Realizing rapid re-convergence in multi-GNSS real-time satellite clock offset estimation with dual-thread integer ambiguity resolution

Xie, Wei; Huang, Guanwen; Fu, Wenli; Li, Mengyuan; Du, Shi; Tan, Yue

doi:10.1007/s10291-022-01393-2

Cited by 4 publications

(4 citation statements)

References 32 publications

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“…Figure 16 shows the mean positioning accuracy of each station. It can be observed that the positioning accuracy when using PPP-AR is remarkably better than the ambiguity-float solutions, especially in the E direction [28]. Table 2 presents the mean positioning accuracy for different cases.…”

Section: Ppp Validationmentioning

confidence: 98%

“…The WL ambiguity is insensitive to measurement noise and stable by using multi-epoch smoothing due to its longer wavelength. In this study, for the WL AR, the Rounding method [27] is applied, while for the NL AR, both the least-square ambiguity decorrelation adjustment (LAMBDA) with a better success rate and the Rounding method with less computational time have been applied to estimate the ambiguity-fixed satellite clock offsets [28,29]. To simplify the operation and avoid high-dimensional problems, the Rounding method is used for NL AR in this contribution [30].…”

Section: Upd Estimation and Ar Strategiesmentioning

confidence: 99%

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Real-Time Estimation of BDS-3 Satellite Clock Offset with Ambiguity Resolution Using B1C/B2a Signals

Xie,

Wang,

et al. 2024

Remote Sensing

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The third generation of the BeiDou navigation satellite system (BDS-3) can transmit five-frequency signals. The real-time satellite clock offset of BDS-3 is typically generated utilizing the B1I/B3I combination with the ambiguity-float solutions. By conducting the ambiguity resolution (AR), the reliability of the satellite clock offset can be improved. However, the performance of BDS-3 ambiguity-fixed real-time satellite clock offset with B1C/B2a signals remains unknown and unrevealed. In this contribution, the performance of the BDS-3 ambiguity-fixed satellite clock offset with the new B1C/B2a signals is investigated. One week of observation data from 85 stations was used to perform ambiguity-fixed satellite clock offset estimation. For B1I/B3I and B1C/B2a signals, the wide-lane (WL) uncalibrated phase delay (UPD) on the satellite end is fairly stable for one day, while the narrow-lane (NL) UPD standard deviation (STD) amounts to 0.122 and 0.081 cycles, respectively. The mean ambiguity fixing rate is 80.7% and 78.0% for these two signal combinations, and the time to first fix (TTFF) for the B1C/B2a signals is remarkably shorter than that of the B1I/B3I signals. The STDs of the ambiguity-float and -fixed satellite clock offsets are 0.033 and 0.026 ns, respectively, for the B1I/B3I combination, and it is reduced to 0.024 and 0.023 ns for B1C/B2a signals, respectively. Using the estimated UPD and clock offset products, the positioning performance of the kinematic Precise Point Positioning (PPP)-AR results amounts to 1.56, 1.23, and 4.46 cm in the east, north, and up directions for B1I/B3I signals, respectively. It is improved to 1.36, 1.16, and 4.25 cm using the products estimated with the B1C/B2a signals, with improvements of 12.8%, 5.7%, and 4.7% in three directions, respectively. The experiments showed that the performances of the ambiguity-fixed satellite clock offsets and the PPP-AR results using B1C/B2a signals are better than those of B1I/B3I.

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Section: Ppp Validationmentioning

confidence: 98%

Section: Upd Estimation and Ar Strategiesmentioning

confidence: 99%

Real-Time Estimation of BDS-3 Satellite Clock Offset with Ambiguity Resolution Using B1C/B2a Signals

Xie,

Wang,

et al. 2024

Remote Sensing

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“…In terms of the reference satellite selection method, two schemes are designed in this paper. Scheme 1: GPS, BDS-3 and Galileo kinematic PPP-AR, the reference satellite is the highest-elevation observation [29], and the single-differenced between other satellites and this reference satellite is conducted. Scheme 2: GPS, BDS-3 and Galileo kinematic PPP-AR, a comprehensive evaluation method using entropy weight-grey correlation analysis.…”

Section: Ppp-ar Experiments and Strategiesmentioning

confidence: 99%

PPP-AR reference satellite selection based on the observation quality factors

Li,

Huang,

Wang

et al. 2024

Meas. Sci. Technol.

