A modified carrier-to-code leveling method for retrieving ionospheric observables and detecting short-term temporal variability of receiver differential code biases

  • Baocheng Zhang
  • Peter J. G. Teunissen
  • Yunbin Yuan
  • Xiao Zhang
  • Min Li
Original Article


Sensing the ionosphere with the global positioning system involves two sequential tasks, namely the ionospheric observable retrieval and the ionospheric parameter estimation. A prominent source of error has long been identified as short-term variability in receiver differential code bias (rDCB). We modify the carrier-to-code leveling (CCL), a method commonly used to accomplish the first task, through assuming rDCB to be unlinked in time. Aside from the ionospheric observables, which are affected by, among others, the rDCB at one reference epoch, the Modified CCL (MCCL) can also provide the rDCB offsets with respect to the reference epoch as by-products. Two consequences arise. First, MCCL is capable of excluding the effects of time-varying rDCB from the ionospheric observables, which, in turn, improves the quality of ionospheric parameters of interest. Second, MCCL has significant potential as a means to detect between-epoch fluctuations experienced by rDCB of a single receiver.


Global positioning system (GPS) Ionosphere Vertical total electron content (vTEC) Receiver differential code bias (rDCB) Modified carrier-to-code leveling (MCCL) 



This work was partially funded by the National key Research Program of China “Collaborative Precision Positioning Project” (No. 2016YFB0501900) and the National Natural Science Foundation of China (Nos. 41604031, 41774042, 41621091). The first author is supported by the CAS Pioneer Hundred Talents Program. The third author acknowledges LU JIAXI International team program supported by the K.C. Wong Education Foundation and CAS. Special thanks go to Dr. Francisco Azpilicueta for providing the data set used in this study.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and GeophysicsChinese Academy of SciencesWuhanChina
  2. 2.Global Navigation Satellite System (GNSS) Research CentreCurtin UniversityPerthAustralia
  3. 3.Geoscience and Remote SensingDelft University of TechnologyDelftThe Netherlands

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