Altitude dependent empirical modeling of the topside ionosphere and plasmasphere using GPS- TEC from Swarm, GRACE-FO and the Sentinel satellites.
<p>Slant Total Electron Content (sTEC) measurements can be obtained by dual-frequency GPS<br>onboard Low Earth Orbiting (LEO) satellites. Within the last few years, a fleet of LEO Satellites at<br>altitudes ranging from 450 km (Swarm A/C) to 815 km (Sentinel 3) became operational. With<br>Swarm B, the recently launched GRACE-FO, and the Sentinel 1 and 2 satellites orbiting at<br>intermediate altitudes, we gain insight into the altitude dependent profile of the topside ionosphere<br>and plasmasphere.<br>We make use of this constellation to estimate a global three dimensional model of the electron<br>density distribution and will also carefully asses the impact of different profile functions, geometry-<br>free phase center variation maps and the P1-P2 receiver biases. Since the absolute value of the P1-<br>P2 biases are generally unknown, we focus on a consistent estimation for the whole LEO<br>constellation.<br>We will present first results for selected months in 2019 and investigate the day to day variability of<br>the topside ionosphere and plasmasphere. We also intend to make use of COSMIC-2 data to<br>improve local time coverage in equatorial regions.</p>