Impact of BeiDou satellite-induced code bias variations on precise time and frequency transfer

Zhang, Pengfei; Tu, Rui; Gao, Yuping; Zhang, Rui; Liu, Na

doi:10.1088/1361-6501/aafec1

Cited by 11 publications

(5 citation statements)

References 22 publications

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“…Moreover, Tu et al [17] proposed a model of precise time transfer based on the triple-frequency uncombined observations of the BeiDou navigation satellite system (BDS). Zhang et al [18] developed a satellite-induced code variations model. They indicated that satellite-induced code variations needed to be corrected to improve the acc uracy of the time transfer, especially for long-distance time links.…”

Section: Introductionmentioning

confidence: 99%

A new approach to real-time precise point-positioning timing with International GNSS Service real-time service products

Ge¹,

Qin²,

Su³

et al. 2019

Meas. Sci. Technol.

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Real-time precise timing with the precise point-positioning (PPP) technique is of great interest for scientists. However, real-time precise products are not aligned to a unified time scale. Hence, real-time precise products can only be utilized for time transfer not for timing. Furthermore, if the reference time changes frequently, the receiver clock offset cannot be modelled to further improve the accuracy of timing. In this work, we present a precise satellite timing approach using International GNSS Service (IGS) real-time service products, obtaining the difference between the local time of the user and UTC(k) directly using a global navigation satellite systems (GNSS) receiver. This approach is based on three steps: (1) receiving real-time data streams and receiver observations connected to UTC(k); (2) aligning the reference time of the new precise products to UTC(k) by a PPP approach, with the new precise products then being broadcast via NTRIP (networked transport of RTCM via internet protocol); and (3) obtaining the difference between local time and UTC(k) directly using a GNSS receiver, which can be done by users anywhere on the Earth. Our numerical analyses clarify how our precise timing approach performs using IGS real-time service products. First, the standard deviation (STD) of the difference between the timing results and the receiver clock results released by the IGS final products is approximately 0.2 ns. The STD values of the difference are reduced by approximately 2.76%–25.66% using the between-epoch constraint model. Second, the frequency stability of the timing has a good consistency with the receiver clock offset from the IGS final products with regard to long-term stability, while the short-term stability of the timing with the between-epoch constraint model is better than that of IGS final products. Third, the real-time kinematic positioning accuracy obtained using the new products and CLK93 products is of a similar level when the clock offset is estimated with the white noise model. By using the new products, the positioning accuracy of the between-epoch constraint model is improved by 0.91%, 2.54% and 23.21% over the result without the clock model in three coordinate components.

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Section: Introductionmentioning

confidence: 99%

A new approach to real-time precise point-positioning timing with International GNSS Service real-time service products

Ge¹,

Qin²,

Su³

et al. 2019

Meas. Sci. Technol.

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“…Figure 6 shows the DF time transfer results for GPS, Galileo, and BDS3 overlapping frequency (L1/L5, E1/E5a, B1/B2a) observations at time link BRUX-PTBB (left) and BRUX-KIRU (right), respectively. One can note that the variation of the clock difference series for GPS, Galileo, and BDS3 agreed well both at the BRUX-PTBB (Left) and BRUX-KIRU (Right), although obvious biases exist among the different series, which mainly cause by the different hardware delays for different satellite systems and can be calibrated in the time transfer campaign [35]. Meanwhile, the different estimated coordinate values of station for different satellite systems partly lead to these biases [36,37].…”

Section: Df Time and Frequency Transfermentioning

confidence: 83%

Comparison of Multi-GNSS Time and Frequency Transfer Performance Using Overlap-Frequency Observations

Zhang

Gao

et al. 2021

Remote Sensing

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The modernized GPS, Galileo, and BeiDou global navigation satellite system (BDS3) offers new potential for time transfer using overlap-frequency (L1/E1/B1, L5/E5a/B2a) observations. To assess the performance of time and frequency transfer with overlap-frequency observations for GPS, Galileo, and BDS3, the mathematical models of single- and dual-frequency using the carrier-phase (CP) technique are discussed and presented. For the single-frequency CP model, the three-day average RMS values of the L5/E5a/B2a clock difference series were 0.218 ns for Galileo and 0.263 ns for BDS3, of which the improvements were 36.2% for Galileo and 43.9% for BDS3 when compared with the L1/E1/B1 solution at BRUX–PTBB. For the hydrogen–cesium time link BRUX–KIRU, the RMS values of the L5/E5a/B2a solution were 0.490 ns for Galileo and 0.608 ns for BDS3, improving Galileo by 6.4% and BDS3 by 12.5% when compared with the L1/E1/B1 solution. For the dual-frequency CP model, the average stability values of the L5/E5a/B2a solution at the BRUX–PTBB time link were 3.54∙× 10−12 for GPS, 2.20 × 10−12 for Galileo, and 2.69 × 10−12 for BDS3, of which the improvements were 21.0%, 45.1%, and 52.3%, respectively, when compared with the L1/E1/B1 solution. For the BRUX–KIRU time link, the improvements were 4.2%, 30.5%, and 36.1%, respectively.

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“…With the completion of the BDS and Galileo navigation systems, PPP time transfer technology based on multi-GNSSs will be realized and applied for remote time comparisons in the future. To date, time transfer technology based on BDS-2 has been studied [25,26]. Because the BDS-2 satellites mainly cover the Asia-Pacific region, the number of visible satellites in Europe is not enough for PPP calculations.…”

Section: Bds-3 Time Transfer With the Ppp Methodsmentioning

confidence: 99%

Analysis on the time transfer performance of BDS-3 signals

et al. 2020

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The BeiDou global navigation satellite system (BDS-3) was formally commissioned to provide positioning, velocity, and timing services to global users on 31 July 2020. We analyzed its pseudorange measurement noise, the precision of conventional common view (CV) and all-in-view (AV) time comparison, and the instability of the precise point positioning (PPP) time transfer to assess the time transfer performance of BDS-3. We found that the elevation-dependent biases found in BDS-2 code measurements are mitigated in BDS-3. The time transfer performance of the BDS-3 satellites is over 50% higher than that of the BDS-2 satellites. In terms of the CV time comparison, the standard deviations of the zero-baseline common clock time comparison of the new BDS-3 signal combination of B1C and B2a reach 0.36 ns, which are the same levels for Galileo E1 and E5a and the global positioning system (GPS) L1 and L2. In the long baseline AV comparison links over 7000 km, the standard deviation of the time comparison of the B1C and B2a combination also reaches 0.8 ns, and the improved gain is 55% relative to that of the BDS-2 B1I and B2I. We also tested the PPP time transfer performance with BDS-2 and BDS-3 satellites and found that the time transfer performance of BDS B1I and B3I is comparable to that of GPS L1 and L2.

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Impact of BeiDou satellite-induced code bias variations on precise time and frequency transfer

Cited by 11 publications

References 22 publications

A new approach to real-time precise point-positioning timing with International GNSS Service real-time service products

A new approach to real-time precise point-positioning timing with International GNSS Service real-time service products

Comparison of Multi-GNSS Time and Frequency Transfer Performance Using Overlap-Frequency Observations

Analysis on the time transfer performance of BDS-3 signals

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