Improving BDS integer ambiguity resolution using satellite-induced code bias correction for precise orbit determination

The real-time integer-ambiguity resolution of the carrier-phase observation is one of the most effective approaches to enhance the accuracy of real-time precise point positioning (PPP), kinematic precise orbit determination (KPOD), and reduced-dynamic precise orbit determination (RPOD) for low earth orbit (LEO) satellites. In this study, the integer phase clock (IPC) and wide-lane satellite bias (WSB) products from CNES (Centre National d’Etudes Spatiales) are used to fix ambiguity in real time. Meanwhile, the three models of real-time PPP, KPOD, and RPOD are applied to validate the contribution of ambiguity resolution. Experimental results show that (1) the average positioning accuracy of IGS stations for ambiguity-fixed solutions is improved from about 7.14 to 5.91 cm, with an improvement of around 17% compared to the real-time float PPP solutions, with enhancement in the east-west direction particularly significant, with an improvement of about 29%; (2) the average accuracy of the estimated LEO orbit with ambiguity-fixed solutions in the real-time KPOD and RPOD mode is improved by about 16% and 10%, respectively, with respect to the corresponding mode with the ambiguity-float solutions; (3) the performance of real-time LEO RPOD is better than that of the corresponding KPOD, regardless of fixed- or float-ambiguity solutions. Moreover, the average ambiguity-fixed ratio can reach more than 90% in real-time PPP, KPOD, and RPOD.

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Assessment of single-difference and track-to-track ambiguity resolution in LEO precise orbit determination

GPS Solutions ◽

10.1007/s10291-021-01103-4 ◽

2021 ◽

Vol 25 (2) ◽

Author(s):

Xingyu Zhou ◽

Hua Chen ◽

Wenlan Fan ◽

Xiaohui Zhou ◽

Qusen Chen ◽

...

Keyword(s):

Ambiguity Resolution ◽

Orbit Determination ◽

Precise Orbit Determination ◽

Precise Orbit ◽

Single Difference

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Real-Time Kinematic Precise Orbit Determination for LEO Satellites Using Zero-Differenced Ambiguity Resolution

Remote Sensing ◽

10.3390/rs11232815 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2815 ◽

Cited By ~ 1

Author(s):

Xingxing Li ◽

Jiaqi Wu ◽

Keke Zhang ◽

Xin Li ◽

Yun Xiong ◽

...

Keyword(s):

Real Time ◽

Ambiguity Resolution ◽

Orbit Determination ◽

Precise Orbit Determination ◽

The Real ◽

Precise Orbit ◽

Ambiguity Fixing ◽

Real Time Kinematic ◽

Leo Satellites ◽

Fixed Solution

The rapid growing number of earth observation missions and commercial low-earth-orbit (LEO) constellation plans have provided a strong motivation to get accurate LEO satellite position and velocity information in real time. This paper is devoted to improve the real-time kinematic LEO orbits through fixing the zero-differenced (ZD) ambiguities of onboard Global Navigation Satellite System (GNSS) phase observations. In the proposed method, the real-time uncalibrated phase delays (UPDs) are estimated epoch-by-epoch via a global-distributed network to support the ZD ambiguity resolution (AR) for LEO satellites. By separating the UPDs, the ambiguities of onboard ZD GPS phase measurements recover their integer nature. Then, wide-lane (WL) and narrow-lane (NL) AR are performed epoch-by-epoch and the real-time ambiguity–fixed orbits are thus obtained. To validate the proposed method, a real-time kinematic precise orbit determination (POD), for both Sentinel-3A and Swarm-A satellites, was carried out with ambiguity–fixed and ambiguity–float solutions, respectively. The ambiguity fixing results indicate that, for both Sentinel-3A and Swarm-A, over 90% ZD ambiguities could be properly fixed with the time to first fix (TTFF) around 25–30 min. For the assessment of LEO orbits, the differences with post-processed reduced dynamic orbits and satellite laser ranging (SLR) residuals are investigated. Compared with the ambiguity–float solution, the 3D orbit difference root mean square (RMS) values reduce from 7.15 to 5.23 cm for Sentinel-3A, and from 5.29 to 4.01 cm for Swarm-A with the help of ZD AR. The SLR residuals also show notable improvements for an ambiguity–fixed solution; the standard deviation values of Sentinel-3A and Swarm-A are 4.01 and 2.78 cm, with improvements of over 20% compared with the ambiguity–float solution. In addition, the phase residuals of ambiguity–fixed solution are 0.5–1.0 mm larger than those of the ambiguity–float solution; the possible reason is that the ambiguity fixing separate integer ambiguities from unmodeled errors used to be absorbed in float ambiguities.

