共查询到20条相似文献，搜索用时 62 毫秒
1.
卫星重力梯度测量任务将获取全球范围内高精度重力场信息。为利用重力梯度测量数据来提高重力场模型的精度,本文从球谐函数谱分析理论出发,导出了重力梯度场球谐谱分析的迭代算法公式。数值模拟结果表明：该迭代算法的收敛性极好,且高阶次位系数的收敛趋势较低阶次的收敛趋势要好得多。 相似文献
2.
Alberta Albertella Federica Migliaccio Fernando Sansó 《Celestial Mechanics and Dynamical Astronomy》2002,83(1-4):1-15
An artificial satellite, flying in a purely gravitational field is a natural probe, such that, by a very accurate orbit determination, would allow a perfect estimation of the field. A true satellite experiences a number of perturbational, non-gravitational forces acting on the shell of the spacecraft; these can be revealed and accurately measured by a spaceborne accelerometer. If more accelerometers are flown in the same satellite, they naturally eliminate (to some extent) the common perturbational accelerations and their differences are affected by the second derivatives of the gravity fields only (gradiometry). The mission GOCE is based on this principle. Its peculiar dynamical observation equations are reviewed. The possibility of estimating the gravity field up to some harmonic degree (200) is illustrated. 相似文献
3.
R. Rummel 《Earth, Moon, and Planets》2004,94(1-2):3-11
Precise global geoid and gravity anomaly information serves essentially three different kinds of applications in Earth sciences:
gravity and geoid anomalies reflect density anomalies in oceanic and continental lithosphere and the mantle; dynamic ocean
topography as derived from the combination of satellite altimetry and a global geoid model can be directly transformed into
a global map of ocean surface circulation; any redistribution or exchange of mass in Earth system results in temporal gravity
and geoid changes. After completion of the dedicated gravity satellite missions GRACE and GOCE a high standard of global gravity
determination, both of the static and of the time varying field will be attained. Thus, it is the right time to investigate
the future needs for improvements in the various fields of Earth sciences and to define the right strategy for future gravity
field satellite missions. 相似文献
4.
After GRACE and GOCE there will still be need and room for improvement of the knowledge (1) of the static gravity field at
spatial scales between 40 km and 100 km, and (2) of the time varying gravity field at scales smaller than 500 km. This is
shown based on the analysis of spectral signal power of various gravity field components and on the comparison with current
knowledge and expected performance of GRACE and GOCE. Both, accuracy and resolution can be improved by future dedicated gravity
satellite missions. For applications in geodesy, the spectral omission error due to the limited spatial resolution of a gravity
satellite mission is a limiting factor. The recommended strategy is to extend as far as possible the spatial resolution of
future missions, and to improve at the same time the modelling of the very small scale components using terrestrial gravity
information and topographic models.We discuss the geodetic needs in improved gravity models in the areas of precise height
systems, GNSS levelling, inertial navigation and precise orbit determination. Today global height systems with a 1 cm accuracy
are required for sea level and ocean circulation studies. This can be achieved by a future satellite mission with higher spatial
resolution in combination with improved local and regional gravity field modelling. A similar strategy could improve the very
economic method of determination of physical heights by GNSS levelling from the decimeter to the centimeter level. In inertial
vehicle navigation, in particular in sub-marine, aircraft and missile guidance, any improvement of global gravity field models
would help to improve reliability and the radius of operation. 相似文献
5.
GOCE卫星重力计划及其应用 总被引：2，自引：0，他引：2
基于CHAMP和GRACE卫星，GOCE(Gravity Field and Stead—state Ocean Circulation Explore)是欧空局(ESA)的一颗重力场和静态洋流探测卫星。利用它可得到空间分辨率为200—80km的全球重力场模型和1cm精度的大地水准面．简要介绍了目前重力卫星的发展现状与其局限性，详细叙述了GOCE卫星的组成、科学目标、测量原理、在地球物理等学科中的重要应用，并提出GOCE等重力卫星资料在我国的应用设想。 相似文献
6.
