A 1% Measurement of the Gravitomagnetic Field of the Earth with Laser-Tracked Satellites

A new measurement of the gravitomagnetic field of the Earth is presented. The measurement has been obtained through the careful evaluation of the Lense-Thirring (LT) precession on the combined orbits of three passive geodetic satellites, LAGEOS, LAGEOS II, and LARES, tracked by the Satellite Laser Ranging (SLR) technique. This general relativity precession, also known as frame-dragging, is a manifestation of spacetime curvature generated by mass-currents, a peculiarity of Einstein’s theory of gravitation. The measurement stands out, compared to previous measurements in the same context, for its precision (≃7.4×10−3, at a 95% confidence level) and accuracy (≃16×10−3), i.e., for a reliable and robust evaluation of the systematic sources of error due to both gravitational and non-gravitational perturbations. To achieve this measurement, we have largely exploited the results of the GRACE (Gravity Recovery And Climate Experiment) mission in order to significantly improve the description of the Earth’s gravitational field, also modeling its dependence on time. In this way, we strongly reduced the systematic errors due to the uncertainty in the knowledge of the Earth even zonal harmonics and, at the same time, avoided a possible bias of the final result and, consequently, of the precision of the measurement, linked to a non-reliable handling of the unmodeled and mismodeled periodic effects.

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Equivalence principle for massive bodies in a generalized theory of gravitation. II

Canadian Journal of Physics ◽

10.1139/p82-209 ◽

1982 ◽

Vol 60 (11) ◽

pp. 1556-1560 ◽

Cited By ~ 4

Author(s):

J. C. McDow ◽

J. W. Moffat

Keyword(s):

Equivalence Principle ◽

Equations Of Motion ◽

Upper Bounds ◽

Laser Ranging ◽

Coordinate Frame ◽

Lunar Laser Ranging ◽

The Earth ◽

Lunar Laser ◽

Theory Of Gravitation ◽

Three Body

The three-body equations of motion are examined for periodic perturbations in an earth centered coordinate frame. The lunar-laser-ranging data is then used to place upper bounds on the new l parameters associated with the earth and sun.

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Intercomparison of Lunar Laser and Traditional Determinations of Earth Rotation

International Astronomical Union Colloquium ◽

10.1017/s0252921100002463 ◽

1981 ◽

Vol 63 ◽

pp. 53-88 ◽

Cited By ~ 1

Author(s):

H. F. Fliegel ◽

J. O. Dickey ◽

J. G. Williams

Keyword(s):

Earth Rotation ◽

Smooth Curve ◽

Systematic Errors ◽

Polar Coordinates ◽

Laser Ranging ◽

Lunar Laser Ranging ◽

The Earth ◽

Lunar Laser ◽

Rotational Orientation ◽

The Difference

AbstractThe rotational orientation of the earth (UTO at McDonald Observatory) has been determined from lunar laser ranging (LLR) measurements for the interval 1971 to 1980. The results have been differenced from those obtained by conventional means as published by the Bureau International de l’Heure (BIH), on its 1979 system. The difference displays a quasi-seasonal signature, which we ascribe to systematic errors in the conventional measurements. The lunar data are well represented by a smooth curve, which gives UTO at McDonald with a precision of about 3/4 milliseconds or better, and UT1 to within 1 millisecond using BIH polar coordinates.

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WILL IT BE POSSIBLE TO MEASURE INTRINSIC GRAVITOMAGNETISM WITH LUNAR LASER RANGING?

International Journal of Modern Physics D ◽

10.1142/s0218271809015114 ◽

2009 ◽

Vol 18 (08) ◽

pp. 1319-1326 ◽

Cited By ~ 2

Author(s):

LORENZO IORIO

Keyword(s):

