Approach for near‐real‐time prediction of ionospheric delay using Klobuchar‐like coefficients for Indian region

Abstract

Currently, global positioning system (GPS) satellites transmit the Klobuchar coefficients to estimate ionospheric delay for the single-frequency users. These coefficients are broadcast to the users on the basis of seasonal ionospheric variations and average solar flux. In low-latitude Indian region, prediction of the delay using these coefficient is not accurate because of complex behaviour of the ionospheric. In this study, new Klobuchar-like cofficients are generated using regional total electron content data collected from the 18 stations in Indian. Using these coefficients, a novel approach for near-real-time prediction of the ionospheric delay (for every 5 min) is proposed. This approach provides the opportunity to generate the Klobuchar-like coefficients using shorter data sets (1 day) rather than using long-term statistics of several years, as done in the generation of GPS broadcast Klobuchar coefficients. Performance of the prediction is evaluated for the geomagnetic quiet (Ap index 300) days of 2005 and 2007. Prediction accuracy is significantly improved using the single-frequency users of the Regional Navigational Satellite Systems, such as the proposed Indian Regional Navigation Satellite System.