A real-time cycle slip repair method using the multi-epoch geometry-based model


Unrepaired cycle slips in carrier phase measurements will result in re-initializing integer ambiguities, during which positioning accuracy will be compromised. However, the issue of cycle slip fixing has yet to be completely solved, which impedes the realization of continuous high-precision positioning, especially in real-time precise point positioning applications. Traditional cycle slip (detection and) repair methods only use adjacent epochs to estimate cycle slips in real-time processing. Research indicates that using multiple epochs in the time-differencing model of cycle slip estimation could significantly improve cycle slip repair in real-time processing. A multi-epoch geometry-based cycle slip repair method is introduced, and it can also be implemented in real-time processing. A comparative study, including the theoretical model strength and real repairing rates for static and kinematic datasets, is performed under identical settings. The result demonstrates that a considerable number of the cycle slips unrepaired by the existing methods can be fixed by using the enhanced new method. In a low sampling rate static experiment, the average repair rates of the cycle slips unrepaired by the single-epoch geometry-based method and multi-epoch geometry-free method can be improved from 98.2% and 37.6% respectively to 99.3% by the new method using 4 epochs. In kinematic experiments, significant improvement is observed in shipborne, land-based, and airborne experiments using the new method compared with the existing methods.

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Data Availability

The datasets of the IGS stations can be accessed via ftp://igs.org/pub/. The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.


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The authors would like to thank two anonymous reviewers for their valuable comments which helped to improve the manuscript. We would also like to thank Dr. Xiaowen Luo for providing the kinematic dataset, and the IGS station providers are also acknowledged.

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Correspondence to Wenhao Zhang.

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Zhang, W., Wang, J. A real-time cycle slip repair method using the multi-epoch geometry-based model. GPS Solut 25, 60 (2021). https://doi.org/10.1007/s10291-021-01098-y

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  • GNSS
  • Cycle slip repair
  • Precise point positioning
  • Real-time processing