共查询到20条相似文献，搜索用时 46 毫秒
1.
Orbit determination of the SELENE satellites using multi-satellite data types and evaluation of SELENE gravity field models 总被引：1，自引：0，他引：1
S. Goossens K. Matsumoto D. D. Rowlands F. G. Lemoine H. Noda H. Araki 《Journal of Geodesy》2011,85(8):487-504
The SELENE mission, consisting of three separate satellites that use different terrestrial-based tracking systems, presents
a unique opportunity to evaluate the contribution of these tracking systems to orbit determination precision. The tracking
data consist of four-way Doppler between the main orbiter and one of the two sub-satellites while the former is over the far
side, and of same-beam differential VLBI tracking between the two sub-satellites. Laser altimeter data are also used for orbit
determination. The contribution to orbit precision of these different data types is investigated through orbit overlap analysis.
It is shown that using four-way and VLBI data improves orbit consistency for all satellites involved by reducing peak values
in orbit overlap differences that exist when only standard two-way Doppler and range data are used. Including laser altimeter
data improves the orbit precision of the SELENE main satellite further, resulting in very smooth total orbit errors at an
average level of 18 m. The multi-satellite data have also resulted in improved lunar gravity field models, which are assessed
through orbit overlap analysis using Lunar Prospector tracking data. Improvements over a pre-SELENE model are shown to be
mostly in the along-track and cross-track directions. Orbit overlap differences are at a level between 13 and 21 m with the
SELENE models, depending on whether 1-day data overlaps or 1-day predictions are used. 相似文献
2.
由SGM100i质量分析看SELENE的贡献 总被引：2，自引：0，他引：2
月球重力场是研究月球演化和深部构造的基本物理量,也是低轨月球卫星精密定轨的关键。SELENE以高-低卫星跟踪卫星模式历史上首次获得了月球背面重力场直接观测数据。与GLGM-3相比,增加了SELENE跟踪数据的SGM100i在各方面表现出较高的精度:其位系数误差阶方差在15～30阶减小超过10倍,最大达到66倍(15阶);位系数与地形的相关性系数在50～70阶高达0.9,而GLGM-3只有0.6～0.7;基于SGM100i计算的重力异常和月球大地水准面起伏也更好地揭示了月球背面与环形地形相关的重力场特征,从而验证了SELENE 4程Doppler数据对于月球重力场解算的贡献。 相似文献
3.
4.
Considering present attempts to develop a gradiometer with an accuracy between 10−3
E and 10−4
E, two applications for such a device have been studied: (a) mapping the gravitational field of the Earth, and (b) estimating
the geocentric distance of a satellite carrying the instrument. Given a certain power spectrum for the signal and 10−4
E (rms) of white measurement noise, the results of an error analysis indicate that a six-month mission in polar orbit at a height
of 200 km, with samples taken every three seconds, should provide data for estimating the spherical harmonic potential coefficients
up to degree and order 300 with less than 50% error, and improve the coefficients through degree 30 by up to four orders of
magnitude compared to existing models. A simulation study based on numerical orbit integrations suggests that a simple adjustment
of the initial conditions based on gradiometer data could produce orbits where the geocentric distance is accurate to 10 cm
or better, provided the orbits are 2000 km high and some improvement in the gravity field up to degree 30 is first achieved.
In this sense, the gravity-mapping capability of the gradiometer complements its use in orbit refinement. This idea can be
of use in determining orbits for satellite altimetry. Furthermore, by tracking the gradiometer-carrying spacecraft when it
passes nearly above a terrestrial station, the geocentric distance of this station can also be estimated to about one decimeter
accuracy. This principle could be used in combination with VLBI and other modern methods to set up a world-wide 3-D network
of high accuracy. 相似文献
5.
天问一号是中国首次独立开展的行星际探测任务,实现了对火星的环绕、着陆、巡视探测。天问一号正常科学任务阶段环绕以极轨设计为主,与历史火星任务类似,对当前火星重力场模型精度改进有限,因此其拓展任务轨道选取至关重要。通过对极轨圆轨道和近赤道大偏心率轨道进行仿真模拟,分析两种典型轨道构型对现有火星重力场模型改进的可能性,基于不同误差考量仿真解算了对应6个重力场模型。借助重力场功率谱分析,发现在测量噪声为0.1 mm/s的情况下,不论采用极轨还是近赤道轨道,一个月的跟踪数据均可较好地反演出42阶次的火星重力场模型;考虑综合误差影响之后,发现两种轨道对于重力场解算精度类似,其中实施近赤道大偏心率轨道对35阶次以上约束略强。 相似文献
6.