给出了轨道面接近赤道面的轨旋同步卫星的正常重力场在等势面上分布的展开式，并讨论了潮汐对其正常重力场的影响，利用这一方法，讨论了伽利略卫星正常重力场及其在等势面上的分布，以及木星的潮汐对伽利略卫星的正常重力场的影响，计算表明，潮汐对伽利略卫星的正常重力场影响不大，其径向的影响grt大约是10^-3-10^-5m/s^2的量级，与重力场在经度和纬度方向的分量接近，通过估算，月球的重力场所受到的潮汐影响要比绝大多数伽利略卫星受到的潮汐影响小。 相似文献
7.
P. Exertier 《Celestial Mechanics and Dynamical Astronomy》1993,57(1-2):137-153
The monitoring of the perturbed motion of artificial satellites since the 1960's has provided a valuable resource for improved activities in geodesy. These observations and the improved geodetic techniques they fostered have provided an unparalleled means for studying both the gravity field and the Earth's shape. In this paper, we will review the various determinations of the Earth's gravity field produced at many research centers over the years from space techniques. The specific methods which have been used to measure our planet, such as satellite altimetry and satellite orbital perturbation analyses (over short and long periods of time), will be compared. 相似文献
8.
Bert L. A. Vermeersen 《Earth, Moon, and Planets》2004,94(1-2):31-40
Examples from four main categories of solid-earth deformation processes are discussed for which the GOCE and GRACE satellite
gravity missions will not provide a high enough spatial or temporal resolution or a sufficient accuracy. Quasi-static and
episodic solid-earth deformation would benefit from a new satellite gravity mission that would provide a higher combined spatial
and temporal resolution. Seismic and core periodic motions would benefit from a new satellite mission that would be able to
detect gravity variations with a higher temporal resolution combined with very high accuracies. 相似文献
9.
The science requirements on future gravity satellite missions, following from the previous contributions of this issue, are
summarized and visualized in terms of spatial scales, temporal behaviour and accuracy. This summary serves the identification
of four classes of future satellite mission of potential interest: high-altitude monitoring, satellite-to-satellite tracking,
gradiometry, and formation flights. Within each class several variants are defined. The gravity recovery performance of each
of these ideal missions is simulated. Despite some simplifying assumptions, these error simulations result in guidelines as
to which type of mission fulfils which requirements best. 相似文献
10.
J. Flury 《Earth, Moon, and Planets》2004,94(1-2):83-91
An overview of advances in ice research which can be expected from future satellite gravity missions is given. We compare
present and expected future accuracies of the ice mass balance of Antarctica which might be constrained to 0.1–0.3 mm/year
of sea level equivalent by satellite gravity data. A key issue for the understanding of ice mass balance is the separation
of secular and interannual variations. For this aim, one would strongly benefit from longer uninterrupted time series of gravity
field variations (10 years or more). An accuracy of 0.01 mm/year for geoid time variability with a spatial resolution of 100
km would improve the separability of ice mass balance from mass change due to glacial isostatic adjustment and enable the
determination of regional variations in ice mass balance within the ice sheets. Thereby the determination of ice compaction
is critical for the exploitation of such high accuracy data. A further benefit of improved gravity field models from future
satellite missions would be the improvement of the height reference in the polar areas, which is important for the study of
coastal ice processes. Sea ice thickness determination and modelling of ice bottom topography could be improved as well. 相似文献
11.
R. Rummel 《Earth, Moon, and Planets》2004,94(1-2):103-111
Planetology serves the understanding on the one hand of the solar system and on the other hand, for investigating similarities
and differences, of our own planet. While observational evidence about the outer planets is very limited, substantial datasets
exist for the terrestrial planets. Radar and optical images and detailed models of gravity and topography give an impressive
insight into the history, composition and dynamics of moon and planets. However, there exists still significant lack of data.
It is therefore recommended to equip all future satellite missions to the moon and to planets with full tensor gravity gradiometers
and radar altimeters. 相似文献
12.
