Intersatellite range monitoring using optical interferometry

Pierce, R. M.; Leitch, James; Stephens, M.; Bender, P. L.; Nerem, R. S.

doi:10.1364/ao.47.005007

Cited by 51 publications

(31 citation statements)

References 8 publications

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“…Second, it might be helpful in designing GRACE follow-on missions. Investigations of the optimal design of such a mission started a few years ago Pierce et al 2008;van Dam et al 2008;Wiese et al 2009) and have become, by this moment, the focus of research efforts of numerous groups worldwide. The key element of such researches is assessing the performance of various mission scenarios.…”

Section: Introductionmentioning

confidence: 99%

Understanding data noise in gravity field recovery on the basis of inter-satellite ranging measurements acquired by the satellite gravimetry mission GRACE

Ditmar

Encarnação

Farahani

2011

J Geod

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Spectral analysis of data noise is performed in the context of gravity field recovery from inter-satellite ranging measurements acquired by the satellite gravimetry mission GRACE. The motivation of the study is two-fold: (i) to promote a further improvement of GRACE data processing techniques and (ii) to assist designing GRACE follow-on missions. The analyzed noise realizations are produced as the difference between the actual GRACE inter-satellite range measurements and the predictions based on state-of-the-art force models. The exploited functional model is based on the so-called "range combinations," which can be understood as a finite-difference analog of inter-satellite accelerations projected onto the line-of-sight connecting the satellites. It is shown that low-frequency noise is caused by limited accuracy of the computed GRACE orbits. In the first instance, it leads to an inaccurate estimation of the radial component of the inter-satellite velocities. A large impact of this component stems from the fact that it is directly related to centrifugal accelerations, which have to be taken into account when the measured range-accelerations are linked with inter-satellite accelerations. Another effect of orbit inaccuracies is a miscalculation of forces acting on the satellites (particularly, the one described by the zero-degree term of the Earth's gravitational field). The major contributors to the noise budget at high frequencies (above 9 mHz) are (i) ranging sensor errors and (ii) limited knowledge of the Earth's static gravity field at high degrees. Importantly, we show that updating the model of the static field on the basis of the available data must be performed with a caution as the result may not be physical due to a non-unique recovery of high-degree coefficients. The source of noise in the range of intermediate frequencies (1-9 mHz), which is particularly critical for an accurate gravity field recovery, is not fully understood yet. We show, however, that it cannot be explained by inaccuracies in background models of time-varying gravity field. It is stressed that most of the obtained results can be treated as sufficiently general (i.e., applicable in the context of a statistically optimal estimation based on any functional model).

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Section: Introductionmentioning

confidence: 99%

Understanding data noise in gravity field recovery on the basis of inter-satellite ranging measurements acquired by the satellite gravimetry mission GRACE

Ditmar

Encarnação

Farahani

2011

J Geod

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“…The future missions, such as the Beyond Einstein Advanced Coherent Optical Network (BEACON) [61] or the GRACE Follow-On (GRACE-FO) mission [62], will probe the gravitational field of the Earth with unprecedented accuracy. The BEACON mission will employ four small spacecraft equipped with laser transceivers and the spacecraft will be placed in a circular Earth orbit at a radius of 80,000 km.…”

Section: Discussionmentioning

confidence: 99%

Influences of dark energy and dark matter on gravitational time advancement

Ghosh

Bhadra

2015

Eur. Phys. J. C

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The effect of dark matter/energy on the gravitational time advancement (negative effective time delay) has been investigated considering a few dark energy/matter models including cosmological constant. It is found that dark energy gives only a (positive) gravitational time delay, irrespective of the position of the observer, whereas a pure Schwarzschild geometry leads to a gravitational time advancement when the observer is situated at a relatively stronger gravitational field point in the light trajectory. Consequently, there will be no time advancement effect at all at radial distances where the gravitational field due to dark energy is stronger than the gravitational field of the Schwarzschild geometry.

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“…The interferometer produces the phase difference and frequency observables from which the range and range rate between the two spacecraft are deduced. These time series of phase and frequency values constitute the set of LRI observables of GRACE-FO [1,2].…”

Section: A Relativistic Clock Synchronization and The Geodesic Signamentioning

confidence: 99%

“…Phase locking in the transponder is expected to eliminate transponder laser frequency noise, leaving the transmitter laser frequency noise and phase noise due to pointing errors, experimental features that are captured in the instrument design [1,2], as the two major noise sources.…”

Section: Introductionmentioning

confidence: 99%

General relativistic laser interferometric observables of the GRACE-Follow-On mission

2014

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We develop a high-precision model for laser ranging interferometric (LRI) observables of the GRACE Follow-On (GRACE-FO) mission. For this, we study the propagation of an electromagnetic wave in the gravitational field in the vicinity of an extended body, in the post-Newtonian approximation of the general theory of relativity. We present a general relativistic model for the phase of a plane wave that accounts for contributions of all the multipoles of the gravitating body, its angular momentum, as well as the contribution of tidal fields produced by external sources. We develop a new approach to model a coherent signal transmission in the gravitational field of the solar system that relies on a relativistic treatment of the phase. We use this approach to describe high-precision interferometric measurements on GRACE-FO and formulate the key LRI observables, namely the phase and phase rate of a coherent laser link between the two spacecraft. We develop a relativistic model for the LRI-enabled range between the two GRACE-FO spacecraft, accurate to less than 1 nm, and a high-precision model for the corresponding range rate, accurate to better than 0.1 nm/s. We also formulate high-precision relativistic models for the double one-way range (DOWR) and DOWR-enabled range rate observables originally used on GRACE and now studied for interferometric measurements on GRACE-FO. Our formulation justifies the basic assumptions behind the design of the GRACE-FO mission and highlights the importance of achieving nearly circular and nearly identical orbits for the GRACE-FO spacecraft.

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Intersatellite range monitoring using optical interferometry

Cited by 51 publications

References 8 publications

Understanding data noise in gravity field recovery on the basis of inter-satellite ranging measurements acquired by the satellite gravimetry mission GRACE

Understanding data noise in gravity field recovery on the basis of inter-satellite ranging measurements acquired by the satellite gravimetry mission GRACE

Influences of dark energy and dark matter on gravitational time advancement

General relativistic laser interferometric observables of the GRACE-Follow-On mission

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