Orbital Motion ◽

Radial Component ◽

Laser Ranging ◽

The Moon ◽

Lunar Laser Ranging ◽

The Earth ◽

Gravitomagnetic Field ◽

Lunar Laser ◽

Short Period ◽

Orbital Revolution

In this paper we mainly explore the possibility of measuring the action of the intrinsic gravitomagnetic field of the rotating Earth on the orbital motion of the Moon with the lunar laser ranging (LLR) technique. Expected improvements in it should push the precision in measuring the Earth–Moon range to the mm level; the present-day root mean square (RMS) accuracy in reconstructing the radial component of the lunar orbit is about 2 cm; its harmonic terms can be determined at the mm level. The current uncertainty in measuring the lunar precession rates is about 10-1 milliarcseconds per year. The Lense–Thirring secular — i.e. averaged over one orbital period — precessions of the node and the perigee of the Moon induced by the Earth's spin angular momentum amount to 10-3 milliarcseconds per year, yielding transverse and normal shifts of 10-1-10-2 cm yr-1. In the radial direction there is only a short-period — i.e. nonaveraged over one orbital revolution — oscillation with an amplitude of 10-5 m. Major limitations come also from some systematic errors induced by orbital perturbations of classical origin, such as the secular precessions induced by the Sun and the oblateness of the Moon, whose mismodeled parts are several times larger than the Lense–Thirring signal. The present analysis holds also for the Lue–Starkman perigee precession due to the multidimensional braneworld model by Dvali, Gabadadze and Porrati (DGP); indeed, it amounts to about 5 × 10-3 milliarcseconds per year.

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Satellites testing general relativity: Residuals versus perturbations

International Journal of Modern Physics D ◽

10.1142/s0218271817410206 ◽

2017 ◽

Vol 26 (05) ◽

pp. 1741020 ◽

Cited By ~ 5

Author(s):

V. G. Gurzadyan ◽

I. Ciufolini ◽

A. Paolozzi ◽

A. L. Kashin ◽

H. G. Khachatryan ◽

...

Keyword(s):

General Relativity ◽

Laser Ranging ◽

Frame Dragging ◽

Yarkovsky Effect ◽

Earth Gravity ◽

The Earth ◽

Earth Gravity Model ◽

Grace Satellite ◽

Precision Testing

Laser ranging satellites have proved their efficiency for high precision testing of the effect of frame-dragging, one of the remarkable predictions of General Relativity. The analysis of the randomness properties of the residuals of LAGEOS and LAGEOS 2 satellites reveals the role of the thermal thrust — Yarkovsky effect — on the satellite which was in the orbit for longer period (LAGEOS). We also compute Earth’s tidal modes affecting the satellite LARES. The recently obtained 5% accuracy limit reached for the frame dragging effect based on the 3.5 year data of LARES analyzed together with those of LAGEOS satellites and using the Earth gravity model of GRACE satellite, is also represented.

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Processing of GRACE-FO satellite-to-satellite tracking data using the GRACE-SIGMA software

10.5194/egusphere-egu2020-20851 ◽

2020 ◽

Author(s):

Igor Koch ◽

Mathias Duwe ◽

Jakob Flury ◽

Akbar Shabanloui

Keyword(s):

Laser Ranging ◽

Satellite Measurements ◽

Satellite Mission ◽

The Earth ◽

Gravity Fields ◽

Data Products ◽

Level 1 ◽

Orbit Types ◽

Gravity Recovery

The dual-satellite mission GRACE Follow-On (GRACE-FO) was launched in May 2018 as the successor of the Gravity Recovery And Climate Experiment (GRACE).&#160;In May 2019 first level 1 data products were made available to the community and are now published regularly.&#160;These products, among others, include orbits, accelerometer measurements, star camera data and micron and sub-micron precise inter-satellite range measurements.&#160;The data products are used by different groups to compute estimates of monthly gravity fields of the Earth.&#160;The in-house developed GRACE-SIGMA software is used at the Institut of Geodesy/Leibniz University Hannover for the estimation of monthly gravity fields.&#160;Several parts of the software&#8217;s processing chain, such as background modeling, were updated recently and different parametrization scenarios were tested.&#160;First solutions were estimated based on laser ranging interferometer measurements.&#160;Moreover, different orbit types, such as reduced-dynamic and kinematic, were tested.&#160;In this contribution, we present the influence of these updates and tests on the quality of the gravity fields.&#160;The obtained solutions are assessed in terms of error degree standard deviations and post-fit residuals of the inter-satellite measurements.

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General Relativity Measurements in the Field of Earth with Laser-Ranged Satellites: State of the Art and Perspectives

Universe ◽

10.3390/universe5060141 ◽

2019 ◽

Vol 5 (6) ◽

pp. 141 ◽

Cited By ~ 8

Author(s):

David Lucchesi ◽

Luciano Anselmo ◽

Massimo Bassan ◽

Carmelo Magnafico ◽

Carmen Pardini ◽

...

