Improving the GRACE Kinematic Precise Orbit Determination Through Modified Clock Estimating

Utilizing global positioning system (GPS) to determine the precise kinematic orbits for the twin satellites of the Gravity Recovery and Climate Experiment (GRACE) plays a very important role in the earth’s gravitational and other scientific fields. However, the orbit quality is highly depended on the geometry of observed GPS satellites. In this study, we propose a kinematic orbit determination method for improving the GRACE orbit quality especially when the geometry of observed GPS satellites is weak, where an appropriate random walk clock constraint between adjacent epochs is recommended according to the stability of on-board GPS receiver clocks. GRACE data over one month were adopted in the experimental validation. Results show that the proposed method could improve the root mean square (RMS) by 20–40% in radial component and 5–20% in along and cross components. For those epochs with position dilution of precision (PDOP) larger than 4, the orbits were improved by 50–70% in radial component and 17–50% in along and cross components. Meanwhile, the Allan deviation of clock estimates in the proposed method was much closer to the reported Allan deviation of GRACE on-board oscillator. All the results confirmed the improvement of the proposed method.

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Validation of the EGSIEM-REPRO GNSS Orbits and Satellite Clock Corrections

Remote Sensing ◽

10.3390/rs12142322 ◽

2020 ◽

Vol 12 (14) ◽

pp. 2322 ◽

Cited By ~ 1

Author(s):

Andreja Sušnik ◽

Andrea Grahsl ◽

Daniel Arnold ◽

Arturo Villiger ◽

Rolf Dach ◽

...

Keyword(s):

Orbit Determination ◽

Precise Orbit Determination ◽

Satellite System ◽

Satellite Orbits ◽

Satellite Clock ◽

Gps Satellites ◽

Glonass Satellite ◽

Global Navigation Satellite ◽

Gravity Recovery ◽

First Time

In the framework of the European Gravity Service for Improved Emergency Management (EGSIEM) project, consistent sets of state-of-the-art reprocessed Global Navigation Satellite System (GNSS) orbits and satellite clock corrections have been generated. The reprocessing campaign includes data starting in 1994 and follows the Center for Orbit Determination in Europe (CODE) processing strategy, in particular exploiting the extended version of the empirical CODE Orbit Model (ECOM). Satellite orbits are provided for Global Positioning System (GPS) satellites since 1994 and for Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) since 2002. In addition, a consistent set of GPS satellite clock corrections with 30 s sampling has been generated from 2000 and with 5 s sampling from 2003 onwards. For the first time in a reprocessing scheme, GLONASS satellite clock corrections with 30 s sampling from 2008 and 5 s from 2010 onwards were also generated. The benefit with respect to earlier reprocessing series is demonstrated in terms of polar motion coordinates. GNSS satellite clock corrections are validated in terms of completeness, Allan deviation, and precise point positioning (PPP) using terrestrial stations. In addition, the products herein were validated with Gravity Recovery and Climate Experiment (GRACE) precise orbit determination (POD) and Satellite Laser Ranging (SLR). The dataset is publicly available.

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Enhancing the kinematic precise orbit determination of low earth orbiters using GPS receiver clock modelling

Advances in Space Research ◽

10.1016/j.asr.2014.07.016 ◽

2014 ◽

Vol 54 (9) ◽

pp. 1901-1912 ◽

Cited By ~ 8

Author(s):

Yang Yang ◽

Xiaokui Yue ◽

Jianping Yuan ◽

Chris Rizos

Keyword(s):

Orbit Determination ◽

Precise Orbit Determination ◽

Gps Receiver ◽

Precise Orbit ◽

Receiver Clock

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Characteristics of BeiDou-3 Experimental Satellite Clocks

Remote Sensing ◽

10.3390/rs10111847 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1847 ◽

Cited By ~ 7

Author(s):

Yifei Lv ◽

Tao Geng ◽

Qile Zhao ◽

Jingnan Liu

Keyword(s):

Global Positioning System ◽

Precise Orbit Determination ◽

Frequency Standard ◽

Step Method ◽

Stability Performance ◽

Global Positioning ◽

Clock Prediction ◽

Block Iif ◽

The Stability ◽

Gps Block Iif

The characteristics of the improved Atomic Frequency Standard (AFS) operated on the latest BeiDou-3 experimental satellites are analyzed from day-of-year (DOY) 254 to 281, of the year 2017, considering the following three aspects: stability, periodicity, and prediction precision. The two-step method of Precise Orbit Determination (POD) is used to obtain the precise clock offsets. We presented the stability of such new clocks and studied the influence of the uneven distribution of the ground stations on the stability performance of the clock. The results show that the orbit influence on the Medium Earth Orbit (MEO) clock offsets is the largest of three satellite types, especially from 3 × 10 3 s to 8.64 × 10 4 s. Considering this orbit influence, the analysis shows that the Passive Hydrogen Maser (PHM) clock carried on C32 is approximately 2.6 × 10 − 14 at an interval of 10 4 , and has the best stability for any averaging intervals among the BeiDou satellite clocks, which currently achieves a level comparable to that of the PHM clock of Galileo, and the rubidium (Rb) clocks of Global Positioning System (GPS) Block IIF. The stability of the improved Rb AFS on BeiDou-3 is also superior to that of BeiDou-2 from 3 × 10 2 s to 3 × 10 3 s, and comparable to that of Rb AFS on the Galileo. Moreover, the periodicity of the PHM clock and the improved Rb clock are presented. For the PHM clock, the amplitudes are obviously reduced, while the new Rb clocks did not show a visible improvement, which will need further analysis in the future. As expected, the precision of the short-term clock prediction is improved because of the better characteristics of AFS. The Root Mean Square (RMS) of 1-h clock prediction is less than 0.16 ns.

