Refining the Klobuchar ionospheric coefficients based on GPS observations

A method is proposed to improve the GPS broadcast ionospheric time-delay correction accuracy, using GPS observation data from the globally distributed international GNSS service (IGS) observation stations and the Crust Movement Observation Network of China (CMONOC). A new set of Klobuchar-Self coefficients can be estimated using the method. Primary results demonstrate that the refined Klobuchar-Self coefficients developed may provide better ionospheric delay corrections for single-frequency GPS receivers and improve standard single point positioning accuracies.