2006-05-29~2006-06-02,有关单位利用欧空局(ESA)的SMART-1环月飞行器进行了USB-VLBI综合测定轨试验,其中一个重要目标就是考察环月飞行器的短弧快速轨道确定能力。这里对综合测轨数据的精度进行了评估,分析了不同类型测轨数据组合和定轨弧长对短弧定轨和预报的影响。利用5 d测量数据进行统计:VLBI时延的RMS约为1 m,时延率的RMS约为0.25 cm/s,USB测速的RMS约为3~6 cm/s,测距的RMS约为1~3 m。30 min定轨及预报一个环月轨道周期(5 h)位置的RMS约为250 m,速度的RMS约为15 cm/s。 相似文献
7.
A preliminary error analysis of the gravity field recovery from a lunar Satellite-to-Satellite mission 总被引：2，自引：0，他引：2
Hüseyin Bâki Iz 《Journal of Geodesy》1993,67(3):173-177
Summary A low cost lunar Satellite-to-Satellite radio tracking mission in a low-low configuration could considerably improve the existing knowledge about the lunar gravity field. The impact of various mission parameters that may contribute to the recovery of the gravity field, such as satellite altitude, satellite separation, mission duration, measurement precision and sampling interval were quantified using the Jekeli-Rapp algorithm. Preliminary results indicate that the gravity field resolution up to harmonic degree 40 to 80 is feasible depending on various mission configurations. Radio tracking data from a six-month mission with a precision of 1 mm s–1 every 10 s and 300 km satellite separation at 150 km altitude will permit the determination of 5o×5o mean gravity anomalies with an error of approximately 15 mgals. Consideration of other unaccounted error sources of instrumental, operational as well as environmental nature may lower this resolution. 相似文献
8.
采用星载GPS观测数据与简化动力学定轨方法,在方程中引入伪随机脉冲参数,从而实现对Swarm卫星的精密定轨. 详细分析了不同阶次的GOCO06s地球重力场模型对Swarm卫星简化动力学定轨精度的影响,对比了PGM2000a、EIGEN-2、EGM2008以及GECO重力场模型展开到100阶次时Swarm卫星解算的轨道精度. 结果表明:当GOCO06s地球重力场模型阶次处于30～100阶次时,Swarm-A、Swarm-B和Swarm-C卫星在径向、切向、法向上的定轨精度随着GOCO06s阶次的不断增加而越来越高,而在高于100阶次时,定轨精度基本稳定,且在各方向定轨精度优于3 cm. 此外,采用100阶次GECO、EGM2008和GOCO06s模型对三颗Swarm卫星进行定轨,解算的轨道精度相当,且要高于同阶次其他重力场模型的定轨结果. 相似文献
9.
GOCE: precise orbit determination for the entire mission 总被引：4，自引：3，他引：1
The Gravity field and steady-state Ocean Circulation Explorer (GOCE) was the first Earth explorer core mission of the European Space Agency. It was launched on March 17, 2009 into a Sun-synchronous dusk-dawn orbit and re-entered into the Earth’s atmosphere on November 11, 2013. The satellite altitude was between 255 and 225 km for the measurement phases. The European GOCE Gravity consortium is responsible for the Level 1b to Level 2 data processing in the frame of the GOCE High-level processing facility (HPF). The Precise Science Orbit (PSO) is one Level 2 product, which was produced under the responsibility of the Astronomical Institute of the University of Bern within the HPF. This PSO product has been continuously delivered during the entire mission. Regular checks guaranteed a high consistency and quality of the orbits. A correlation between solar activity, GPS data availability and quality of the orbits was found. The accuracy of the kinematic orbit primarily suffers from this. Improvements in modeling the range corrections at the retro-reflector array for the SLR measurements were made and implemented in the independent SLR validation for the GOCE PSO products. The satellite laser ranging (SLR) validation finally states an orbit accuracy of 2.42 cm for the kinematic and 1.84 cm for the reduced-dynamic orbits over the entire mission. The common-mode accelerations from the GOCE gradiometer were not used for the official PSO product, but in addition to the operational HPF work a study was performed to investigate to which extent common-mode accelerations improve the reduced-dynamic orbit determination results. The accelerometer data may be used to derive realistic constraints for the empirical accelerations estimated for the reduced-dynamic orbit determination, which already improves the orbit quality. On top of that the accelerometer data may further improve the orbit quality if realistic constraints and state-of-the-art background models such as gravity field and ocean tide models are used for the reduced-dynamic orbit determination. 相似文献
10.
