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ISIS 1 Topside Sounder Ionograms

ResourceID
spase://NASA/NumericalData/ISIS1/SFS/Ionogram/PT29S

Description

These ionograms were digitized from the original ISIS-1 7-track analog telemetry tapes using the facilities of the former Data Evaluation Laboratory at the NASA/GSFC. This data restoration project is headed by Dr. R.F. Benson (NASA/GSFC). Ionograms were digitized at the rate of 40,000 16-bit samples/sec. This sample rate is higher than the Nyquist frequency of 30 kHz. The sample frequency of 40 kHz provides a measurement every 25 microseconds corresponding to an apparent range (c*t/2) interval of 3.75 km. Each ionogram consists of a fixed-frequency and and a swept-frequency portion. The time resolution between ionograms is typically 29 seconds.

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Details

Version:2.2.9

NumericalData

ResourceID
spase://NASA/NumericalData/ISIS1/SFS/Ionogram/PT29S
ResourceHeader
ResourceName
ISIS 1 Topside Sounder Ionograms
AlternateName
ISIS-1 Topside Sounder Ionogram CDFs at NASA's CDAWeb
ReleaseDate
2020-07-07 21:14:41Z
Description

These ionograms were digitized from the original ISIS-1 7-track analog telemetry tapes using the facilities of the former Data Evaluation Laboratory at the NASA/GSFC. This data restoration project is headed by Dr. R.F. Benson (NASA/GSFC). Ionograms were digitized at the rate of 40,000 16-bit samples/sec. This sample rate is higher than the Nyquist frequency of 30 kHz. The sample frequency of 40 kHz provides a measurement every 25 microseconds corresponding to an apparent range (c*t/2) interval of 3.75 km. Each ionogram consists of a fixed-frequency and and a swept-frequency portion. The time resolution between ionograms is typically 29 seconds.

Acknowledgement
Users please acknowledge the Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center, ISIS-1 SFS instrument Principal Investigator J. H. Whitteker and ISIS Data-Restoration project lead Robert F. Benson.
Contacts
RolePerson
1.PrincipalInvestigatorspase://SMWG/Person/James.H.Whitteker
2.GeneralContactspase://SMWG/Person/Robert.F.Benson
3.GeneralContactspase://SMWG/Person/Dieter.K.Bilitza
InformationURL
Name
ISIS/Alouette Topside Sounder Data Restoration Project
URL
https://nssdc.gsfc.nasa.gov/space/isis/isis-status.html
Description

ISIS/Alouette page maintained by NASA GSFC with science and instrument descriptions, data access, software, and publication lists

Language
en
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 experiment on ISIS-1.

PriorIDs
spase://VWO/NumericalData/ISIS1/SFS/ISIS1_Ionogram_CDF_PT29S
spase://VWO/NumericalData/ISIS1/SFS/Ionogram.PT29S
spase://VSPO/NumericalData/ISIS1/SFS/Ionogram/PT29S
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
Availability
Online
AccessRights
Open
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_cdf/isis1/
Description

FTP access to repository of ISIS-1 Ionograms in CDF format at NASA CDAWeb. The CDF files are organized by ground station, where each ground station is represented by a three letter ID and a two-digit code. The full names for each station are provided at https://nssdc.gsfc.nasa.gov/space/isis/isis-table1-new.html A merged data set, independent of the ground stations, is in preparation.

Language
en
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_cdf/isis1/
Description

HTTPS access to repository of ISIS-1 Ionograms in CDF format at NASA CDAWeb

Language
en
AccessURL
Name
CDAWeb
URL
https://cdaweb.sci.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=I1_AV_ALL&index=sp_phys
ProductKey
I1_AV_ALL
Description

Repository of ISIS-1 data in CDF format at NASA CDAWeb, accessible via web interface.

Language
en
AccessURL
Name
Fairbanks, Alaska
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Fairbanks/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Fairbanks, AK: ULA, Latitude 65, Longitude 212

AccessURL
Name
Kashima, Japan
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Kashima/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Kashima, Japan: KSH, Latitude 36, Longitude 141

AccessURL
Name
Kerguelen Island, France
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/KerguelenIsland/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Kerguelen Island, France: KER, Latitude -49, Longitude 70

AccessURL
Name
Kwajalein, Marshall Islands
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Kwajalein/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Kwajalein, Marshall Islands: KWA, Latitude 9, Longitude 168

AccessURL
Name
Orroral, Australia
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Orroral/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Orroral, Australia: ORR, Latitude -36, Longitude 149

AccessURL
Name
Ottawa, QC, Canada
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Ottawa/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Ottawa, QC, Canada: OTT, Latitude 45, Longitude 284

