Reducing convergence time of precise point positioning with ionospheric constraints and receiver differential code bias modeling

Xiang, Yan; Gao, Yang; Li, Yihe

doi:10.1007/s00190-019-01334-x

Cited by 28 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference in the proportions of SD ionospheric residuals between the 165-km network and the 50-km network was associated with the ionospheric modeling errors. The errors mainly depend on the distance between stations (Xiang et al 2020). Meanwhile, it is also noted that the ionospheric parameters not only have uncertain random variations but also contain the receiver's DCBs.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of the performance of GPS/Galileo PPP-RTK convergence using ionospheric corrections from networks with different scales

Yan

Zhang

2022

Earth Planets Space

View full text Add to dashboard Cite

The rapid convergence of precise point positioning real-time kinematics (PPP-RTK) with centimeter-level accuracy is of utmost importance for many applications. One way of accelerating this convergence is to explore the use of ionospheric models and multiple global navigation satellite system (GNSS) observations, e.g., Global Positioning System (GPS) and Galileo Satellite Navigation System (Galileo) observations. Because the temporal and spatial variations of the ionosphere are significant, convergence analysis of PPP-RTK should be investigated in networks with different scales, especially networks with large differences in their scales. This study describes the convergence performance of PPP-RTK using GPS/Galileo observations derived from networks with different scales under medium ionospheric conditions. Slant ionospheric corrections were first estimated from the reference network and then imported as virtual observations to enhance the convergence performance of PPP-RTK at the user interface. The results show that for the 165-km reference site spacing, the portions of single-differenced (SD) ionospheric residuals within 0.3 total electron content units (TECU) were 85.2% and 81.7% for the GPS and Galileo observations, respectively. Considering the 90th percentile of horizontal position errors, the PPP-RTK convergence time within the network with 165-km spacing was shortened from 2.5 min for GPS-only observations to 2.0 min for integrated GPS + Galileo observations. For the network of about 50 km, the proportions of the SD ionospheric residuals of the GPS and Galileo constellation within 0.3 TECU were 95.9% and 82.8%, respectively. The PPP-RTK convergence time of the 90th percentile horizontal positioning errors based on GPS-only observations was 2.0 min but 1.5 min based on integrated GPS + Galileo observations. Using GPS and Galileo observations, the convergence time could be reduced by 25% for the network with 50-km spacing. Our results suggest that the convergence time of PPP-RTK depends on the scale of the reference network and becomes shorter as the scale of the network decreases. Compared with the GPS-only PPP-RTK, the GPS/Galileo PPP-RTK could shorten the convergence time further. Graphical Abstract

show abstract

Section: Discussionmentioning

confidence: 99%

“…If we consider the ionospheric free (IF) satellite clocks, the UCPPP model can be reparametrized as (Laurichesse and Privat 2015;Xiang et al 2020…”

Section: Ucppp Observation Equationsmentioning

confidence: 99%

Assessment of the performance of GPS/Galileo PPP-RTK convergence using ionospheric corrections from networks with different scales

Yan

Zhang

2022

Earth Planets Space

View full text Add to dashboard Cite

show abstract

“…Over the past few decades, many interpolated algorithms have been developed [46][47][48]. Because the interpolated errors mainly represent distance-dependent biases, the distance-based linear interpolation method (DIM) can be used to interpolate atmospheric delays [49]. Using the DIM approach, atmospheric corrections of satellite s visible to the user are interpolated from n reference stations and weighted by the inverse distance between the reference network and the user stations.…”

Section: Estimation Representation and Constraint Of Atmospheric Corr...mentioning

confidence: 99%

“…One is the uncertainty due to multiple path errors and observation noise. The other is the interpolated error, which mainly depends on the distance between the reference site and user location [49]. Normally, the variance of atmospheric corrections increases as the distance between the reference network and user increases.…”

Section: Estimation Representation and Constraint Of Atmospheric Corr...mentioning

