Analysis of satellite-induced factors affecting the accuracy of the BDS satellite differential code bias

Shu, Bao; Liu, Hui; Xu, Lianfei; Gong, Xiaopeng; Qian, Chuang; Zhang, Ming; Zhang, Rufei

doi:10.1007/s10291-016-0577-2

Cited by 12 publications

(9 citation statements)

References 18 publications

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“…Figure 2 shows that peak amplitudes vary from one millimeter to tens of millimeters for different BDS-2 satellites. Peak amplitudes for all IGSO satellites appear at 24 h, while those for all MEO satellites are close to 12 h. Different with IGSO and MEO satellites that have only one peak amplitude, two peak amplitudes for three GEO satellites can be found at 24 h and 12 h. The results are consistent with the orbital period of GEO, IGSO and MEO satellites (Shu et al 2017), which indicates that a second-order periodic function related to the sun-spacecraft-earth angle is suitable for modeling BDS-2 independent satellite PIFCB variations. In this study, the variations could be regarded as small enough to be ignored for the satellites whose peak amplitudes are much smaller than the noise of the GFIF combination of the carrier-phase observations.…”

Section: Model Implementation Using Bds-2 and Bds-3 Multi-frequency Datasupporting

confidence: 78%

GNSS satellite inter-frequency clock bias estimation and correction based on IGS clock datum: a unified model and result validation using BDS-2 and BDS-3 multi-frequency data

Fan

Wang

Guo

et al. 2021

J Geod

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To deal with inconsistency between Global Navigation Satellite System (GNSS) multi-frequency data and International GNSS Service (IGS) clock product, we propose a unified model for GNSS satellite inter-frequency clock bias (IFCB) estimation and correction based on the IGS clock datum. The proposed model is rigorously derived by three sequential steps. First, by means of accurate modeling of the time-variant part of satellite phase-based IFCB (PIFCB) and introducing a zero-mean condition for satellite code-based IFCB (CIFCB), a set of independent satellite IFCBs are estimated in a full-rank multi-frequency uncombined model where IGS orbit and clock products are taken as input. The independent satellite IFCB refers to hardware delay difference between a specified frequency and two reference frequencies that are used for generating the IGS product. In the second step, a linear equation between satellite IFCBs from any three frequencies and the independent satellite IFCB estimates is derived. Based on this equation, the third step aims to establish a general satellite IFCB correction model which is used to align data on any two frequencies to the IGS clocks. The proposed model is implemented and validated using one month of multi-frequency data from BeiDou regional system (BDS-2) and BeiDou global system (BDS-3), i.e., B1I, B2I, B3I, B1C, B2a and B2b. By choosing B1I and B3I as reference frequencies, periodic analysis results suggest that a second-order periodic function is suitable for modeling BDS-2 independent satellite PIFCB variations. Yet there is no need to introduce periodic function into BDS-3 independent satellite PIFCB variations at all frequencies. For observation types of 1X (B1C), 5X (B2a) and 7Z (B2b), the standard deviation (STD) of three independent CIFCB estimates at each BDS-3 new frequency (i.e., B1C, B2a and B2b) and one CIFCB from the three new frequencies for all BDS-3 satellites are 3.14, 0.09, 0.12 and 0.09 ns, while those for the observation types of 1P (B1C), 5P (B2a) and 7D (B2b) are 2.52, 0.08, 0.08 and 0.04 ns, respectively. A major reason for the large noise of the independent satellite CIFCB at frequency B1C is that the frequency value of B1C is very close to that of B1I. Using the satellite IFCB estimates as corrections, the average RMS of kinematic precise point positioning (PPP) errors using ionosphere-free combination of BDS-3 multi-frequency data is 2.7 and 5.0 cm on horizontal and up directions, respectively, showing a same level with that of B1I/B3I-based PPP. In comparison, the accuracy of PPP is decreased by several millimeters during convergence when the differential code bias (DCB) product is used for correction. Keywords BDS-2 • BDS-3 • Inter-frequency clock bias • Multi-frequency • Uncombined model • Differential code bias B Cheng Wang

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Section: Model Implementation Using Bds-2 and Bds-3 Multi-frequency Datasupporting

confidence: 78%

GNSS satellite inter-frequency clock bias estimation and correction based on IGS clock datum: a unified model and result validation using BDS-2 and BDS-3 multi-frequency data

Fan

Wang

Guo

et al. 2021

J Geod

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“…The precise correction of SICB resulted in a significant improvement of larger than 75% for wide-lane uncalibrated phase delay (UPD) estimation and a minor improvement of less than 25% for narrow-lane UPD estimation with respect to the PPP ambiguity resolution [14]. The long-term stability of differential code bias (DCB) for BDS-2 MEO satellites was improved by 12-28% after the SICB was corrected [15]. In this contribution, the single-frequency PPP is also used to verify our proposed SICB correction model.…”

Section: Introductionmentioning

confidence: 99%

An Improved BDS Satellite-Induced Code Bias Correction Model Considering the Consistency of Multipath Combinations

