Cycle slip detection and repair for undifferenced GPS observations under high ionospheric activity

Changsheng Cai, Zhizhao Liu, Pengfei Xia, Wujiao Dai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

139 Citations (Scopus)


We develop a new approach for cycle slip detection and repair under high ionospheric activity using undifferenced dual-frequency GPS carrier phase observations. A forward and backward moving window averaging (FBMWA) algorithm and a second-order, time-difference phase ionospheric residual (STPIR) algorithm are integrated to jointly detect and repair cycle slips. The FBMWA algorithm is proposed to detect cycle slips from the widelane ambiguity of Melbourne-Wübbena linear combination observable. The FBMWA algorithm has the advantage of reducing the noise level of widelane ambiguities, even if the GPS data are observed under rapid ionospheric variations. Thus, the detection of slips of one cycle becomes possible. The STPIR algorithm can better remove the trend component of ionospheric variations compared to the normally used first-order, time-difference phase ionospheric residual method. The combination of STPIR and FBMWA algorithms can uniquely determine the cycle slips at both GPS L1and L2frequencies. The proposed approach has been tested using data collected under different levels of ionospheric activities with simulated cycle slips. The results indicate that this approach is effective even under active ionospheric conditions.
Original languageEnglish
Pages (from-to)247-260
Number of pages14
JournalGPS Solutions
Issue number2
Publication statusPublished - 1 Jan 2013


  • Cycle slip
  • Forward and backward moving window averaging
  • GPS
  • Melbourne-Wübbena linear combination
  • Second-order
  • Time-difference phase ionospheric residual

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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