title: Smart Device-Supported BDS/GNSS Real-Time Kinematic Positioning for Sub-Meter-Level Accuracy in Urban Location-Based Services.
abstract: Using mobile smart devices to provide urban location-based services (LBS) with sub-meter-level accuracy (around 0.5 m) is a major application field for future global navigation satellite system (GNSS) development. Real-time kinematic (RTK) positioning, which is a widely used GNSS-based positioning approach, can improve the accuracy from about 10-20 m (achieved by the standard positioning services) to about 3-5 cm based on the geodetic receivers. In using the smart devices to achieve positioning with sub-meter-level accuracy, a feasible solution of combining the low-cost GNSS module and the smart device is proposed in this work and a user-side GNSS RTK positioning software was developed from scratch based on the Android platform. Its real-time positioning performance was validated by BeiDou Navigation Satellite System/Global Positioning System (BDS/GPS) combined RTK positioning under the conditions of a static and kinematic (the velocity of the rover was 50-80 km/h) mode in a real urban environment with a SAMSUNG Galaxy A7 smartphone. The results show that the fixed-rates of ambiguity resolution (the proportion of epochs of ambiguities fixed) for BDS/GPS combined RTK in the static and kinematic tests were about 97% and 90%, respectively, and the average positioning accuracies (RMS) were better than 0.15 m (horizontal) and 0.25 m (vertical) for the static test, and 0.30 m (horizontal) and 0.45 m (vertical) for the kinematic test.
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. wangliang115@mails.ucass.ac.cn.|University of Chinese Academy of Sciences, Beijing 100049, China. wangliang115@mails.ucass.ac.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. lizishen@aoe.ac.cn.|Key Laboratory for Urban Geomatics of National Administration of Surveying, Mapping and Geoinformation, Beijing 100044, China. lizishen@aoe.ac.cn.
authors.forename: Zishen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. zhaojj@aoe.ac.cn.|University of Chinese Academy of Sciences, Beijing 100049, China. zhaojj@aoe.ac.cn.
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. zhoukai@aoe.ac.cn.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. wangzhiyu15@mails.ucas.ac.cn.|University of Chinese Academy of Sciences, Beijing 100049, China. wangzhiyu15@mails.ucas.ac.cn.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China. yuanh@aoe.ac.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Yuan
keywords: BeiDou navigation satellite system (BDS); global navigation satellite system (GNSS); location-based services (LBS); real-time kinematic (RTK); smart devices