Mon Feb 16, F. Flechtner
• Sorted by Date • Sorted by Last Name of First Author •
Zhong, Shengjian, Wang, Xiaoya, Li, Min, Wang, Jungang, Luo, Peng, Li, Yabo, and Zhou, Houxiang, 2026. GRACE–FO Real–Time Precise Orbit Determination Using Onboard GPS and Inter–Satellite Ranging Measurements with Quality Control Strategy. Remote Sensing, 18(2):351, doi:10.3390/rs18020351.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2026RemS...18..351Z,
author = {{Zhong}, Shengjian and {Wang}, Xiaoya and {Li}, Min and {Wang}, Jungang and {Luo}, Peng and {Li}, Yabo and {Zhou}, Houxiang},
title = "{GRACE-FO Real-Time Precise Orbit Determination Using Onboard GPS and Inter-Satellite Ranging Measurements with Quality Control Strategy}",
journal = {Remote Sensing},
keywords = {GRACE-FO, inter-satellite link, extended Kalman filter, real-time precise orbit determination, quality control},
year = 2026,
month = jan,
volume = {18},
number = {2},
eid = {351},
pages = {351},
abstract = "{What are the main findings? Robustness of the quality control strategy:
The adopted iterative quality control method based on post-fit
residuals effectively suppresses GNSS observation noise and
outliers, thereby significantly improving the stability of the
filter and the orbit accuracy. Efficacy of inter-satellite range
measurements in asymmetric conditions: The experiment verifies
that the inclusion of inter-satellite range measurements yields
substantial accuracy improvements for GRACE-FO under asymmetric
observation conditions. This is particularly decisive for the
satellite with poor data quality (GRACE-D), where orbit accuracy
was improved by 39\%, effectively recovering its performance to
the level of GRACE-C. Robustness of the quality control
strategy: The adopted iterative quality control method based on
post-fit residuals effectively suppresses GNSS observation noise
and outliers, thereby significantly improving the stability of
the filter and the orbit accuracy. Efficacy of inter-satellite
range measurements in asymmetric conditions: The experiment
verifies that the inclusion of inter-satellite range
measurements yields substantial accuracy improvements for GRACE-
FO under asymmetric observation conditions. This is particularly
decisive for the satellite with poor data quality (GRACE-D),
where orbit accuracy was improved by 39\%, effectively
recovering its performance to the level of GRACE-C. What are the
implications of the main findings? Stabilization of
constellation geometry: The integration of inter-satellite range
measurements effectively compensates for geometric deficiencies
in LEO satellite observations, thereby guaranteeing the
structural stability of formation flying or large-scale
constellations even when individual nodes are degraded.
Spatiotemporal reference transfer and formation stability: High-
precision ISLs serve as a critical conduit for transferring
spatiotemporal references within the constellation. By
establishing rigid geometric constraints, precise state
information from satellites with normal data quality is
effectively propagated to constrain degraded satellites.
Stabilization of constellation geometry: The integration of
inter-satellite range measurements effectively compensates for
geometric deficiencies in LEO satellite observations, thereby
guaranteeing the structural stability of formation flying or
large-scale constellations even when individual nodes are
degraded. Spatiotemporal reference transfer and formation
stability: High-precision ISLs serve as a critical conduit for
transferring spatiotemporal references within the constellation.
By establishing rigid geometric constraints, precise state
information from satellites with normal data quality is
effectively propagated to constrain degraded satellites. Real-
Time Precise Orbit Determination (RTPOD) of Low Earth Orbit
(LEO) satellites relies primarily on onboard GNSS observations
and may suffer from degraded performance when observation
geometry weakens or tracking conditions deteriorate within
satellite formations. To enhance the robustness and accuracy of
RTPOD under such conditions, a cooperative Extended Kalman
Filter (EKF) framework that fuses onboard GNSS and inter-
satellite link (ISL) range measurements is established,
integrated with an iterative Detection, Identification, and
Adaptation (DIA) quality control algorithm. By introducing high-
precision ISL range measurements, the strategy increases
observation redundancy, improves the effective observation
geometry, and provides strong relative position constraints
among LEO satellites. This constraint strengthens solution
stability and convergence, while simultaneously enhancing the
sensitivity of the DIA-based quality control to observation
outliers. The proposed strategy is validated in a simulated
real-time environment using Centre National d'Etudes Spatiales
(CNES) real-time products and onboard observations of the GRACE-
FO mission. The results demonstrate comprehensive performance
enhancements for both satellites over the experimental period.
For the GRACE-D satellite, which suffers from about 17\% data
loss and a cycle slip ratio several times higher than that of
GRACE-C, the mean orbit accuracy improves by 39\% (from 13.1 cm
to 8.0 cm), and the average convergence time is shortened by
44.3\%. In comparison, the GRACE-C satellite achieves a 4.2\%
mean accuracy refinement and a 1.3\% reduction in convergence
time. These findings reveal a cooperative stabilization
mechanism, where the high-precision spatiotemporal reference is
transferred from the robust node to the degraded node via inter-
satellite range measurements. This study demonstrates the
effectiveness of the proposed method in enhancing the robustness
and stability of formation orbit determination and provides
algorithmic validation for future RTPOD of LEO satellite
formations or large-scale constellations.}",
doi = {10.3390/rs18020351},
adsurl = {https://ui.adsabs.harvard.edu/abs/2026RemS...18..351Z},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
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GRACE-FO
Mon Feb 16, F. Flechtner