Instrument data simulations for GRACE  Follow-on: observation and noise models

Darbeheshti, Neda; Wegener, Henry; Müller, Vitali; Naeimi, Majid; Heinzel, Gerhard; Hewitson, M.

doi:10.5194/essd-9-833-2017

Cited by 14 publications

(10 citation statements)

References 12 publications

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“…Since the noise floor of the assumed quantum instrumentation is nearly four orders of magnitude lower than that of GRACE-FO (Darbeheshti et al, 2017), also the resulting productonly errors are about four orders of magnitude smaller (compare to Flechtner et al, 2016).…”

Section: Product-only Simulation Resultsmentioning

confidence: 99%

Constellation design and performance of future quantum satellite gravity missions

Zingerle,

Pail,

Gruber

et al. 2024

Preprint

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Temporal aliasing is currently the largest error contributor to time-variable satellite gravity field models. Therefore, the evolution of sensor technologies has to be complemented by strategies to reduce temporal aliasing errors. The most straightforward way to improve temporal aliasing are extended satellite constellations, because they improve the observation geometry and increase the achievable temporal resolution. Therefore, strategies to optimize the design of larger satellite constellations are investigated in this contribution. A complete constellation modelling procedure is presented starting from primary design variables (such as the required targeted resolutions) and concluding with concrete orbital elements for the individual satellites. In parallel, it is evaluated if improved instrument sensitivities based on quantum technologies (cold atom interferometry) can be fully exploited in the case of larger constellations. For this, future quantum satellite gravity missions adopting the gradiometry concept (similar to the GOCE mission) and the low-low satellite-to-satellite tracking concept (similar to GRACE/-FO) are simulated on optimized constellations with up to 6 satellites/pairs. The retrieval performance of a 6-pair mission in terms of the global equivalent water height RMS can be improved by a factor of roughly 3 compared to an inclined double-pair mission. 3D-gradiometry has intrinsically a better de-aliasing behavior but has extremely high accuracy requirements for the gradiometer (about 10 µEotvos) and the attitude reconstruction to be of any benefit. All simulations show that also when incorporating improved sensor technologies such as future quantum sensing instruments in extended constellations, temporal aliasing will remain the dominant error source by far, up to five orders of magnitude larger than the instrument errors. Therefore, improving sensor technologies has to go hand in hand with larger satellite constellations together with improved space-time parameterization strategies to further reduce temporal aliasing effects.

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Section: Product-only Simulation Resultsmentioning

confidence: 99%

Constellation design and performance of future quantum satellite gravity missions

Zingerle,

Pail,

Gruber

et al. 2024

Preprint

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“…The main influencing factors of MWR measurement accuracy are time delay stability of radio frequency (RF) channel, antenna phase center stability, multipath error, ionospheric delay error, USO phase noise, time-tag error, system noise, etc., and two error sources mainly related to the platform design of the satellite [ 25 ]: Time delay stability of RF channel and stability of antenna phase center, a crucial segment to ensure the high precision of measurement of the MWR system, which are mainly affected by the temperature stability. Since the MWR system measures inter-satellite distance change and its rate, there is no strict requirement for equipment absolute time delay, but it requires equipment to have high delay stability, including stability of antenna phase center and time delay stability of RF channel.…”

Section: Earth’s Gravity Field Detection Mission and Payloadsmentioning

confidence: 99%

“…Application of a laser interferometric technique can be found in the LISA-Pathfinder mission, launched in December 2015, lead by NASA and ESA [ 17 , 18 , 19 ], and GRACE follow-on mission, launched in May 2018 [ 20 , 21 , 22 , 23 ]. At the same time, a microwave radio based ranging technique is also widely used in space, and even functioned as the primary ranging payload in real observing missions [ 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Precise Microwave Ranging Technology for Low Earth Orbit Formation Missions with Beidou Time-Synchronize Receiver

Wang

Gong

et al. 2021

Sensors

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In this study, submillimeter level accuracy K-band microwave ranging (MWR) equipment is demonstrated, aiming to verify the detection of the Earth’s gravity field (EGF) and digital elevation models (DEM), through spacecraft formation flying (SFF) in low Earth orbit (LEO).In particular, this paper introduces in detail an integrated BeiDou III B1C/B2a dual frequency receiver we designed and developed, including signal processing scheme, gain allocation, and frequency planning. The receiver matched the 0.1 ns precise synchronize time-frequency benchmark for the MWR system, verified by a static and dynamic test, compared with a time interval counter synchronization solution. Moreover, MWR equipment ranging accuracy is explored in-depth by using different ranging techniques. The test results show that MWR achieved 40 μm and 1.6 μm/s accuracy for ranging and range rate during tests, using synchronous dual one-way ranging (DOWR) microwave phase accumulation frame, and 6 μm/s range rate accuracy obtained through a one-way ranging experiment. The ranging error sources of the whole MWR system in-orbit are analyzed, while the relative orbit dynamic models, for formation scenes, and adaptive Kalman filter algorithms, for SFF relative navigation designs, are introduced. The performance of SFF relative navigation using MWR are tested in a hardware in loop (HIL) simulation system within a high precision six degree of freedom (6-DOF) moving platform. The final estimation error from adaptive relative navigation system using MWR are about 0.42 mm (range/RMS) and 0.87 μm/s (range rate/RMS), which demonstrated the promising accuracy for future applications of EGF and DEM formation missions in space.

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“…For comparison, Fig. 7 also shows a model of LRI laser frequency noise derived from ground measurements and ACC noise based on a model for GRACE [31], converted to line-of-sight range. Noise in the ACC data is one of the error contributors in gravity field recovery.…”

Section: Parameter Estimation a Ttl Modelmentioning

confidence: 99%

Tilt-to-Length Coupling in the GRACE Follow-On Laser Ranging Interferometer

Wegener

Müller

Heinzel

et al. 2020

Journal of Spacecraft and Rockets

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The Laser Ranging Interferometer onboard the Gravity Recovery and Climate Experiment Follow-On satellites is the first laser interferometer in space measuring satellite-to-satellite distance variations. One of its main noise sources at low frequencies is the so-called tilt-to-length coupling, caused by satellite pointing variations. This error is estimated by fitting a linear coupling model, making use of the so-called center-of-mass calibration maneuvers. These maneuvers are performed regularly for the original purpose of center-of-mass determination. Here, the results of the tilt-to-length estimations for the Laser Ranging Interferometer are presented in terms of coupling factors, which are all within 200 μm ⋅ rad −1 and thus meet the requirements. From these parameters, estimations of nadir and cross-track components of the spacecraft center-of-mass positions with respect to the interferometer reference point are derived, providing an additional method to track center-of-mass movement over time.Nomenclature p = spacecraft positions, m q = spacecraft attitude quaternions X = spacecraft state vector θ = intersatellite pointing angles, rad λ = tilt-to-length coupling factors, m ⋅ rad −1 ρ = intersatellite range, m ω = spacecraft angular velocities, rad ⋅ s −1

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Instrument data simulations for GRACE Follow-on: observation and noise models

Cited by 14 publications

References 12 publications

Constellation design and performance of future quantum satellite gravity missions

Constellation design and performance of future quantum satellite gravity missions

Evaluation of Precise Microwave Ranging Technology for Low Earth Orbit Formation Missions with Beidou Time-Synchronize Receiver

Tilt-to-Length Coupling in the GRACE Follow-On Laser Ranging Interferometer

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