月球重力场可用来研究月球演化过程和内部结构,是影响绕月卫星精密定轨的重要因素。基于GRAIL任务数据解算的GL0660B重力场模型,极大提高了月球重力场空间频谱信号的强度和范围。本文首先通过计算相应重力场的阶方差和地形相关性分析,对GL0660B模型进行了精度分析;其次,利用GL0660B模型和其他几个月球重力场模型进行比较,对月球重力场的特征进行了分析;然后通过绘制GL0660B模型和LP150Q模型在月球外部不同高度处的重力异常图,分析比较了月球重力场模型在不同高度上所反映的月球重力场的特征和差异;最后,利用GEODYN软件模拟计算了不同高度卫星的轨道变化。可以看出绕月卫星离心率随时间的变化,以及周期性变化趋势,而且不同高度卫星轨道处质量瘤的摄动影响不同,远月点、近月点和偏心率的变化也存在差异。 相似文献
11.
Validation of GOCE gravity field models by means of orbit residuals and geoid comparisons 总被引：6，自引：3，他引：3
Three GOCE-based gravity field solutions have been computed by ESA’s high-level processing facility and were released to the
user community. All models are accompanied by variance-covariance information resulting either from the least squares procedure
or a Monte-Carlo approach. In order to obtain independent external quality parameters and to assess the current performance
of these models, a set of independent tests based on satellite orbit determination and geoid comparisons is applied. Both
test methods can be regarded as complementary because they either investigate the performance in the long wavelength spectral
domain (orbit determination) or in the spatial domain (geoid comparisons). The test procedure was applied to the three GOCE
gravity field solutions and to a number of selected pre-launch models for comparison. Orbit determination results suggest,
that a pure GOCE gravity field model does not outperform the multi-year GRACE gravity field solutions. This was expected as
GOCE is designed to improve the determination of the medium to high frequencies of the Earth gravity field (in the range of
degree and order 50 to 200). Nevertheless, in case of an optimal combination of GOCE and GRACE data, orbit determination results
should not deteriorate. So this validation procedure can also be used for testing the optimality of the approach adopted for
producing combined GOCE and GRACE models. Results from geoid comparisons indicate that with the 2 months of GOCE data a significant
improvement in the determination of the spherical harmonic spectrum of the global gravity field between degree 50 and 200
can be reached. Even though the ultimate mission goal has not yet been reached, especially due to the limited time span of
used GOCE data (only 2 months), it was found that existing satellite-only gravity field models, which are based on 7 years
of GRACE data, can already be enhanced in terms of spatial resolution. It is expected that with the accumulation of more GOCE
data the gravity field model resolution and quality can be further enhanced, and the GOCE mission goal of 1–2 cm geoid accuracy
with 100 km spatial resolution can be achieved. 相似文献
12.
Differential tracking of theGPS satellites in high-earth orbit provides a powerful relative positioning capability, even when a relatively small continental
U.S. fiducial tracking network is used with less than one-third of the fullGPS constellation. To demonstrate this capability, we have determined baselines of up to2000 km in North America by estimating high-accuracyGPS orbits and ground receiver positions simultaneously. The2000 km baselines agree with very long baseline interferometry(VLBI) solutions at the level of1.5 parts in10
8 and showrms daily repeatability of0.3–2 parts in10
8. The orbits determined for the most thoroughly trackedGPS satellites are accurate to better than1 m. GPS orbit accuracy was assessed from orbit predictions, comparisons with independent data sets, and the accuracy of the continental
baselines determined along with the orbits. The bestGPS orbit strategies included data arcs of at least one week, process noise models for tropospheric fluctuations, estimation
ofGPS solar pressure coefficients, and combined processing ofGPS carrier phase and pseudorange data. For data arcs of two weeks, constrained process noise models forGPS dynamic parameters significantly improved the solutions. 相似文献
13.
14.
15.
This analysis was performed with the GEOSAT software developed at NDRE for high-precision analysis of satellite tracking and VLBI data for geodetic and geodynamic applications.For applications to ERS-1, a realistic surface force model is used together with the Jacchia 77 atmospheric model, semi-daily drag coefficients, a 1-cpr sinusoidal along-track acceleration, and the GSFC JGM-2 gravity model. ERS-1 orbits have been derived for 5.5-day arcs of laser tracking data between July 6 and August 12, 1992. Results from overlapping orbits and comparison with precise D-PAF orbits indicate an orbital accuracy of 10–15 cm in the radial direction, ~ 60 cm in the along-track direction and ~ 15 cm in the cross-track direction. 相似文献
16.
