Ionospheric electron content prediction from SERIES/GPS data

Total electron contents along arbitrary lines-of-sight are derived from dual band SERIES P-code data. At present, in a normal observing session, five Global Positioning Satellites (GPS) can be observed for a time interval of 5 h. A SERIES observing session consists of about 300 line-of-sight measurements. Transmitter offsets are different for each satellite and no reliable a priori data can be obtained at present. The electron content and the satellite offsets are estimated simultaneously by a least squares procedure using a simple empirical model. The present accuracy of this technique is estimated to be 6 x 10 to the 16th el/sq m. The results are compared with Faraday rotation measurements. The method may be used for local or global ionospheric content monitoring.