Estimation of Total Electron Content Using Single Frequency Weighted Observations for Esfahan Province

Abstract

One of the major error sources in the global positioning system (GPS) is ionospheric delay (refraction). This delay is frequency dependent and therefore can be removed by dual frequency receivers. Using eight coefficients transmitted as part of the navigation message a correction can be provided for single frequency users called the Klobuchar model. This model is expected to remove up to 50% of ionospheric delay. On the other hand all receivers cannot recover coefficients. This paper is a report on our attempt at the GPS site of Esfahan University to model the zenith ionospheric delay from weighted observation of the L1 code and carrier phase, made with a 12-channel Leica System 500 receiver. The results will be compared with IGS and Klobuchar model estimates.