confidence: 99%

The Performance of Three-Frequency GPS PPP-RTK with Partial Ambiguity Resolution

Yan

Zhang

2022

Atmosphere

View full text Add to dashboard Cite

The correct ambiguity resolution of real-time kinematic precise point positioning (PPP-RTK) plays an essential role in achieving fast, reliable, and high-precision positioning. However, the ambiguity of incorrect fixing will cause poor PPP-RTK positioning performance. Hence, it is essential to optimize the selected strategy of the ambiguity subset to obtain a more reliable ambiguity resolution performance for PPP-RTK. For this reason, a partial ambiguity resolution (PAR) method combining quality control and Schmidt orthogonalization (Gram–Schmidt) is proposed in this study. To investigate the performance of global positioning system (GPS) dual- and three-frequency PPP-RTK comprehensively, the PAR method based on the Gram–Schmidt method was analyzed and compared with the highest elevation angle method, which considered the satellite with the highest elevation angle as the reference satellite. The performance of ambiguity fixing, atmospheric corrections, and positioning were evaluated using five stations in Belgium and its surrounding area. The results showed average epoch fixing rates of 81.01%, 95.92%, 82.05%, and 97.93% in the dual-frequency highest elevation angle (F2-MAX), dual-frequency Gram–Schmidt (F2-ALT), three-frequency highest elevation angle (F3-MAX), and three–frequency Gram–Schmidt (F3-ALT), respectively. In terms of the time to first fix (TTFF), 89.02%, 94.25%, 90.24%, and 95.69% of the single-differenced (SD) narrow lane (NL) ambiguity fell within 3 min in F2-MAX, F2-ALT, F3-MAX, and F3-ALT, respectively. As far as the ionospheric corrections are concerned, the proportion of SD ionospheric residuals within ±0.25 total electron content units (TECU) were 95.08%, 95.93%, 95.68%, and 96.98% for the F2-MAX, F2-ALT, F3-MAX, and F3-ALT, respectively. The centimeter-level accuracy of both the horizontal and vertical positioning errors can be achieved almost instantaneously in F3-ALT. This is attributed to the accurate and reliable SD NL ambiguity fixing based on the Gram–Schmidt approach.

show abstract

“…Since then, improvements in the algorithms have led to reduction of the convergence time, as well as betterment of the accuracies. For instance, the use of external atmospheric corrections has been included in the PPP model with a non-negligible impact on the initial errors and convergence time of PPP solutions, as shown in [ 3 , 4 ]. Another area of algorithmic improvement is ambiguity resolution.…”

Section: Introductionmentioning

confidence: 99%

Exploring Signals on L5/E5a/B2a for Dual-Frequency GNSS Precise Point Positioning

Naciri

Hauschild

Bisnath

2021

Sensors

View full text Add to dashboard Cite

Due to its nature, Precise Point Positioning (PPP) depends on the GNSS measurements and quality of satellite correction products used to relatively quickly provide precise and accurate positions. With the rapid evolution of Global Navigation Satellite Systems (GNSSs), new frequencies and signals are being broadcast, which have a positive impact on PPP performance. This paper presents, for the first time, a comprehensive analysis of PPP performance from these new GPS, Galileo and BeiDou-2/3 signals, which are not yet commonly used for PPP, with correct mitigation of errors such as the estimation of GPS Block-IIF L5 variations. Satellite orbits and clocks, as well as GPS Block-IIF L5 corrections, are estimated in real-time using DLR’s RETICLE engine, while the user processing is performed with York University’s PPP engine. First, as a reference, PPP performance is assessed on widely used signals: GPS L1/L2, Galileo E1/E5a, and BeiDou-2/3 B1-2/B3. Horizontal and vertical rms of 2.3 and 2.6 cm, respectively, are achieved in static processing and 5.4 and 7.5 cm in kinematic processing after 1 h of processing using real-time satellite correction products. The compatibility of BeiDou-2 and BeiDou-3 on the shared B1-2/B3 frequencies is analyzed and discrepancies in the receiver clock are found. Next, since all three constellations share two common frequencies, the paper focuses on analyzing PPP performance of GPS, Galileo and BeiDou-3 on [L1, E1, B1] at 1575.42 MHz and [L5, E5a, B2a] at 1176.45 MHz. Horizontal and vertical rms of 6.9 and 7.1 cm are achieved in kinematic processing. The effect of the known GPS Block-IIF L5 biases is studied as well, as it is shown to affect the receiver position and clock, as well as the ionospheric estimates and ambiguities. Average improvements of 15% and 20% in the horizontal and vertical rms, respectively, are observed when these biases are mitigated.

show abstract

Reducing convergence time of precise point positioning with ionospheric constraints and receiver differential code bias modeling

Cited by 28 publications

References 33 publications

Assessment of the performance of GPS/Galileo PPP-RTK convergence using ionospheric corrections from networks with different scales

Assessment of the performance of GPS/Galileo PPP-RTK convergence using ionospheric corrections from networks with different scales

The Performance of Three-Frequency GPS PPP-RTK with Partial Ambiguity Resolution

Exploring Signals on L5/E5a/B2a for Dual-Frequency GNSS Precise Point Positioning

Contact Info

Product

Resources

About