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Combined precise orbit determination of GPS and GLONASS with ambiguity resolution

Journal of Geodesy ◽

10.1007/s00190-019-01321-2 ◽

2019 ◽

Vol 93 (12) ◽

pp. 2585-2603

Author(s):

Xiangdong An ◽

Xiaolin Meng ◽

Hua Chen ◽

Weiping Jiang ◽

Ruijie Xi ◽

...

Keyword(s):

Ambiguity Resolution ◽

Orbit Determination ◽

Precise Orbit Determination ◽

Precise Orbit

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BDS-2 and BDS-3 combined precise orbit determination with hybrid ambiguity resolution

Measurement ◽

10.1016/j.measurement.2021.110593 ◽

2021 ◽

pp. 110593

Author(s):

Yaquan Peng ◽

Xiaolei Dai ◽

Yidong Lou ◽

Xiaopeng Gong ◽

Fu Zheng

Keyword(s):

Ambiguity Resolution ◽

Orbit Determination ◽

Precise Orbit Determination ◽

Precise Orbit

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Reduced-Dynamic Precise Orbit Determination of Haiyang-2B Altimetry Satellite Using a Refined Empirical Acceleration Model

Remote Sensing ◽

10.3390/rs13183702 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3702

Author(s):

Youcun Wang ◽

Min Li ◽

Kecai Jiang ◽

Wenwen Li ◽

Geer Qin ◽

...

Keyword(s):

Orbit Determination ◽

Carrier Phase ◽

Precise Orbit Determination ◽

Geometric Constraints ◽

Integer Ambiguity ◽

Time Variability ◽

Precise Orbit ◽

Acceleration Model ◽

Gps Antenna ◽

Reduced Dynamic

The Haiyang 2B (HY-2B) satellite requires precise orbit determination (POD) products for geodetic remote sensing techniques. An improved set of reduced-dynamic (RD) orbit solutions was generated from the onboard Global Positioning System (GPS) measurements over a 14-month period using refined strategies and processing techniques. The key POD strategies include a refined empirical acceleration model, in-flight calibration of the GPS antenna, and the resolution of single-receiver carrier-phase ambiguities. In this study, the potential periodicity of empirical acceleration in the HY-2B POD was identified by spectral analysis. In the along-track direction, a noticeable signal with four cycles per revolution (CPR) was significant. A mixed spectrum was observed for the cross-track direction. To better understand the real in-flight environment, a refined empirical acceleration model was used to cope with the time variability of empirical accelerations in HY-2B POD. Three POD strategies were used for the reprocessing for superior orbit quality. Validation using over one year of satellite laser ranging (SLR) measurements demonstrated a 5.2% improvement in the orbit solution of the refined model. Reliable correction for the GPS antenna phase center was obtained from an over-420-day dataset, and a trend in radial offset change was observed. After application of the in-flight calibration of the GPS antenna, a 26% reduction in the RMS SLR residuals was achieved for the RD orbit solution, and the carrier phase residuals were clearly reduced. The integer ambiguity resolution of HY-2B led to strong geometric constraints for the estimated parameters, and a 15% improvement in the SLR residuals could be inferred compared with the float solution.

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