When planning a satellite gravity gradiometer (SGG) mission, it is important to know the quality of the quantities to be recovered
at ground level as a function of e.g. satellite altitude, data type and sampling rate, and signal variance and noise. This
kind of knowledge may be provided either using the formal error estimates of wanted quantities using least-squares collocation
(LSC) or by comparing simulated data at ground level with results computed by methods like LSC or Fast Fourier Transform (FFT).
Results of a regional gravity field recovery in a 10o×20o area surrounding the Alps using LSC and FFT are reported. Data used as observations in satellite altitude (202 or161 km) and for comparison at ground level were generated using theOSU86F coefficient set, complete to degree 360. These observations are referred to points across simulated orbits. The simulated
quantities were computed for a 45 days mission period and 4 s sampling. A covariance function which also included terms above
degree 360 was used for prediction and error estimation. This had the effect that the formal error standard deviation for
gravity anomalies were considerably larger than the standard deviations of predicted minus simulated quantities. This shows
the importance of using data with frequency content above degree 360 in simulation studies. Using data at202 km altitude the standard deviation of the predicted minus simulated data was equal to8.3 mgal for gravity and0.33 m for geoid heights. 相似文献
17.
研发了一套具有自主知识产权的火星探测器精密定轨及动力学参数解算软件系统，介绍了软件的设计思路与基本结构。对2009年8月中国甚长基线干涉测量网跟踪的火星快车号三程多谱勒数据和相同弧段欧洲空间局的双程多谱勒数据进行了处理。结果表明，对于三程多谱勒数据，精密定轨后的残差处于0.079 mm/s的水平，轨道与比利时皇家天文台发布的火星快车精密轨道（精度20~25 m）最大差距小于100 m；对于欧洲空间局双程多谱勒数据，精密定轨后的残差处于0.067 mm/s的水平，轨道与精密轨道最大差距小于10 m。对火星快车跟踪数据的处理结果表明该软件可靠。 相似文献
18.
19.
The consistency of the Chang’E-1 and SELENE reference frames as realized by the footprint positions of laser altimetry measurements
of the lunar surface during both missions was analyzed using a global 12-parameter model for small (with respect to unity)
deformations and rigid body motions. The rigid body motion and deformation parameters between the two reference frames estimated
from nearly-colocated without tie measurements are found to be consistent, i.e., nearly zero for the estimates of the translations,
rotations and shear parameters. However, the estimated three strain parameters, which are similar in magnitude and sign, reveal
a prominent scale difference, between the Chang’E-1 and SELENE reference frames, of about 0.9 × 10−5. The scale difference can be attributed to calibration of the data sets using the known coordinates of the lunar laser ranging
stations all located on the near side of the Moon. 相似文献
20.
Design considerations for a dedicated gravity recovery satellite mission consisting of two pairs of satellites 总被引：5，自引：0，他引：5
Future satellite missions dedicated to measuring time-variable gravity will need to address the concern of temporal aliasing
errors; i.e., errors due to high-frequency mass variations. These errors have been shown to be a limiting error source for
future missions with improved sensors. One method of reducing them is to fly multiple satellite pairs, thus increasing the
sampling frequency of the mission. While one could imagine a system architecture consisting of dozens of satellite pairs,
this paper explores the more economically feasible option of optimizing the orbits of two pairs of satellites. While the search
space for this problem is infinite by nature, steps have been made to reduce it via proper assumptions regarding some parameters
and a large number of numerical simulations exploring appropriate ranges for other parameters. A search space originally consisting
of 15 variables is reduced to two variables with the utmost impact on mission performance: the repeat period of both pairs
of satellites (shown to be near-optimal when they are equal to each other), as well as the inclination of one of the satellite
pairs (the other pair is assumed to be in a polar orbit). To arrive at this conclusion, we assume circular orbits, repeat
groundtracks for both pairs of satellites, a 100-km inter-satellite separation distance, and a minimum allowable operational
satellite altitude of 290 km based on a projected 10-year mission lifetime. Given the scientific objectives of determining
time-variable hydrology, ice mass variations, and ocean bottom pressure signals with higher spatial resolution, we find that
an optimal architecture consists of a polar pair of satellites coupled with a pair inclined at 72°, both in 13-day repeating
orbits. This architecture provides a 67% reduction in error over one pair of satellites, in addition to reducing the longitudinal
striping to such a level that minimal post-processing is required, permitting a substantial increase in the spatial resolution
of the gravity field products. It should be emphasized that given different sets of scientific objectives for the mission,
or a different minimum allowable satellite altitude, different architectures might be selected. 相似文献