Mapping the ionosphere with millions of phones.

The ionosphere is a layer of weakly ionized plasma bathed in Earth's geomagnetic field extending about 50-1,500 kilometres above Earth. The ionospheric total electron content varies in response to Earth's space environment, interfering with Global Satellite Navigation System (GNSS) signals, resulting in one of the largest sources of error for position, navigation and timing services. Networks of high-quality ground-based GNSS stations provide maps of ionospheric total electron content to correct these errors, but large spatiotemporal gaps in data from these stations mean that these maps may contain errors.

Prospects for meteotsunami detection in earth's atmosphere using GNSS observations.

We study, for the first time, the physical coupling and detectability of meteotsunamis in the earth's atmosphere. We study the June 13, 2013 event off the US East Coast using Global Navigation Satellite System (GNSS) radio occultation (RO) measurements, Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperatures, and ground-based GNSS ionospheric total electron content (TEC) observations. Hypothesizing that meteotsunamis also generate gravity waves (GWs), similar to tsunamigenic earthquakes, we use linear GW theory to trace their dynamic coupling in the atmosphere by comparing theory with observations.

Kalman Filter-based Robust Closed-loop Carrier Tracking of Airborne GNSS Radio-Occultation Signals.

GNSS radio occultation (RO) signals have been demonstrated as a viable means to retrieve atmospheric profiles. Current GNSS-RO observations rely on open-loop (OL) processing of the signals, especially for signals propagating through the lower troposphere. The reason is that GNSS signals at low elevations are adversely affected by multipath effects due to propagation through lower troposphere structures and reflections and scattering from the Earth surface.