Pan

Guo

2018

Remote Sensing

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The satellite-induced systematic biases were identified to exist in the code observations from BeiDou navigation satellite system (BDS) satellites using multipath (MP) combinations. The current correction model for satellite-induced code bias (SICB) does not take into account the consistency of MP combinations, which limits the accuracy of the developed model. Both the cycle slips and different tracking of a satellite at different stations can affect the absolute values of MP combinations, although the variations remain unchanged. An improved SICB piecewise linear correction model as a function of elevations is proposed. We estimate the model parameters for each frequency and for each satellite. The single-difference of MP combinations in the domain of elevation angles is carried out to remove the unknown ambiguities and stable hardware delays so that the SICB modeling is free of the effects of MP combination inconsistency. In addition, a denser elevation node separation of 1°, rather than the 10° usually employed by the traditional model, is used to describe the more precise SICB variations. The SICB corrections show significant differences among orbit types and frequency bands. The SICB variations have much less effect on Inclined Geosynchronous Orbit (IGSO) satellites than on Medium Earth Orbit (MEO) satellites for the regional BDS (BDS-2). The B1 signal has the largest SICB corrections, which can be up to 0.9 m close to zenith for BDS-2 MEO satellites, and the B2 signal follows. After adding the SICB corrections to the code observations, the elevation-dependent code biases vanish, and we can obtain improved code observations. After applying the improved SICB correction model, the root mean square (RMS) values of MP combination time series are reduced by 7%, 6% and 2%, and 18%, 14% and 5% on the B1, B2 and B3 frequencies for the BDS-2 IGSO and MEO satellites, respectively. For comparison, we also establish the traditional SICB correction model. With the traditional SICB correction model, the corresponding RMS MP combinations are smaller than those of uncorrected MP series, but slightly larger than those of corrected MP series using the improved SICB correction model. To validate the effectiveness and correctness of our proposed model, single-frequency precise point positioning (PPP) processing with BDS-2 MEO and IGSO satellites is conducted. An accuracy improvement of 24%, 19% and 89%, and 7%, 7% and 6% for the single-frequency PPP applying the improved SICB corrections over the case without SICB corrections and the case using the traditional SICB corrections in east, north and vertical directions is achieved, respectively. Although only centimeter-level SICB variations could be observed for the two legacy signals B1 and B3 and the three new navigation signals B1C, B2a and B2b transmitted by the satellites of global BDS demonstration system (BDS-3S), we still establish an effective SICB correction model on the B1 and B3 frequencies for BDS-3S IGSO satellites, and the RMS MP combinations are reduced by 1–4% after applying the improved SICB corrections.

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“…The reason may be that the orbital period of BDS IGSO satellite is one day and that of BDS MEO satellite is seven days. Thus, some unmodeled error will decrease the accuracy of estimated MEO pseudorange bias [12,26].…”

Section: Bds Pseudorange Bias Calibrationmentioning

confidence: 99%

Calibration of BeiDou Triple-Frequency Receiver-Related Pseudorange Biases and Their Application in BDS Precise Positioning and Ambiguity Resolution

Zheng

Gong

Lou

et al. 2019

Sensors

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Global Navigation Satellite System pseudorange biases are of great importance for precise positioning, timing and ionospheric modeling. The existence of BeiDou Navigation Satellite System (BDS) receiver-related pseudorange biases will lead to the loss of precision in the BDS satellite clock, differential code bias estimation, and other precise applications, especially when inhomogeneous receivers are used. In order to improve the performance of BDS precise applications, two ionosphere-free and geometry-free combinations and ionosphere-free pseudorange residuals are proposed to calibrate the raw receiver-related pseudorange biases of BDS on each frequency. Then, the BDS triple-frequency receiver-related pseudorange biases of seven different manufacturers and twelve receiver models are calibrated. Finally, the effects of receiver-related pseudorange bias are analyzed by BDS single-frequency single point positioning (SPP), single- and dual-frequency precise point positioning (PPP), wide-lane uncalibrated phase delay (UPD) estimation, and ambiguity resolution, respectively. The results show that the BDS SPP performance can be significantly improved by correcting the receiver-related pseudorange biases and the accuracy improvement is about 20% on average. Moreover, the accuracy of single- and dual-frequency PPP is improved mainly due to a faster convergence when the receiver-related pseudorange biases are corrected. On the other hand, the consistency of wide-lane UPD among different stations is improved significantly and the standard deviation of wide-lane UPD residuals is decreased from 0.195 to 0.061 cycles. The average success rate of wide-lane ambiguity resolution is improved about 42.10%.

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Analysis of satellite-induced factors affecting the accuracy of the BDS satellite differential code bias

Cited by 12 publications

References 18 publications

GNSS satellite inter-frequency clock bias estimation and correction based on IGS clock datum: a unified model and result validation using BDS-2 and BDS-3 multi-frequency data

GNSS satellite inter-frequency clock bias estimation and correction based on IGS clock datum: a unified model and result validation using BDS-2 and BDS-3 multi-frequency data

An Improved BDS Satellite-Induced Code Bias Correction Model Considering the Consistency of Multipath Combinations

Calibration of BeiDou Triple-Frequency Receiver-Related Pseudorange Biases and Their Application in BDS Precise Positioning and Ambiguity Resolution

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