Influence of the inhomogeneous troposphere on GNSS positioning and integer ambiguity resolution

Ma, Hongyang; Psychas, Dimitrios; Xing, Xuhuang; Zhao, Qile; Verhagen, Sandra; Liu, Xianglin

doi:10.1016/j.asr.2020.12.043

Cited by 14 publications

(7 citation statements)

References 35 publications

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“…On the other hand, some extreme weather conditions cause the drastic changes in the troposphere. It will affect the tropospheric model's accuracy and, consequently, the positioning performance (Ma et al, 2021). Therefore, another challenge in troposphere modeling is how to identify the abnormal changes in the troposphere error and reflect the small-scale changes in the model.…”

Section: Troposphere Modeling Under Complex Terrain and Weather Condi...mentioning

confidence: 99%

Review of PPP–RTK: achievements, challenges, and opportunities

Huang

et al. 2022

Satell Navig

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The PPP–RTK method, which combines the concepts of Precise of Point Positioning (PPP) and Real-Time Kinematic (RTK), is proposed to provide a centimeter-accuracy positioning service for an unlimited number of users. Recently, the PPP–RTK technique is becoming a promising tool for emerging applications such as autonomous vehicles and unmanned logistics as it has several advantages including high precision, full flexibility, and good privacy. This paper gives a detailed review of PPP–RTK focusing on its implementation methods, recent achievements as well as challenges and opportunities. Firstly, the fundamental approach to implement PPP–RTK is described and an overview of the research on key techniques, such as Uncalibrated Phase Delay (UPD) estimation, precise atmospheric correction retrieval and modeling, and fast PPP ambiguity resolution, is given. Then, the recent efforts and progress are addressed, such as improving the performance of PPP–RTK by combining multi-GNSS and multi-frequency observations, single-frequency PPP–RTK for low-cost devices, and PPP–RTK for vehicle navigation. Also, the system construction and applications based on the PPP–RTK method are summarized. Moreover, the main issues that impact PPP–RTK performance are highlighted, including signal occlusion in complex urban areas and atmosphere modeling in extreme weather events. The new opportunities brought by the rapid development of low-cost markets, multiple sensors, and new-generation Low Earth Orbit (LEO) navigation constellation are also discussed. Finally, the paper concludes with some comments and the prospects for future research.

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Section: Troposphere Modeling Under Complex Terrain and Weather Condi...mentioning

confidence: 99%

Review of PPP–RTK: achievements, challenges, and opportunities

Huang

et al. 2022

Satell Navig

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“…The error sources affecting the accuracy of observations include satellite orbit and clock errors, atmospheric transmission delay, multipath errors, and measurement noise. Among them, the satellite orbit and clock errors and tropospheric delay can be corrected by models (Guo et al, 2017;Ma et al, 2021;Stpniak et al, 2015). Considering that the ionospheric delay is inversely proportional to the square of the signal frequency, the ionospheric delay can be eliminated by the Ionospheric-Free (IF) observation model as follows (Pan et al, 2021).…”

Section: Observation Model Of Precise Point Positioningmentioning

confidence: 99%

A resilient adjustment method to weigh pseudorange observation in precise point positioning

2022

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The accurate weighting of pseudorange observations is important to improve the convergence time and positioning quality of Precise Point Positioning (PPP). Currently, the weight of a pseudorange observation is mainly determined with empirical stochastic models. However, in a complex environment, due to the inability to adapt for the dynamic changes of the user environment, the empirical stochastic models usually cannot reflect the real error level of pseudorange observations. To address this problem, a resilient adjustment method to weigh pseudorange observations is proposed, which constructs the real-time estimation and inflation model for the variance of pseudorange multipath error and measurement noise to replace the empirical stochastic model to determine the weights of pseudorange observations. A set of static and dynamic Global Positioning System (GPS) test data are used to verify the effectiveness of the proposed method. The test results indicate that the proposed real-time estimation model can provide a better representation of the pseudorange accuracy, and the positioning performance of PPP using the real-time estimation model is better than that with the empirical stochastic model. Compared with the optimal empirical stochastic model, the positioning accuracy of PPP with the real-time estimation model is improved by at least 20%, and the convergence time is reduced by at least 50%.

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“…The tropospheric effect on PPP ambiguity has been analyzed (e.g. : Shi and Gao, 2012;Shi and Gao, 2014b;Ma et al 2021). However, this research has some details that make it unique, such as the use of regional Brazilian NWP model; Assessment using free available (source code included) software (RTKLIB) to perform PPP-AR; Assessment of PPP-AR regarding the case of the Brazilian region.…”

Section: Introductionmentioning

confidence: 99%

Assessment of tropospheric modeling on PPP-AR performances under brazilian atmospheric condition

et al. 2022

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In the Global Navigation Satellite System (GNSS), ambiguity resolution (AR) can shorten observation time and increase the positioning quality. The correct tropospheric modeling is intrinsically related to the ability to perform AR. Here, we assessed the influence of different tropospheric correction alternatives on AR for static Precise Point Positioning (PPP) in Brazilian territory. Our goal was to provide directions to users when choosing a suitable tropospheric model for application in PPP-AR under Brazilian atmospheric conditions. Thus, this study was carried out using well-known models such as the Saastamoinen model and the Zenith Tropospheric Delay (ZTD) Estimation and Numerical Weather Prediction (NWP) model from CPTEC/INPE. Six GNSS stations from the Brazilian Network for Continuous Monitoring (RBMC) (BRAZ, UFPR, RNNA, POVE, SMAR, and SAGA) were selected. Different GNSS processing setups were considered for GNSS data registered at selected stations during summer and winter. The assessment was based on a statistical analysis of positioning accuracy during one-hour sessions. The results indicated that such as the ZTD Estimation, the NWP model provides an accuracy of a few centimeters. On the other hand, the Saastamoinen model provided decimeter level accuracy, thus it is not the recommended choice for PPP-AR in the experimental conditions.

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Influence of the inhomogeneous troposphere on GNSS positioning and integer ambiguity resolution

Cited by 14 publications

References 35 publications

Review of PPP–RTK: achievements, challenges, and opportunities

Review of PPP–RTK: achievements, challenges, and opportunities

A resilient adjustment method to weigh pseudorange observation in precise point positioning

Assessment of tropospheric modeling on PPP-AR performances under brazilian atmospheric condition

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