HUANG Yong HU Xiaogong HUANG Cheng 《中国科学院上海天文台年刊》2005,(1):14-21
从解析形式出发,利用月球重力场模型JGL165P1,分析了月球重力场(带谐项)对绕月低轨卫星的长期影响。为了减少计算误差,保证计算精度,在分析解中使用循环公式来计算倾角函数。结果指出对于一个高度为100km的极月轨道卫星,冻结轨道存在的可能性不大,但是当轨道倾角在i=90°附近或者高度再高一些,则有可能存在冻结轨道;对于100km高的初始圆轨道,卫星在无控的情况下半年内将会坠落到月球表面,如果高度增加到200km,则不进行轨道控制也不会坠落到月面上。利用仿真软件GEODYN解算出来的结果证实了上述结论。 相似文献
13.
利用VLBI数据确定"探测一号"卫星的轨道 总被引：5，自引：0，他引：5
双星计划的“探测一号”是中国首颗真正严格意义上的科学实验卫星,其运行轨道为中国迄今所发射的卫星中距地球最远,远地点地心距达7．8万公里．采用射电天文的VLBI技术可以对“探测一号”以及更远的深空目标,如探月飞行器实现跟踪．为了验证VLBI技术在我国探月计划中的作用,上海天文台组织了国内目前仅有的上海、乌鲁木齐和昆明3个台站对“探测一号”进行试跟踪,利用对“探测一号”约两天的VLBI观测数据,确定“探测一号”卫星的轨道,对VLBI的定轨能力做初步的探讨．按照测控部门提供的初轨 (其精度仅保证跟踪)推算的轨道与VLBI时延的拟合误差平均约2 km,时延率的拟合误差平均约15 cm／s．而利用VLBI数据定轨后的拟合程度相对于初轨有了很大的改善,结果表明,单独利用VLBI时延定轨,时延的拟合精度约5．5 m,作为外部检核的VLBI时延率的拟合精度在2 cm／s左右．单独利用VLBI时延率定轨,时延率的拟合精度约为1．3 cm／s,作为外部检核的VLBI时延的拟合精度约为29 m．而若将时延和时延率数据联合定轨,采用其内符精度加权,VLBI时延和时延率的残差分别为5．5 m和 2 cm／s．为了合理地评估VLBI定轨的真实精度,利用模拟数据进行误差协方差分析,结果表明VLBI定轨精度受动力学模型误差的影响较大,由于"探测一号”卫星的动力学模型难以精确确定,所以利用两天弧段的VLBI数据确定“探测一号”卫星轨道的位置误差为km量级,而速度误差可达cm／s量级．模拟计算还表明, VLBI和USB数据联合定轨可以大大提高定轨精度． 相似文献
14.
Efficient Determination of Global Gravity Field from Satellite-to-satellite Tracking Mission 总被引：2，自引：0，他引：2
Shin-Chan Han 《Celestial Mechanics and Dynamical Astronomy》2004,88(1):69-102
The gravity field dedicated satellite missions like CHAMP, GRACE, and GOCE are supposed to map the Earth's global gravity field with unprecedented accuracy and resolution. New models of the Earth's static and time-variable gravity fields will be available every month as one of the science products from GRACE. A method for the efficient gravity field recovery is presented using in situ satellite-to-satellite observations at altitude and results on static as well as temporal gravity field recovery are shown. Considering the energy relationship between the kinetic energy of the satellite and the gravitational potential, the disturbing potential observations can be computed from the orbital state vector, using high-low GPS tracking data, low–low satellite-to-satellite GRACE measurements, and data from 3-axis accelerometers. The solution method is based on the conjugate gradient iterative approach to efficiently recover the gravity field coefficients and approximate error covariance up to degree and order 120 every month. Based on the monthly GRACE noise-only simulation, the geoid was obtained with an accuracy of a few cm and with a resolution (half wavelength) of 160 km. However, the geoid accuracy can become worse by a factor of 6–7 because of spatial aliasing. The approximate error covariance was found to be a very good accuracy measure of the estimated coefficients, geoid, and gravity anomaly. The temporal gravity field, representing the monthly mean continental water mass redistribution, was recovered in the presence of measurement noise and high frequency temporal variation. The resulting recovered temporal gravity fields have about 0.3 mm errors in terms of geoid height with a resolution of 670 km. 相似文献
15.
