HPDE.io

ISIS1 Swept-Frequency Sounder

ResourceID
spase://SMWG/Instrument/ISIS1/SFS

Description

The ISIS 1 (International Satellites for Ionospheric Studies) Swept-Frequency Sounder measured the
ionospheric electron density in the altitude range 300 to 3500 km, and provided correlative data for the other
ISIS 1 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 19 or 29 s, and one of six selected frequencies was also used for sounding
for a few seconds during each 19- or 29-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.

View XML | View JSON | Edit

Details

Version:2.2.0

Instrument

ResourceID
spase://SMWG/Instrument/ISIS1/SFS
ResourceHeader
ResourceName
ISIS1 Swept-Frequency Sounder
AlternateName
Topside Sounder
ReleaseDate
2019-05-05 12:34:56Z
Description

The ISIS 1 (International Satellites for Ionospheric Studies) Swept-Frequency Sounder measured the
ionospheric electron density in the altitude range 300 to 3500 km, and provided correlative data for the other
ISIS 1 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 19 or 29 s, and one of six selected frequencies was also used for sounding
for a few seconds during each 19- or 29-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
RolePerson
1.PrincipalInvestigatorspase://SMWG/Person/James.H.Whitteker
InformationURL
Name
NSSDC's Master Catalog
URL
https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1969-009A-01
Description

Information about the Sweep-Frequency Sounder on ISIS 1

InstrumentType
Sounder
InvestigationName
Swept-Frequency Sounder on ISIS 1
ObservatoryID
spase://SMWG/Observatory/ISIS1