VLA Ionospheric and Transient Experiment (VLITE) Ionosphere

The ionosphere analysis portion of VLITE is dedicated to the study of fine-scale (~1-10 km) ionosphere dynamics and the relationship to larger structures (hundreds of km). The VLA low-band systems have virtually unmatched sensitivity to fluctuations in the ionosphere total electron content (TEC), the integrated density of free electrons along a line of sight. When observing a bright cosmic source, these systems can be used to characterize TEC fluctuations more than two orders of magnitude weaker than those detectable with similar GPS-based methods. Such fluctuations are prevalent on smaller scales, making the VLA an excellent instrument for probing fine-scale ionosphere dynamics. Many continuously operating GPS receivers within New Mexico will also be used to simultaneously study larger-scale fluctuations. The (nearly) continuous data stream that will be yielded by VLITE, when combined with this GPS data, will constitute a singular data set for the study of coupling mechanisms among fine-, medium-, and large-scale ionosphere dynamics. In addition, such a continuous flow of data will allow for the characterization of the fine-scale ionosphere response to relatively rare atmospheric and/or seismic events such as large storms, earthquakes, and explosions that would be missed by proposal-based, low-band observing.

• Extract good visibility phases from the raw data, while flagging obviously aberrant data.
• Unwrap the phase time series and de-trend to remove slowly varying instrumental and/or source contributions.
• Determine and remove contributions from baseline-based errors.
• Use final δTEC time series to compute TEC gradients.

Copyright © 2009 Associated Universities, Inc.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.