerraSAR-X results in a particular high correlation of solar radiation pressure modeling and estimated normal-direction positions. Furthermore, this mission offers a unique suite of independent sensors for orbit validation. Several parameters serve as quality indicators for the estimated satellite orbit solutions. These include the magnitude of the estimated empirical accelerations, satellite laser ranging (SLR) residuals, and SLR-based orbit corrections. Moreover, the radargrammetric distance measurements of the SAR instrument are selected for assessing the quality of the orbit solutions and compared to the SLR analysis. The use of high-fidelity satellite dynamics models in the RD approach is shown to clearly improve the orbit quality compared to simplified models and loosely constrained empirical accelerations. The estimated empirical accelerations are substantially reduced by 30% in tangential direction when working with the refined dynamical models. Likewise the SLR residuals are reduced from \(-3\,\pm \,17\) to \(2\,\pm \,13\) mm, and the SLR-derived normal-direction position corrections are reduced from 15 to 6 mm, obtained from the 2012–2014 period. The radar range bias is reduced from \(-10.3\) to \(-6.1\) mm with the updated orbit solutions, which coincides with the reduced standard deviation of the SLR residuals. The improvements are mainly driven by the satellite macro-model for the purpose of solar radiation pressure modeling, improved atmospheric density models, and the use of state-of-the-art gravity field models.  相似文献   

17.
A neural network model for predicting weighted mean temperature   总被引:2,自引:0,他引:2  
Maohua Ding 《Journal of Geodesy》2018,92(10):1187-1198
Water vapor is an important element of the Earth’s atmosphere, and most of it concentrates at the bottom of the troposphere. Knowledge of the water vapor measured by Global Navigation Satellite Systems (GNSS) is an important direction of GNSS research. In particular, when the zenith wet delay is converted to precipitable water vapor, the weighted mean temperature \(T_\mathrm{m}\) is a variable parameter to be determined in this conversion. The purpose of the study is getting a more accurate \(T_\mathrm{m}\) model for global users by a combination of two different characteristics of \(T_\mathrm{m}\) (i.e., the \(T_\mathrm{m}\) seasonal variations and the relationships between \(T_\mathrm{m}\) and surface meteorological elements). The modeling process was carried out by using the neural network technology. A multilayer feedforward neural network model (the NN) was established. The NN model is used with measurements of only surface temperature \(T_\mathrm{S}\). The NN was validated and compared with four other published global \(T_\mathrm{m}\) models. The results show that the NN performed better than any of the four compared models on the global scale.  相似文献   

18.
We analyze the high-resolution dilatation data for the October 2013 \(M_w\) 6.2 Ruisui, Taiwan, earthquake, which occurred at a distance of 15–20 km away from a Sacks–Evertson dilatometer network. Based on well-constrained source parameters (\(\hbox {strike}=217^\circ \), \(\hbox {dip}=48^\circ \), \(\hbox {rake}=49^\circ \)), we propose a simple rupture model that explains the permanent static deformation and the dynamic vibrations at short period (\(\sim \)3.5–4.5 s) for most of the four sites with less than 20 % of discrepancies. This study represents a first attempt of modeling simultaneously the dynamic and static crustal strain using dilatation data. The results illustrate the potential for strain recordings of high-frequency seismic waves in the near-field of an earthquake to add constraints on the properties of seismic sources.  相似文献   

19.
LEO卫星轨道根数型星历参数与接口设计   总被引:1,自引:1,他引:0  
低轨卫星是导航增强系统发展的新兴力量,具有独特优势。广播星历参数是其实现星基增强的重要指标。中轨GPS星历采用16/18参数模型,若直接用于LEO的星历参数拟合,卫星沿迹方向的位置分量拟合误差大,且对小偏心率近圆轨道有潜在的拟合法矩阵病态问题。基于第一类无奇点根数,通过增加或修改轨道沿迹向和径向摄动参数,设计了适用于近圆低轨卫星的16~19参数的5种星历模型。基于300~1500 km高度LEO的拟合试验表明:提出的16/17/18/18~*/19参数星历,URE最大值分别优于10/6/4/5/2.5 cm。最后,根据拟合参数的变化范围,对5个星历模型进行了接口设计。在数据截断对URE的影响为毫米量级要求下,总比特位分别为329/343/376/379/396,其中16/17参数星历模型比GPS16参数模型减少了29/15个,18/18~*/19参数星历模型比GPS18参数星历模型减少了64/61/41个。  相似文献   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号