title: The Impact of Estimating High-Resolution Tropospheric Gradients on Multi-GNSS Precise Positioning.
abstract: Benefits from the modernized US Global Positioning System (GPS), the revitalized Russian GLObal NAvigation Satellite System (GLONASS), and the newly-developed Chinese BeiDou Navigation Satellite System (BDS) and European Galileo, multi-constellation Global Navigation Satellite System (GNSS) has emerged as a powerful tool not only in positioning, navigation, and timing (PNT), but also in remote sensing of the atmosphere and ionosphere. Both precise positioning and the derivation of atmospheric parameters can benefit from multi-GNSS observations. In this contribution, extensive evaluations are conducted with multi-GNSS datasets collected from 134 globally-distributed ground stations of the International GNSS Service (IGS) Multi-GNSS Experiment (MGEX) network in July 2016. The datasets are processed in six different constellation combinations, i.e., GPS-, GLONASS-, BDS-only, GPS + GLONASS, GPS + BDS, and GPS + GLONASS + BDS + Galileo precise point positioning (PPP). Tropospheric gradients are estimated with eight different temporal resolutions, from 1 h to 24 h, to investigate the impact of estimating high-resolution gradients on position estimates. The standard deviation (STD) is used as an indicator of positioning repeatability. The results show that estimating tropospheric gradients with high temporal resolution can achieve better positioning performance than the traditional strategy in which tropospheric gradients are estimated on a daily basis. Moreover, the impact of estimating tropospheric gradients with different temporal resolutions at various elevation cutoff angles (from 3° to 20°) is investigated. It can be observed that with increasing elevation cutoff angles, the improvement in positioning repeatability is decreased.
authors.affiliation: Engineering Center of SHMEC for Space Information and GNSS, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. zhouforme@163.com.|Shanghai Key Laboratory of Multidimensional Information Processing, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. zhouforme@163.com.|German Research Centre for Geosciences GFZ, Telegrafenberg, Potsdam 14473, Germany. zhouforme@163.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.affiliation: German Research Centre for Geosciences GFZ, Telegrafenberg, Potsdam 14473, Germany. lxlq109121@gmail.com.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Surveying and Geo-informatics, Tongji University, Shanghai 200092, China. whereareou@126.com.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Li
authors.affiliation: Engineering Center of SHMEC for Space Information and GNSS, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. wchen@sist.ecnu.edu.cn.|Shanghai Key Laboratory of Multidimensional Information Processing, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. wchen@sist.ecnu.edu.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.affiliation: Engineering Center of SHMEC for Space Information and GNSS, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. dndong@cs.ecnu.edu.cn.|Shanghai Key Laboratory of Multidimensional Information Processing, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, China. dndong@cs.ecnu.edu.cn.
authors.forename: Danan
authors.initials: D
authors.lastname: Dong
authors.affiliation: German Research Centre for Geosciences GFZ, Telegrafenberg, Potsdam 14473, Germany. wickert@gfz-potsdam.de.|Faculty VI Planning Building Environment, Technical University of Berlin, Berlin 10623, Germany. wickert@gfz-potsdam.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Wickert
authors.affiliation: German Research Centre for Geosciences GFZ, Telegrafenberg, Potsdam 14473, Germany. schuh@gfz-potsdam.de.|Faculty VI Planning Building Environment, Technical University of Berlin, Berlin 10623, Germany. schuh@gfz-potsdam.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Schuh
keywords: GNSS; elevation cutoff angle; precise point positioning (PPP); temporal resolution; tropospheric gradients