Accurate Estimation of Height and Zonal Drift Velocity of Ionospheric Irregularities Using Two Pairs of Receivers and BeiDou Geostationary Satellites

This article presents a new method for accurately estimating the height and zonal drift velocity of ionospheric irregularities, based on crossed signal paths from two BeiDou geostationary satellites to two ground-based receivers. The ratio of distances between different signal paths varies with altitude, and irregularities' height can be identified according to observed arrival times of ionospheric irregularities among signal paths. The proposed method is an improvement of the conventional way with an assumed fixed height of about 350 km for the nocturnal ionospheric irregularities. We present two cases with estimated irregularities heights of 284 and 403 km, respectively. Accordingly, the calculated zonal drift velocities and the apex height of the irregularities are significantly different as well. Observations from the nearby Hainan Coherent Scatter Phased Array Radar (HCOPAR) radar validate the estimated height and velocity, though discrepancies existing in terms of the arrival times of ionospheric irregularities observed by the two kinds of instruments. It further highlights the necessity of this method to probe global navigation satellite system (GNSS)-sensitive irregularities using the disturbed GNSS signals per se.