Articles | Volume 35, issue 1
Ann. Geophys., 35, 97–106, 2017

Special issue: The 14th International Symposium on Equatorial Aeronomy

Ann. Geophys., 35, 97–106, 2017

Regular paper 13 Jan 2017

Regular paper | 13 Jan 2017

Scintillation measurements at Bahir Dar during the high solar activity phase of solar cycle 24

Martin Kriegel1, Norbert Jakowski1, Jens Berdermann1, Hiroatsu Sato1, and Mogese Wassaie Mersha2 Martin Kriegel et al.
  • 1German Aerospace Center (DLR), Institute of Communications and Navigation, Kalkhorstweg 53, 17235 Neustrelitz, Germany
  • 2Washera Geospace and Radar Science Laboratory, Bahir Dar University, Bahir Dar, Ethiopia

Abstract. Small-scale ionospheric disturbances may cause severe radio scintillations of signals transmitted from global navigation satellite systems (GNSSs). Consequently, small-scale plasma irregularities may heavily degrade the performance of current GNSSs such as GPS, GLONASS or Galileo. This paper presents analysis results obtained primarily from two high-rate GNSS receiver stations designed and operated by the German Aerospace Center (DLR) in cooperation with Bahir Dar University (BDU) at 11.6° N, 37.4° E. Both receivers collect raw data sampled at up to 50 Hz, from which characteristic scintillation parameters such as the S4 index are deduced.

This paper gives a first overview of the measurement set-up and the observed scintillation events over Bahir Dar in 2015. Both stations are located close to one another and aligned in an east–west, direction which allows us to estimate the zonal drift velocity and spatial dimension of equatorial ionospheric plasma irregularities. Therefore, the lag times of moving electron density irregularities and scintillation patterns are derived by applying cross-correlation analysis to high-rate measurements of the slant total electron content (sTEC) along radio links between a GPS satellite and both receivers and to the associated signal power, respectively. Finally, the drift velocity is derived from the estimated lag time, taking into account the geometric constellation of both receiving antennas and the observed GPS satellites.