Keyword(s):

Gravitational Field ◽

Relativistic Effect ◽

State Of The Art ◽

Systematic Errors ◽

Gravitational Perturbations ◽

Zonal Harmonics ◽

The Earth ◽

Temporal Models ◽

New Models

Recent results of the LARASE research program in terms of model improvements and relativistic measurements are presented. In particular, the results regarding the development of new models for the non-gravitational perturbations that affect the orbit of the LAGEOS and LARES satellites are described and discussed. These are subtle and complex effects that need a deep knowledge of the structure and the physical characteristics of the satellites in order to be correctly accounted for. In the field of gravitational measurements, we present a new measurement of the relativistic Lense-Thirring precession with a 0.5 % precision. In this measurement, together with the relativistic effect we also estimated two even zonal harmonics coefficients. The uncertainties of the even zonal harmonics of the gravitational field of the Earth have been responsible, until now, of the larger systematic uncertainty in the error budget of this kind of measurements. For this reason, the role of the errors related to the model used for the gravitational field of the Earth in these measurements is discussed. In particular, emphasis is given to GRACE temporal models, that strongly help to reduce this kind of systematic errors.

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Effect of non-tidal station loading on Lunar Laser Ranging observatories and on the estimation of Earth orientation parameters

10.5194/egusphere-egu21-7827 ◽

2021 ◽

Author(s):

Vishwa Vijay Singh ◽

Liliane Biskupek ◽

Jürgen Müller ◽

Mingyue Zhang

Keyword(s):

Research Centre ◽

Laser Ranging ◽

The Moon ◽

Lunar Laser Ranging ◽

Earth Orientation Parameters ◽

Tidal Station ◽

Earth Orientation ◽

The Earth ◽

Lunar Laser ◽

Orientation Parameters

The distance between the observatories on Earth and the retro-reflectors on the Moon has been regularly observed by the Lunar Laser Ranging (LLR) experiment since 1970. In the recent years, observations with bigger telescopes (APOLLO) and at infra-red wavelength (OCA) are carried out, resulting in a better distribution of precise LLR data over the lunar orbit and the observed retro-reflectors on the Moon, and a higher number of LLR observations in total. Providing the longest time series of any space geodetic technique for studying the Earth-Moon dynamics, LLR can also support the estimation of Earth orientation parameters (EOP), like UT1. The increased number of highly accurate LLR observations enables a more accurate estimation of the EOP. In this study, we add the effect of non-tidal station loading (NTSL) in the analysis of the LLR data, and determine post-fit residuals and EOP. The non-tidal loading datasets provided by the German Research Centre for Geosciences (GFZ), the International Mass Loading Service (IMLS), and the EOST loading service of University of Strasbourg in France are included as corrections to the coordinates of the LLR observatories, in addition to the standard corrections suggested by the International Earth Rotation and Reference Systems Service (IERS) 2010 conventions. The Earth surface deforms up to the centimetre level due to the effect of NTSL. By considering this effect in the Institute of Geodesy (IfE) LLR model (called &#8216;LUNAR&#8217;), we obtain a change in the uncertainties of the estimated station coordinates resulting in an up to 1% improvement, an improvement in the post-fit LLR residuals of up to 9%, and a decrease in the power of the annual signal in the LLR post-fit residuals of up to 57%. In a second part of the study, we investigate whether the modelling of NTSL leads to an improvement in the determination of EOP from LLR data. Recent results will be presented.

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Preliminary monthly gravity field models from kinematic orbits of SWARM Satellites

10.5194/egusphere-egu21-9839 ◽

2021 ◽

Author(s):

Xingfu Zhang ◽

Qiujie Chen ◽

Yunzhong Shen

Keyword(s):

Gravity Field ◽

Large Scale ◽

Earth System ◽

The Earth ◽

Swarm Satellites ◽

Variable Gravity ◽

Data Gap ◽

One Year ◽

Gravity Recovery ◽

Gravity Field Models

&#160; &#160; &#160; Although the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE FO) satellite missions play an important role in monitoring global mass changes within the Earth system, there is a data gap of about one year spanning July 2017 to May 2018, which leads to discontinuous gravity observations for monitoring global mass changes. As an alternative mission, the SWARM satellites can provide gravity observations to close this data gap. In this paper, we are dedicated to developing alternative monthly time-variable gravity field solutions from SWARM data. Using kinematic orbits of SWARM from ITSG for the period January 2015 to September 2020, we have generated a preliminary time series of monthly gravity field models named Tongji-Swarm2019 up to degree and order 60. The comparisons between Tongji-Swarm2019 and GRACE/GRACE-FO monthly solutions show that Tongji-Swarm2019 solutions agree with GRACE/GRACE-FO models in terms of large-scale mass change signals over amazon, Greenland and other regions. We can conclude that Tongji-Swarm2019 monthly gravity field models are able to close the gap between GRACE and GRACE FO.