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In this contribution, we propose a multi-indicators comprehensive evaluation method of the Global Navigation Satellite System (GNSS) based on entropy weight-grey correlation analysis for reference satellite selection of PPP-AR. The comprehensive evaluation includes the observations index selection, the index normalization, the calculation of index entropy weight and the grey correlation analysis. The position dilution of precision (PDOP), carrier-to-noise density ratio (C/N0) and pseudorange multipath indicators are selected to construct a multi-indicator matrix, normalize the above indicators, and then calculate the entropy weight of each evaluation indicator to determine the indicator weights. Meanwhile, after selecting the optimal indicator set, the matrix is constructed to find the grey correlation coefficient and finally the grey correlation degree. According to the above method, the quality ranking of satellite observations for each epoch can be obtained, and the observation value with the highest ranking is used as the reference satellite during the PPP-AR. One-week observations from 243 MGEX stations are selected to conduct GPS-only, Galileo-only and BDS-3-only kinematic PPP-AR, the reference satellite selection method using the highest-elevation and the proposed method is applied, respectively. The results show that, compared with the traditional method, the positioning accuracies, convergence time and ambiguity fixed rates all can be improved using the proposed method. The positioning accuracies of GPS can be improved by about 10.81%, 5.10%, 2.95% and 5.54% in the east(E), north(N), up(U) and three-dimensional(3D) directions, respectively; 7.94%, 5.11%, 5.04% and 6.02% for Galileo; and 14.94%, 5.80%, 3.98% and 8.81% for BDS-3. The average improvements of convergence time in the east, north and up directions are 4.67%, 2% and 4% for GPS, BDS-3 and Galileo, respectively. The ambiguity fixed rates are improved by 7.31%, 6.89% and 1.45% for GPS, BDS-3 and Galileo between the 80%-100% range, respectively.

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“…Regarding the leastsquares adjustment module, only the active parameters in the normal equation are retained to release the computational burden of solving the normal equation (Ge et al 2006). To solve the normal equation, basic matrix operations rely on the BLAS library, while more complex operations such as Cholesky decomposition rely on the LAPACK library (Gong et al 2018, Xie et al 2023. To ensure the quality of the solution, each scheme undergoes two iterations of adjustment before ambiguity fixing.…”

Section: Leo Orbit Accuracymentioning

confidence: 99%

An efficient and robust GNSS/LEO joint orbit determination method based on regional ground control sources

She

Huang

Wang

et al. 2023

Preprint

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The precise orbit determination (POD) for Global Navigation Satellite Systems (GNSS) generally relies on numerous ground-based observations and heavily depends on the geometry of ground stations. Joint orbit determination (JOD) of GNSS satellites and low Earth orbit (LEO) satellites can largely compensate for the limitations of ground station geometry. In the common JOD, the POD of LEO satellite is mainly processed by the reduced-dynamic approach. However, this approach involves complex calculations and is susceptible to disruptions caused by orbit maneuvering. Therefore, a simplified JOD method is designed that employs kinematic approach to determine the LEO satellites orbit. To validate the effectiveness of the proposed method, the orbit and clock offset of GPS satellites and LEO satellites are jointly estimated utilizing the eight regional ground stations. Eight LEO satellites, including GRACE-C, GRACE-D, SWARM-A, SWARM-B, SWARM-C, SENTINEL-3A, SENTINEL-3B, and JASON-3, are chosen for JOD with GPS satellites. Kinematic POD (KPOD) and reduced-dynamic POD (RDPOD) are employed to determine the LEO orbits in the JOD. The comprehensive performance of JOD using different methods for LEO POD is analyzed in terms of GPS orbit accuracy, GPS clock efficiency, LEO orbit accuracy, and computation time. The results show that applying both KPOD and RDPOD methods for LEO satellites led to a substantial improvement in the quality of GPS orbit and clock offset. The adoption of RDPOD yields superior enhancement and results in higher accuracy of the LEO orbits. However, the overall computation is time-consuming and the performance of JOD declines significantly when LEO satellites undergo orbital maneuvers. Alternatively, when employing KPOD, although the accuracy of the LEO orbits in the JOD is comparatively lower, it offers a substantial reduction in the overall network computation time compared to RDPOD. Moreover, the simplified JOD mode based on LEO KPOD is nearly unaffected by orbital maneuvers of LEO satellites, presenting unique advantages in practical data processing.

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Realizing rapid re-convergence in multi-GNSS real-time satellite clock offset estimation with dual-thread integer ambiguity resolution

Cited by 4 publications

References 32 publications

Real-Time Estimation of BDS-3 Satellite Clock Offset with Ambiguity Resolution Using B1C/B2a Signals

Real-Time Estimation of BDS-3 Satellite Clock Offset with Ambiguity Resolution Using B1C/B2a Signals

PPP-AR reference satellite selection based on the observation quality factors

An efficient and robust GNSS/LEO joint orbit determination method based on regional ground control sources

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