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

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 (A_p index <;50) and severely disturbed (A_p 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.