J.C. Marty G. Balmino P. Rosenblatt S. Le Maistre A. Rivoldini V. Dehant T. Van Hoolst 《Planetary and Space Science》2009,57(3):350-1027
We present results of several years of research and data processing aimed at modelling the Mars gravity field and its longest wavelength time variations. The new solution includes tracking data from Mars Global Surveyor (MGS) from 1998 to 2006 (end of mission) and from Mars Odyssey from 2002 to the spring of 2008; this is the longest analyzed data set from these two orbiter missions as compared to previous works. The new model has been obtained by a team working in Europe, independently from the works of groups at NASA Jet Propulsion Laboratory (JPL) and Goddard Space Flight Center (GSFC), also with totally independent software. Observations consist in two and three-way Doppler measurements (also one way for MGS), and range tracking data collected by the Deep Space Network and have been processed in 4 day arcs, taking into account all disturbing forces of gravitational and non-gravitational origins; for each arc the state vector, drag and solar pressure model multiplying factors, and angular momentum dump parameters are adjusted. The static field (MGGM08A) is represented in spherical harmonics up to degree and order 95 and is very close to previously published models (in terms of spectral components and also over specific features); correlations with the global Mars topography are established and apparent depths of compensation by degree are derived. Lumped zonal harmonics of degree two and three are solved for every 10 days, exhibiting variations in line with previous results (including authors’ ones); the work also shows the difficulty of finding clean signatures (annual and semi-annual) for the zonal coefficient of second degree. The k2 Love number is also derived from the ensemble of data, as well as from subsets of them; values between 0.110 and 0.130 are found, which are consistent with the existence of a Martian fluid core of significant radius. 相似文献
16.
The importance of an accurate model of the Moon gravity field has been assessed for future navigation missions orbiting and/or
landing on the Moon, in order to use our natural satellite as an intermediate base for next solar system observations and
exploration as well as for lunar resources mapping and exploitation. One of the main scientific goals of MAGIA mission, whose
Phase A study has been recently funded by the Italian Space Agency (ASI), is the mapping of lunar gravitational anomalies,
and in particular those on the hidden side of the Moon, with an accuracy of 1 mGal RMS at lunar surface in the global solution
of the gravitational field up to degree and order 80. MAGIA gravimetric experiment is performed into two phases: the first
one, along which the main satellite shall perform remote sensing of the Moon surface, foresees the use of Precise Orbit Determination
(POD) data available from ground tracking of the main satellite for the determination of the long wavelength components of
gravitational field. Improvement in the accuracy of POD results are expected by the use of ISA, the Italian accelerometer
on board the main satellite. Additional gravitational data from recent missions, like Kaguya/Selene, could be used in order
to enhance the accuracy of such results. In the second phase the medium/short wavelength components of gravitational field
shall be obtained through a low-to-low (GRACE-like) Satellite-to-Satellite Tracking (SST) experiment. POD data shall be acquired
during the whole mission duration, while the SST data shall be available after the remote sensing phase, when the sub-satellite
shall be released from the main one and both satellites shall be left in a free-fall dynamics in the gravity field of the
Moon. SST range-rate data between the two satellites shall be measured through an inter-satellite link with accuracy compliant
with current state of art space qualified technology. SST processing and gravitational anomalies retrieval shall benefit from
a second ISA accelerometer on the sub-satellite in order to decouple lunar gravitational signal from other accelerations.
Experiment performance analysis shows that the stated scientific requirements can be achieved with a low mass and low cost
sub-satellite, with a SST gravimetric mission of just few months. 相似文献
17.
