Abstract
The tropospheric delay is one of the main error sources that degrades the accuracy of Global Navigation Satellite Systems (GNSS) Single Point Positioning (SPP). Although an empirical model is usually applied for correction and thereby to improve the positioning accuracy, the residual tropospheric delay is still drowned in measurement noise, and cannot be further compensated by parameter estimation. How much this type of residual error would sway the SPP positioning solutions on a global scale are still unclear. In this paper, the biases on SPP solutions introduced by the residual tropospheric delay when using nine conventionally Zenith Tropospheric Delay (ZTD) models are analyzed and discussed, including Saastamoinen+norm/Global Pressure and Temperature (GPT)/GPT2/GPT2w/GPT3, University of New Brunswick (UNB)3/UNB3m, European Geostationary Navigation Overlay System (EGNOS) and Vienna Mapping Functions (VMF)3 models. The accuracies of the nine ZTD models, as well as the SPP biases caused by the residual ZTD (dZTD) after model correction are evaluated using International GNSS Service (IGS)-ZTD products from around 400 globally distributed monitoring stations. The seasonal, latitudinal, and altitudinal discrepancies are analyzed respectively. The results show that the SPP solution biases caused by the dZTD mainly occur on the vertical direction, nearly to decimeter level, and significant discrepancies are observed among different models at different geographical locations. This study provides references for the refinement and applications of the nine ZTD models for SPP users.
Highlights
Due to the high operational efficiency and algorithm simplicity, pseudorange-basedSingle Point Positioning (SPP) is still the most popular Global Navigation Satellite Systems (GNSS) positioning technology for custom-grade navigation where meter-level positioning accuracy is sufficient [1]
The results show that the SPP solution biases caused by the dZTD mainly occur on the vertical direction, nearly to decimeter level, and significant discrepancies are observed among different models at different geographical locations
The residual tropospheric delay after model correction will be further estimated in Precise Point Positioning (PPP) and NetworkReal Time Kinematic (NRTK) applications, so as to mitigate the biases projecting to positioning
Summary
Due to the high operational efficiency and algorithm simplicity, pseudorange-basedSingle Point Positioning (SPP) is still the most popular Global Navigation Satellite Systems (GNSS) positioning technology for custom-grade navigation where meter-level positioning accuracy is sufficient [1]. One of the major error sources that degrades the SPP accuracy is the signal transmission delay caused by the troposphere [2]. The so-called tropospheric delay varies from about 2 m at the zenith to 20 m at lower elevation angles between receiver and satellite [3]. An empirical model is applied to mitigate the tropospheric delay and therewith to improve the positioning accuracy [4,5]. The residual tropospheric delay after model correction will be further estimated in PPP and NRTK applications, so as to mitigate the biases projecting to positioning. In SPP, the residual tropospheric delay is drowned in measurement noise, and cannot be further compensated by parameter estimation. It is necessary to assess the biases produced by the residual tropospheric delay on SPP
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