AccessURL
Name
Ottawa, QC, Canada, Version 2
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Ottawa/Corrected/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Ottawa, QC, Canada, Version 2: OTT, Latitude 45, Longitude 284

AccessURL
Name
Ouagadougou, Burkina Faso
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Ouagadougou/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Ouagadougou, Burkina Faso: ODG, Latitude 14, Longitude 359

AccessURL
Name
Quito, Equador
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Quito/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Quito, Equador: QUI, Latitude -1, Longitude 281

AccessURL
Name
Resolute Bay, NU, Canada
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/ResoluteBay/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Resolute Bay, NU, Canada: RES, Latitude 75, Longitude 265

AccessURL
Name
Santiago, Chile
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Santiago/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Santiago, Chile: SNT, Latitude -33, Longitude 298

AccessURL
Name
Sodankyla, Finland
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Sodankyla/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Sodankyla, Finland: SOD, Latitude 67, Longitude 27

AccessURL
Name
Tromso, Norway
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Tromso/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Tromso, Norway: TRO, Latitude 70, Longitude 19

AccessURL
Name
Winkfield, United Kingdom
URL
https://hpde.io/NASA/NumericalData/ISIS1/SFS/AverageIonogram/Winkfield/PT29S
Description

ISIS-1 Topside Sounder Average Ionogram over Winkfield, United Kingdom: WNK, Latitude 51, Longitude 359

Format
CDF
Encoding
None
Acknowledgement
Users please acknowledge the Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center, ISIS-1 SFS instrument Principal Investigator J. H. Whitteker and ISIS Data-Restoration project lead Robert F. Benson.
ProcessingLevel
Calibrated
InstrumentIDs
spase://SMWG/Instrument/ISIS1/SFS
MeasurementType
Waves.Active
MeasurementType
Spectrum
TemporalDescription
TimeSpan
StartDate
1969-01-30 14:50:12Z
StopDate
1983-12-30 15:19:33Z
Note
The cadence is 17 or 29 s for ionograms that have a swept-frequency portion from 0.1 to 10.0 MHz and 0.1 to 20 MHz, respectively. NOTE: for ISIS2 the appropriate values are 14 and 22.5 s, for 0.1 to 10.0 MHz and 0.1 to 20 MHz ionograms, respectively.
Cadence
PT24S
SpectralRange
RadioFrequency
ObservedRegion
Earth.Magnetosphere
ObservedRegion
Earth.Magnetosphere.Polar
ObservedRegion
Earth.NearSurface.AuroralRegion
ObservedRegion
Earth.NearSurface.PolarCap
ObservedRegion
Earth.NearSurface.Ionosphere
ObservedRegion
Earth.NearSurface.Ionosphere.Topside
Keywords
Ionogram
topside sounder
fixed- and swept-frequency sounder
topside ionosphere
ionospheric reflections
ground reflections
ionospheric echoes
ground echoes
ducted echoes
wave scattering
field-aligned irregularities
FAI
plasma resonance
plasma waves
AKR
solar type III bursts
upper-hybrid noise band
Parameter #1
Name
satellite ID
ParameterKey
satellite
Description

sat.-ID: 1=AL1, 2=AL2, 3=ISIS1, 4=ISIS2

Support
SupportQuantity
Other
Parameter #2
Name
telemetry station code
ParameterKey
station_id
Description

two-digit telemetry station code

Support
SupportQuantity
Other
Parameter #3
Name
transmitter power code
ParameterKey
power_code
Description

trans. power code: 1=Prim(400W) 2=Sec(400W)

Support
SupportQuantity
Other
Parameter #4
Name
sounder/receiver code
ParameterKey
s/r_code
Description

sounder/receiver code: 0=off, 1=on

Support
SupportQuantity
Other
Parameter #5
Name
pulse per second code
ParameterKey
pps_code
Description

pulse per second code: 0= 30 pps, 1= 60 pps

Support
SupportQuantity
Other
Parameter #6
Name
DMODE code
ParameterKey
DMODE
Description

DMODE (transm. on/off for alternate frame pairs): 0=off, 1=on

Support
SupportQuantity
Other
Parameter #7
Name
GMODE code
ParameterKey
GMODE
Description

GMODE (transmission of alternate frames of fixed-frequency ionograms and normal combined fixed- and swept-frequency ionograms): 0=off, 1=on

Support
SupportQuantity
Other
Parameter #8
Name
sounder mixed mode
ParameterKey
mixed_mode
Description

sounder mixed mode (transmission at a fixed-frequency while the sounder receiver sweeps over swept-frequency range): 0=off, 1=on