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Precise Orbit Determination for GNSS Maneuvering Satellite with the Constraint of a Predicted Clock

Remote Sensing ◽

10.3390/rs11161949 ◽

2019 ◽

Vol 11 (16) ◽

pp. 1949 ◽

Cited By ~ 3

Author(s):

Xiaolei Dai ◽

Yidong Lou ◽

Zhiqiang Dai ◽

Caibo Hu ◽

Yaquan Peng ◽

...

Keyword(s):

Orbit Determination ◽

Precise Orbit Determination ◽

Satellite System ◽

Navigation Satellite ◽

Precise Orbit ◽

Gps Satellites ◽

Global Navigation Satellite ◽

Cross Track ◽

Along Track ◽

Backward Integration

Precise orbit products are essential and a prerequisite for global navigation satellite system (GNSS) applications, which, however, are unavailable or unusable when satellites are undertaking maneuvers. We propose a clock-constrained reverse precise point positioning (RPPP) method to generate the rather precise orbits for GNSS maneuvering satellites. In this method, the precise clock estimates generated by the dynamic precise orbit determination (POD) processing before maneuvering are modeled and predicted to the maneuvering periods and they constrain the RPPP POD during maneuvering. The prediction model is developed according to different clock types, of which the 2-h prediction error is 0.31 ns and 1.07 ns for global positioning system (GPS) Rubidium (Rb) and Cesium (Cs) clocks, and 0.45 ns and 0.60 ns for the Beidou navigation satellite system (BDS) geostationary orbit (GEO) and inclined geosynchronous orbit (IGSO)/Median Earth orbit (MEO) satellite clocks, respectively. The performance of this proposed method is first evaluated using the normal observations without maneuvers. Experiment results show that, without clock-constraint, the average root mean square (RMS) of RPPP orbit solutions in the radial, cross-track and along-track directions is 69.3 cm, 5.4 cm and 5.7 cm for GPS satellites and 153.9 cm, 12.8 cm and 10.0 cm for BDS satellites. When the constraint of predicted satellite clocks is introduced, the average RMS is dramatically reduced in the radial direction by a factor of 7–11, with the value of 9.7 cm and 13.4 cm for GPS and BDS satellites. At last, the proposed method is further tested on the actual GPS and BDS maneuver events. The clock-constrained RPPP POD solution is compared to the forward and backward integration orbits of the dynamic POD solution. The resulting orbit differences are less than 20 cm in all three directions for GPS satellite, and less than 30 cm in the radial and cross-track directions and up to 100 cm in the along-track direction for BDS satellites. From the orbit differences, the maneuver start and end time is detected, which reveals that the maneuver duration of GPS satellites is less than 2 min, and the maneuver events last from 22.5 min to 107 min for different BDS satellites.

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GRACE-FO precise orbit determination and gravity recovery

Journal of Geodesy ◽

10.1007/s00190-020-01414-3 ◽

2020 ◽

Vol 94 (9) ◽

Author(s):

Z. Kang ◽

S. Bettadpur ◽

P. Nagel ◽

H. Save ◽

S. Poole ◽

...

Keyword(s):

Orbit Determination ◽

Precise Orbit Determination ◽

Precise Orbit ◽

Gravity Recovery

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Real-time precise orbit determination of LEO satellites using a single-frequency GPS receiver: Preliminary results of Chinese SJ-9A satellite

Advances in Space Research ◽

10.1016/j.asr.2017.06.052 ◽

2017 ◽

Vol 60 (7) ◽

pp. 1478-1487 ◽

Cited By ~ 3

Author(s):

Xiucong Sun ◽

Chao Han ◽

Pei Chen

Keyword(s):

Real Time ◽

Orbit Determination ◽

Precise Orbit Determination ◽

Single Frequency ◽

Gps Receiver ◽

Preliminary Results ◽

Precise Orbit ◽

Leo Satellites

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Performance Comparison of KOMPSAT-5 Precision Orbit Determination with GRACE

International Journal of Aerospace Engineering ◽

10.1155/2020/7358286 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Kyoung-Min Roh ◽

Yoola Hwang

Keyword(s):

Orbit Determination ◽

Hardware Design ◽

Performance Comparison ◽

Gps Receiver ◽

Ring Antenna ◽

Orbital Position ◽

Grace Satellites ◽

Precision Orbit Determination ◽

Gravity Recovery ◽

Reduced Dynamic

The Korean Multipurpose Satellite-5 (KOMPSAT-5) launched on 22 August 2013 was equipped with a global positioning system (GPS) receiver for precision orbit determination (POD). Even though the GPS receiver of KOMPSAT-5 shares the same heritage as the BlackJack receiver onboard in Gravity Recovery and Climate Experiment (GRACE) satellites, KOMPSAT-5 has a lower orbital position accuracy (~10 cm) compared with GRACE (~2 cm). The reduced dynamic and kinematic methods are applied for POD of KOMPSAT-5 and GRACE to investigate the GPS observation quality due to the satellite operation concept and hardware design. The results are analyzed in terms of the number of observations and their spatial distribution, GPS signal quality, and orbital position accuracies. The results show that the frequent attitude maneuvers of KOMPSAT-5 affect the quality of the GPS signals and solutions obtained from the kinematic method compared with that determined from the reduced-dynamic method. The onboard patch GPS antenna installed in KOMPSAT-5 and its geometrical position resulted in more erratic measurement residuals by 140% compared with the choke ring antenna of GRACE. The POD accuracy is dependent on the hardware design and regular attitude tilting for the synthetic aperture radar (SAR) imaging even though the same GPS receiver performances.

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