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ISIS2 Swept-Frequency Sounder

ResourceID
spase://SMWG/Instrument/ISIS2/SFS

Description

The ISIS 2 (International Satellites for Ionospheric Studies) Swept-Frequency Sounder measured the ionospheric electron density in the altitude range 300 to 1400 km, and provided correlative data for the other ISIS 2 experiments, particularly those measuring ionospheric parameters. The ionosonde was a radio transmitter that recorded the time delay between a transmitted and returned radio-frequency pulse. A continuum of frequencies between 0.1 and 20 MHz was sampled every 14 or 21 s, and one of six selected frequencies was also used for sounding for a few seconds during each 14- or 21-s period. In addition to the sweep- and fixed-frequency modes of operation, a mixed mode was available in which the transmitter frequency was fixed at one of six possible frequencies while the receiver swept. Several virtual-range (delay-time) traces resulting from ground reflections, plasma resonances, birefringence of the ionosphere, nonvertical propagation, etc., were normally observed.

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Details

Version:2.1.0

Instrument

ResourceID
spase://SMWG/Instrument/ISIS2/SFS
ResourceHeader
ResourceName
ISIS2 Swept-Frequency Sounder
AlternateName
Topside Sounder
ReleaseDate
2019-05-05 12:34:56Z
Description

The ISIS 2 (International Satellites for Ionospheric Studies) Swept-Frequency Sounder measured the ionospheric electron density in the altitude range 300 to 1400 km, and provided correlative data for the other ISIS 2 experiments, particularly those measuring ionospheric parameters. The ionosonde was a radio transmitter that recorded the time delay between a transmitted and returned radio-frequency pulse. A continuum of frequencies between 0.1 and 20 MHz was sampled every 14 or 21 s, and one of six selected frequencies was also used for sounding for a few seconds during each 14- or 21-s period. In addition to the sweep- and fixed-frequency modes of operation, a mixed mode was available in which the transmitter frequency was fixed at one of six possible frequencies while the receiver swept. Several virtual-range (delay-time) traces resulting from ground reflections, plasma resonances, birefringence of the ionosphere, nonvertical propagation, etc., were normally observed.

Contacts
RolePersonStartDateStopDateNote
1.PrincipalInvestigatorspase://SMWG/Person/James.H.Whitteker
InformationURL
Name
NSSDC's Master Catalog
URL
Description

Information about the Swept-Frequency Sounder on ISIS 2

InstrumentType
Sounder
InvestigationName
Swept-Frequency Sounder on ISIS 2
ObservatoryID