Support
SupportQuantity
Other
Parameter #9
Name
fixed frequency code (0-6)
ParameterKey
fix_freq
Description

fixed frequency code: 0=off, 1=0.25, 2=0.48, 3=1.00, 4=1.95, 5=4.00, 6=9.303 MHz

Support
SupportQuantity
Other
Parameter #10
Name
Year
ParameterKey
year
Description

Year of ionogram frame sync in UT

Support
SupportQuantity
Other
Parameter #11
Name
Day of Year
ParameterKey
doy
Description

Day of Year of ionogram frame sync in UT

Support
SupportQuantity
Other
Parameter #12
Name
Hour
ParameterKey
hr
Description

Hour of ionogram frame sync in UT

Support
SupportQuantity
Other
Parameter #13
Name
Minute
ParameterKey
min
Description

Minute of hour of ionogram frame sync in UT

Support
SupportQuantity
Other
Parameter #14
Name
Second
ParameterKey
sec
Description

Second of minute of ionogram frame sync in UT

Support
SupportQuantity
Other
Parameter #15
Name
Local Mean Time (hh,mm)
ParameterKey
LMT
Description

Local Mean Time (hh,mm) at time of ionogram frame sync

Structure
Size
2
Element
Name
LMT(hh)
Index
1
Units
hrs
Element
Name
LMT(mm)
Index
2
Units
min
Support
SupportQuantity
Other
Parameter #16
Name
geog coord (Lat,Long,Hgt)
ParameterKey
geo_coord
Description

geographic coordinates (Lat,Long,Hgt) at time of ionogram frame sync

Structure
Size
2
Element
Name
latitude
Index
1
Units
deg
Element
Name
longitude
Index
2
Units
deg
Element
Name
height
Index
3
Units
km
Support
SupportQuantity
Positional
Parameter #17
Name
Geomagnetic Local Time (hh,mm)
ParameterKey
GMLMT
Description

Geomagnetic Local Time (HHMM) at time of ionogram frame sync

Structure
Size
2
Element
Name
GMLMT(hh)
Index
1
Element
Name
GMLMT(mm)
Index
2
Support
SupportQuantity
Other
Parameter #18
Name
geom latitude
ParameterKey
GMLAT
Description

geomagnetic latitude at time of ionogram frame sync

Units
deg
Support
SupportQuantity
Positional
Parameter #19
Name
geom longitude
ParameterKey
GMLONG
Description

geomagnetic longitude at time of ionogram frame sync

Units
deg
Support
SupportQuantity
Positional
Parameter #20
Name
inv latitude
ParameterKey
INV_LAT
Description

invariant latitude at time of ionogram frame sync

Units
deg
Support
SupportQuantity
Other
Parameter #21
Name
magnetic inclination
ParameterKey
DIP
Description

Dip angle of mag field direction at time of ionogram frame sync

Units
deg
Support
SupportQuantity
Other
Parameter #22
Name
Solar Zenith Angle
ParameterKey
CHI
Description

Solar Zenith Angle at time of ionogram frame sync

Units
deg
Support
SupportQuantity
Other
Parameter #23
Name
L shell (McIlwain parameter)
ParameterKey
L
Description

L shell (McIlwain parameter) at time of ionogram frame sync

Support
SupportQuantity
Positional
Parameter #24
Name
spacecraft in/out sunlight
ParameterKey
sun
Description

spacecraft in(=1)/out(=2) sunlight at time of ionogram frame sync

Support
SupportQuantity
Other
Parameter #25
Name
Cyl. Electrost. Probe
ParameterKey
CEP
Description

CEP instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #26
Name
0.05-30 kHz VLF receiver
ParameterKey
VLF
Description

VLF receiver on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #27
Name
Spherical Electrostatic Analyzer
ParameterKey
SEA
Description

SEA instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #28
Name
Ion Mass Spectrometer 1
ParameterKey
IMS1
Description

IMS1 instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #29
Name
Ion Mass Spectrometer 2
ParameterKey
IMS2
Description

IMS2 instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #30
Name
Soft Particle Spectrometer
ParameterKey
SPS
Description

SPS instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #31
Name
Energetic Particle Detector
ParameterKey
EPD
Description

EPD instrument on(1)/off(0) status

Support
SupportQuantity
Other
Parameter #32
Name
start of swept-frequency portion
ParameterKey
swept_start
Description

scan line number of start of swept-frequency portion of the ionogram - seperates the fixed- and swept-frequency portions

