Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained
Low Earth Orbit (LEO) satellites can augment the traditional GNSS-based positioning, navigation and timing services, which require real-time high-precision LEO satellite clock products. As the complicated systematic efects contained in the LEO satellite clock estimates limit their high-precision...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Published: |
Springer Nature
2024
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| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/DP240101710 http://hdl.handle.net/20.500.11937/95660 |
| _version_ | 1848766040871272448 |
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| author | Xie, Wei Su, Hang Wang, Kan Liu, Jiawei El-Mowafy, Ahmed Yang, Xuhai |
| author_facet | Xie, Wei Su, Hang Wang, Kan Liu, Jiawei El-Mowafy, Ahmed Yang, Xuhai |
| author_sort | Xie, Wei |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Low Earth Orbit (LEO) satellites can augment the traditional GNSS-based positioning, navigation and timing services,
which require real-time high-precision LEO satellite clock products. As the complicated systematic efects contained in the
LEO satellite clock estimates limit their high-precision mid- to long-term prediction, high-frequency LEO satellite clocks
need to be estimated within a Kalman flter, resulting in a short prediction time for real-time applications. Compared to the
clock estimation using Batch Least-Squares (BLS) adjustment, flter-based clock estimation experiences a lower precision.
Increasing the model strength by introducing external orbital information, thus, de-correlating the orbital and clock param eters, will beneft real-time clock precision. In this contribution, reduced-dynamic LEO satellite orbits are frst estimated
using BLS adjustment in near real-time and predicted in the short term. The predicted orbits are then constrained during the
Kalman-flter-based clock estimation process. The variance–covariance matrix of the introduced orbital errors is tested for
diferent sets of values in the radial, along-track and cross-track directions when constraining orbits of diferent prediction
times. One week of GPS data from the Sentinel-3B satellite in 2018 was used for validation of the proposed method. When
weakly constraining high-accuracy predicted orbits within a prediction time of 20 min, i.e., with a standard deviation of the
constraint set to 2–3 dm in the radial and cross-track directions, and 4–6 dm in the along-track direction, the estimated clock
accuracy can be improved from about 0.27 to 0.23 ns, with a 13.4% improvement. Depending on the prediction period of the
introduced orbits, the Signal-In-Space Range Error (SISRE) of the LEO satellite to Earth can also be improved, from about
9.59 cm without constraints, to 7.38–8.07 cm after constraining the predicted orbits, with an improvement of 16–23%. The
improvements in the SISRE also indicate a better consistency between the real-time clock and orbital estimates. |
| first_indexed | 2025-11-14T11:44:50Z |
| format | Journal Article |
| id | curtin-20.500.11937-95660 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T11:44:50Z |
| publishDate | 2024 |
| publisher | Springer Nature |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-956602024-09-24T08:35:30Z Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained Xie, Wei Su, Hang Wang, Kan Liu, Jiawei El-Mowafy, Ahmed Yang, Xuhai LEO GNSS satellite clock clock prediction Low Earth Orbit (LEO) satellites can augment the traditional GNSS-based positioning, navigation and timing services, which require real-time high-precision LEO satellite clock products. As the complicated systematic efects contained in the LEO satellite clock estimates limit their high-precision mid- to long-term prediction, high-frequency LEO satellite clocks need to be estimated within a Kalman flter, resulting in a short prediction time for real-time applications. Compared to the clock estimation using Batch Least-Squares (BLS) adjustment, flter-based clock estimation experiences a lower precision. Increasing the model strength by introducing external orbital information, thus, de-correlating the orbital and clock param eters, will beneft real-time clock precision. In this contribution, reduced-dynamic LEO satellite orbits are frst estimated using BLS adjustment in near real-time and predicted in the short term. The predicted orbits are then constrained during the Kalman-flter-based clock estimation process. The variance–covariance matrix of the introduced orbital errors is tested for diferent sets of values in the radial, along-track and cross-track directions when constraining orbits of diferent prediction times. One week of GPS data from the Sentinel-3B satellite in 2018 was used for validation of the proposed method. When weakly constraining high-accuracy predicted orbits within a prediction time of 20 min, i.e., with a standard deviation of the constraint set to 2–3 dm in the radial and cross-track directions, and 4–6 dm in the along-track direction, the estimated clock accuracy can be improved from about 0.27 to 0.23 ns, with a 13.4% improvement. Depending on the prediction period of the introduced orbits, the Signal-In-Space Range Error (SISRE) of the LEO satellite to Earth can also be improved, from about 9.59 cm without constraints, to 7.38–8.07 cm after constraining the predicted orbits, with an improvement of 16–23%. The improvements in the SISRE also indicate a better consistency between the real-time clock and orbital estimates. 2024 Journal Article http://hdl.handle.net/20.500.11937/95660 10.1007/s10291-024-01723-6 http://purl.org/au-research/grants/arc/DP240101710 http://creativecommons.org/licenses/by-nc-nd/4.0/ Springer Nature fulltext |
| spellingShingle | LEO GNSS satellite clock clock prediction Xie, Wei Su, Hang Wang, Kan Liu, Jiawei El-Mowafy, Ahmed Yang, Xuhai Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title | Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title_full | Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title_fullStr | Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title_full_unstemmed | Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title_short | Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained |
| title_sort | real-time leo satellite clock estimation with predicted leo satellite orbits constrained |
| topic | LEO GNSS satellite clock clock prediction |
| url | http://purl.org/au-research/grants/arc/DP240101710 http://hdl.handle.net/20.500.11937/95660 |