《Chinese Astronomy and Astrophysics》2006,30(3):318-329
The satellite “Tance 1” of the “Double-Star Program” is the first truly scientific experimentation satellite of China. Its orbit is the farthest so far launched in China, with a geocentric apogee reaching 78 thousand kilometers. The tracking of “Tance 1” and of more distant space targets, such as the lunar exploration craft, can be realized with the VLBI technique of radio astronomy. In order to test and verify the role which the VLBI technique plays in the lunar exploration program of China, Shanghai Astronomical Observatory organized the only 3 tracking stations in China (located at Shanghai, Urumqi and Kunming), to carry out test tracking of “Tance 1,” and used the time delay data obtained to determine the orbit of “Tance 1” over a two-day period, so providing a preliminary assessment of the possibility of VLBI orbit determination. The fitting error of the orbit so obtained is about 5.5 m in the time delay and about 2 cm/s in the delay rate (this for checking only), much better than is provided by the preliminary orbit (used merely for ensuring tracking) in which the corresponding figures are around 2 km and 15 cm/s. Further, if the orbit is determined by using both the time delay and time delay rate data (with weights according to their internal accuracies), then the residuals are 5.5 m in the time delay and 2 cm/s in the delay rate. For an appreciation of the true accuracy of the VLBI orbit determination, we used simulation data (of the observed two-day VLBI data) and found the results depended greatly on the error in the dynamic model of the satellite which, however, is difficult to assess, while the formal residuals are of the order of 1 kin in the delay and of cm/s in the delay rate. The simulation computation also indicates that a joint determination using both VLBI and USB data will have an improved accuracy. 相似文献
18.
In this paper, we utilize the teleparallel gravity analogs of the energy and momentum definitions of Bergmann-Thomson and
Landau-Lifshitz in order to explicitly evaluate the energy distribution (due to matter and fields including gravity) based
on the Bonnor space-time, it is shown that for a stationary beam of light, these energy-momentum definitions give the same
result. Furthermore, this result supports the viewpoint of Cooperstock and also agree with the previous works by Bringley
and Gad. 相似文献
19.
《New Astronomy》2022
We consider an equation of motion for Glashow–Weinberg–Salam model and apply the semiclassical Hamilton–Jacobi process and WKB approximation in order to compute the tunneling probability of W-bosons in the background of electromagnetic field to analyze the quantum gravity effects of charged black hole(BH) in Einstein–Gauss–Bonnet gravity theory. After this, we examine the quantum gravity influences on the generalized Lagrangian field equation. We make clear that quantum gravity effects leave the remnants on the tunneling radiation becomes non-thermal. Moreover, we analyze the graphical behavior of quantum gravity influences on corrected Hawking temperature for spin-1 particles for charged BHs. 相似文献
20.
Zhang Fei-peng Huang Cheng Feng Chu-gang Dong Xiao-jun Liao Xin-hao 《Chinese Astronomy and Astrophysics》2001,25(4):641-489
Variance component estimation (VCE) is applied to precise orbit determination (POD) of the ERS-2 satellite. Twenty 5-day long arcs in the early three months in 1998 were calculated using the SLR and PRARE data. In the data the adjacent arcs overlap for two days except the intervals for orbit maneuver. The effect of VCE orbit determination on the calculation is investigated by an analysis of residuals and comparison of overlapping arcs, and the mean a posteriori standard deviation of each group of measured residuals is given. It is shown by the residuals analysis that the fitting of the measurements is significantly improved by VCD. However, according to Abbey criterion, VCD is not able to eliminate the systematic errors due to errors in the dynamic and geometric models. The results of the comparison of the overlapping arcs show that (1) VCE reduces the mean range deviation of overlapping arcs, especially where there are obviously unreasonable deviations, so that the orbit obtained has a more uniform precision; (2) By using VCE, adjacent arcs tend to close up and this is more apparent in the transverse direction. From the mean a posteriori standard error of each group of measurements, it can be seen that as far as the single normal point measurement is concerned, the data of some SLR stations are more important than other measurements in POD calculation. Generally speaking, determination of weighting by using VCE is more reasonable than by using initial standard deviation. 相似文献