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Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type

Artificial Satellites ◽

10.2478/arsa-2020-0008 ◽

2020 ◽

Vol 55 (3) ◽

pp. 100-117

Author(s):

Viktor Szabó ◽

Dorota Marjańska

Keyword(s):

Gravity Field ◽

Ocean Circulation ◽

Gravity Data ◽

The Other ◽

Subsurface Water ◽

Satellite Gravity ◽

Absolute Gravimetry ◽

The Earth ◽

Gravity Measurements ◽

Gravity Recovery

AbstractGlobal satellite gravity measurements provide unique information regarding gravity field distribution and its variability on the Earth. The main cause of gravity changes is the mass transportation within the Earth, appearing as, e.g. dynamic fluctuations in hydrology, glaciology, oceanology, meteorology and the lithosphere. This phenomenon has become more comprehensible thanks to the dedicated gravimetric missions such as Gravity Recovery and Climate Experiment (GRACE), Challenging Minisatellite Payload (CHAMP) and Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). From among these missions, GRACE seems to be the most dominating source of gravity data, sharing a unique set of observations from over 15 years. The results of this experiment are often of interest to geodesists and geophysicists due to its high compatibility with the other methods of gravity measurements, especially absolute gravimetry. Direct validation of gravity field solutions is crucial as it can provide conclusions concerning forecasts of subsurface water changes. The aim of this work is to present the issue of selection of filtration parameters for monthly gravity field solutions in RL06 and RL05 releases and then to compare them to a time series of absolute gravimetric data conducted in quasi-monthly measurements in Astro-Geodetic Observatory in Józefosław (Poland). The other purpose of this study is to estimate the accuracy of GRACE temporal solutions in comparison with absolute terrestrial gravimetry data and making an attempt to indicate the significance of differences between solutions using various types of filtration (DDK, Gaussian) from selected research centres.

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Assessment of GRACE-FO Laser Ranging Interferometer measurements

10.5194/egusphere-egu21-1249 ◽

2021 ◽

Author(s):

Athina Peidou ◽

Felix Landerer ◽

David Wiese ◽

Matthias Ellmer ◽

Eugene Fahnestock ◽

...

Keyword(s):

High Frequency ◽

Signal To Noise Ratio ◽

Small Scale ◽

Laser Ranging ◽

High Signal ◽

Measurement Sensitivity ◽

One Year ◽

Mass Transfers ◽

Gravity Recovery ◽

System Errors

The performance of Gravity Recovery and Climate Experiment Follow&#8208;On (GRACE-FO) laser ranging interferometer (LRI) system is assessed in both space and frequency domains. With LRI&#8217;s measurement sensitivity being as small as 0.05 nm/s2 at GRACE-FO altitude we perform a thorough assessment on the ability of the instrument to detect real small-scale high-frequency gravity signals. Analysis of range acceleration measurements along the orbit for nearly one year of daily solutions suggests that LRI can detect signals induced by mass perturbation up to 26 mHz, i.e., ~145 km spatial resolution. Additionally, high frequency signals that are not adequately modeled by dealiasing models are clearly detected and their magnitude is shown to reach 2-3 nm/s2. The alternative K&#8208;band microwave ranging system (KBR) is also examined and results demonstrate the inability of KBR to retrieve signals above 15mHz (i.e., shorter than ~200 km) as the noise of the KBR range acceleration increases rapidly. Overall, the first stream of LRI measurements shows that the high signal to noise ratio allows for detection of mass transfers in finer scales, however the ability to fully exploit the high-quality signal measured by the LRI in Level 2 products is still constrained by noise of background models and other onboard instrumentation and measurement system errors.Copyright Acknowledgment: This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Science Program.

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