Support
SupportQuantity
Other
Parameter #33
Name
times of ionogram frequency markers
ParameterKey
Time_mark
Description

msec after frame sync - time of frequency markers

Units
ms
Structure
Size
22
ValidMin
3000.0
ValidMax
30000.0
Support
SupportQuantity
Temporal
Parameter #34
Name
values of ionogram frequency markers
ParameterKey
freq_mark
Description

ionogram frequency markers

Units
MHz
Structure
Size
22
ValidMin
0.1
ValidMax
20.0
Support
SupportQuantity
Other
Parameter #35
Name
number of delay times per ionogram scan-line
ParameterKey
vh_num
Description

each sounder-pulse transmission is followed by a scan of the sounder-receiver video amplitude output values for each delay time monitored after the transmitted pulse; these scans are called scan lines. There are two types of ISIS-1 binary ionogram files, one designated as "full" and one as "average" The full file has 1340 delay times (one every 0.025ms). The average files are derived from the full files by averaging the amplitude values in 4 delay-time bins. Thus the average binary files contain 335 time-delay bins within each scan line. The cdf files were made from these average binary files.

Support
SupportQuantity
Other
Parameter #36
Name
number of ionogram scan-line frequencies
ParameterKey
f_num
Description

Ionogram files can be of different length. In some the swept-frequency portion covers the range 0.1 - 10 MHz, in others 0.1 - 20 MHz. Also, the proper start of each ionogram file, marked by a frame-sync pulse, was not always detected during the analog-to-digital (A/D) conversion. In such cases a frame sync was inserted to limit the file size. Thus the number of sounder-receiver video amplitude vs. delay time scan lines per ionogram can vary.

Support
SupportQuantity
Other
Parameter #37
Name
delay-time values
ParameterKey
delay_time
Description

delay-time values used in each scan line

Units
msec
Structure
Size
335
ValidMin
0.0
ValidMax
33.5
Support
SupportQuantity
Other
Parameter #38
Name
apparent-range values
ParameterKey
v_height
Description

apparent-range values used in each scan line

Units
km
Structure
Size
335
ValidMin
0.0
ValidMax
5025.0
Support
SupportQuantity
Other
Parameter #39
Name
Time
ParameterKey
Epoch
Description

Time

Units
ms
Support
SupportQuantity
Temporal
Parameter #40
Name
sounder receiver video amplitude
ParameterKey
ampl
Description

the sounder receiver linear video amplitude, from 0 to 255 telemetry units, in each apparent-range bin of each scan line covering the fixed- and swept-frequency regions. This range corresponds to a linear sounder-receiver video amplitude output range from zero to 4.5 V. This calibration is based on the video calibration pulse (of 3.0 V or 170 telemetry units) at the end of the line scan following each sounder pulse (the combined calibration pulses from all of the line scans produces a colored stripe at the bottom of the digital ionograms). In order to derive an input power level corresponding to the receiver video output it is necessary to know the sounder-receiver automatic-gain-control (AGC) voltage. This voltage was obtained from the pcm data and thus is only available if pcm data were available. The AGC voltage, which ranges from 0 to 5.12 volts, is obtained from a linear interpolation between the AGC trace displayed between 4005 km apparent range (26.7 ms delay time) as 5.12 V and 4395 km (29.3 ms delay time) as 0 volts. (On the full ionograms these numbers are 4001.250 km or 26.675 ms, and 4398.750 km or 29.325 ms.) On the average ionograms, which are available as either CDF or binary files from the SPDF or the NSSDC, the range resolution is 0.1 ms (corresponding to a virtual-range resolution of 15 km) there are 27 rows (26 intervals) covering the 0 to 5.12 V range; thus each row in virtual range above (decreasing delay time) the zero level (at 29.3 ms delay time) corresponds to an increase of 5.12/26 V of AGC with a quantization uncertainty of approximately plus or minus 0.1 V. Two rows have zero video-output amplitude values (on the average ionograms) in order that a clear AGC trace is visible on the ionograms. The row with the greatest virtual range corresponds to the actual AGC value. (On the full ionograms, which are only available as binary files from the NSSDC, the range resolution is 0.025 ms, corresponding to a virtual-range resolution of 3.75 km, and three rows have zero video-output amplitude values; the middle row corresponds to the actual AGC value.)

Structure
Size
335
ValidMin
0
ValidMax
255
Wave
WaveType
PlasmaWaves
Qualifier
Magnitude
Qualifier
Pseudo
WaveQuantity
Intensity
FrequencyRange
SpectralRange
RadioFrequency
Low
0.1
High
20
Units
MHz
Parameter #41
Name
scan-line frequency
ParameterKey
freq
Description

frequency of each scan line; in the swept-frequency portion of the ionogram they correspond to interpolated values between the frequency markers

Units
MHz
ValidMin
0.1
ValidMax
20.0
Support
SupportQuantity
Other
Parameter #42
Name
Electron Gyrofrequency
ParameterKey
FH
Description

Electron Gyrofrequency at time of ionogram frame sync

Units
MHz
Support
SupportQuantity
Other