title: A Unified Model for BDS Wide Area and Local Area Augmentation Positioning Based on Raw Observations.
abstract: In this study, a unified model for BeiDou Navigation Satellite System (BDS) wide area and local area augmentation positioning based on raw observations has been proposed. Applying this model, both the Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) service can be realized by performing different corrections at the user end. This algorithm was assessed and validated with the BDS data collected at four regional stations from Day of Year (DOY) 080 to 083 of 2016. When the users are located within the local reference network, the fast and high precision RTK service can be achieved using the regional observation corrections, revealing a convergence time of about several seconds and a precision of about 2-3 cm. For the users out of the regional reference network, the global broadcast State-Space Represented (SSR) corrections can be utilized to realize the global PPP service which shows a convergence time of about 25 min for achieving an accuracy of 10 cm. With this unified model, it can not only integrate the Network RTK (NRTK) and PPP into a seamless positioning service, but also recover the ionosphere Vertical Total Electronic Content (VTEC) and Differential Code Bias (DCB) values that are useful for the ionosphere monitoring and modeling.
authors.affiliation: National Time Service Center, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. turui-2004@126.com.|Key Laboratory of Precision Navigation and Timing Technology, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. turui-2004@126.com.|College of earth sciences, University of Chinese Academy of Sciences, Yu Quan Road, Beijing 100049, China. turui-2004@126.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Tu
authors.affiliation: National Time Service Center, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. zhangruiwkk@163.com.|Key Laboratory of Precision Navigation and Timing Technology, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. zhangruiwkk@163.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Germany Research Center for Geosciences, Telegrafenberg, Potsdam 14473, Germany. cuixian@gfz-potsdam.de.
authors.forename: Cuixian
authors.initials: C
authors.lastname: Lu
authors.affiliation: National Time Service Center, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. zpf.333@163.com.|College of earth sciences, University of Chinese Academy of Sciences, Yu Quan Road, Beijing 100049, China. zpf.333@163.com.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: National Time Service Center, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. jinhailiu15@163.com.|College of earth sciences, University of Chinese Academy of Sciences, Yu Quan Road, Beijing 100049, China. jinhailiu15@163.com.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Liu
authors.affiliation: National Time Service Center, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. lxc@ntsc.ac.cn.|Key Laboratory of Precision Navigation and Timing Technology, Chinese Academy of Sciences, Shu Yuan Road, Xi'an 710600, China. lxc@ntsc.ac.cn.|College of earth sciences, University of Chinese Academy of Sciences, Yu Quan Road, Beijing 100049, China. lxc@ntsc.ac.cn.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Lu
keywords: BDS; PPP/RTK; ambiguity resolution; local augmentation positioning