Generation of Klobuchar Coefficients Based on IGS GIM for Regionally Optimized Ionospheric Correction in GNSS Positioning

초록

Highlights What are the main findings? A novel method to estimate regionally optimized Klobuchar coefficients using only IGS Global Ionosphere Map (GIM) data was developed, preserving computational simplicity. The regional Klobuchar models based on STEC (KRS) and VTEC (KRV) achieved significant reductions in ionospheric delay error, outperforming the standard GPS Klobuchar model by over 50%. What is the implication of the main finding? The proposed methodology enables practical near-real-time regional ionospheric correction for GNSS positioning without relying on extensive GNSS station networks or complex data processing. This approach provides an effective framework for improving ionospheric delay correction in existing GNSS systems and can be adapted for other regional navigation systems.Highlights What are the main findings? A novel method to estimate regionally optimized Klobuchar coefficients using only IGS Global Ionosphere Map (GIM) data was developed, preserving computational simplicity. The regional Klobuchar models based on STEC (KRS) and VTEC (KRV) achieved significant reductions in ionospheric delay error, outperforming the standard GPS Klobuchar model by over 50%. What is the implication of the main finding? The proposed methodology enables practical near-real-time regional ionospheric correction for GNSS positioning without relying on extensive GNSS station networks or complex data processing. This approach provides an effective framework for improving ionospheric delay correction in existing GNSS systems and can be adapted for other regional navigation systems.Abstract A practical methodology for estimating regionally optimized Klobuchar coefficients using only International GNSS Service (IGS) Global Ionosphere Map (GIM) data is proposed. The method preserves computational simplicity, enabling near-real-time corrections suitable for accurate GNSS positioning. Utilizing both slant and vertical total electron content (STEC and VTEC) values extracted from GIM as inputs to estimate eight Klobuchar coefficients, robust parameter sets were obtained. Root mean square error (RMSE) analysis was used to compare these models to the standard Klobuchar model. Comprehensive performance evaluations using STEC-derived parameters, encompassing both seasonal and spatial analyses across South Korea, demonstrated significant reductions in ionospheric delay errors, with improvements reaching up to 57% compared to the conventional Klobuchar model. The far less computationally intensive VTEC-based model was applied over a wider region with 120 grid points. Continuous testing of this model over an entire year confirmed consistent enhancements in correction accuracy every day, demonstrating stable performance throughout the period. The developed regional Klobuchar models were further validated indirectly through satellite positioning performance, demonstrating daily RMSE improvements over the standard Klobuchar model ranging from 17.3% to 44.6%.

키워드