ResourceName
AWESOME receiver system narrowband VLF data
DOI
https://doi.org/10.48322/6t7b-s324
ReleaseDate
2021-05-31 12:34:56.789
RevisionHistory
RevisionEvent
ReleaseDate
2021-05-31 12:34:56.789
Note
Updated to SPASE Version 2.3.2 if needed, Applied quality conntrol for DOI usage, LFB
Description
Most of the data is collected on two air-core loop antennas, oriented orthogonal, to collect the two horizontal components of the magnetic field. The north-south, or N/S antenna is sensitive mostly to waves arriving from the north of from the south direction, meaning it picks up the magnetic field component in the east-west direction. The other antenna is the east-west antenna, which is the opposite.
Narrowband data are the amplitudes and phase of specific frequencies, usually corresponding to VLF transmitters that are used for communications and navigation. Sampling rate is usually either 1 Hz or 50 Hz. They are also useful as a diagnostic of the ionosphere. Most of these transmitters use minimum shift keying (MSK) modulation, and the recording software extracts the amplitude, and the phase is calculated by demodulating the MSK demodulation. Details of the demodulation algorithm and examples of its application can be found in Gross, N. C., Cohen, M. B., Said, R. K., and M. Golkowski, Polarization of Narrowband VLF Transmitter Signals as Ionospheric Diagnostic, JGR, 2018, 901-917, https://doi.org/10.1002/2017ja024907.
Narrowband files available in the WALDO archive are in 24-hour blocks, so the start time of all files is 00:00:00 UT, and the end time is 24:00:00 UT. Even if only a small amount amount of data was recorded on a given day, the file on WALDO will contain 24-hours worth of samples. This is done to make the analysis easier, since all files have the same start time. The raw original data actually starts a new set of files whenever the computer or software reboots, but the archivists made the effort of stitching them together. Where data were not actually recorded, the value will be "NaN" or not a number.
Acknowledgement
DATA USAGE POLICY
The data in the WALDO database have been collected by Stanford University, the Georgia Institute of Technology, and the University of Colorado Denver. Funding has been provided by the United States government under various basic science research grants over many years.
To maximize the benefit of those investments, WALDO data are released without restriction, and can be freely analyzed or published.
The curators of WALDO are Morris Cohen (Georgia Tech) and Mark Golkowski (CU-Denver). We request that the following acknowledgement be added in any publication using data from WALDO: "VLF data are provided by the WALDO database (https://waldo.world), operated jointly by the Georgia Institute of Technology, and the University of Colorado Denver, using data collected from those institutions as well as Stanford University, and has been supported by various US government grants from the NSF, NASA, and the Department of Defense."
If extensive amounts of WALDO data are used in a publication, the curators request, but do not require, to be contacted to discuss the possibility of joint authorship, with the WALDO curators providing help analyzing and interpreting the large dataset.
PublicationInfo
Authors
Cohen, Morris B.; Inan, Umran S.; & Golkowski, Mark A.
PublicationDate
2020-01-01 00:00:00
PublishedBy
Worldwide Archive of Low frequency Data and Observations (WALDO)
Contacts
InformationURL
Name
Worldwide Archive of Low-Frequency Data and Observations (WALDO)
URL
PriorIDs
spase://GBO/NumericalData/AWESOME/VLF/PT0.02S
RepositoryID
AccessURL
Name
Worldwide Archive of Low-Frequency Data and Observations (WALDO) Narrowband Data
URL
Format
MATLAB_4
Acknowledgement
VLF data are provided by the WALDO database (https://waldo.world), operated jointly by the Georgia Institute of Technology, and the University of Colorado Denver, using data collected from those institutions as well as Stanford University, and has been supported by various US government grants from the NSF, NASA, and the Department of Defense.
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