2.3.2
spase://NASA/NumericalData/ISIS1/SFS/AverageIonogram/Kwajalein/PT29S
ISIS-1 Topside Sounder Average Ionogram over Kwajalein, Marshall Islands: KWA, Latitude 9, Longitude 168
2021-04-27T15:38:11Z
This Ionogram was digitized from the original ISIS 1 Analog Telemetry Data on 7-Track Tape using the Facilities of the Data Evaluation Laboratory at NASA GSFC, Code 500. This Data Restoration Project is headed by Dr. R.F. Benson, NASA GSFC, Code 692. Ionograms were digitized at the Rate of 40,000 16-bit samples/s. This Sample Rate is higher than the Nyquist Frequency of 30 kHz. The Sample Frequency of 40 kHz provides a Measurement every 25 ms corresponding to an Apparent Range Interval of c*t/2, where c is the Speed of Light, or 3.747 km. Each Ionogram consists of a Fixed Frequency Portion and a Swept Frequency Portion. The Time Resolution is typically 29 s.
James H. Whitteker, Robert F. Benson, Dieter K. Bilitza. Please thank James H. Whitteker, Principal Investigator for the ISIS 1 Swept Frequency Sounder, SFS, Instrument and Robert F. Benson, Project Scientist for the Alouette/ISIS Data-Restoration
spase://SMWG/Person/James.H.Whitteker
PrincipalInvestigator
spase://SMWG/Person/Robert.F.Benson
GeneralContact
spase://SMWG/Person/Dieter.K.Bilitza
GeneralContact
spase://SMWG/Person/Leonard.N.Garcia
MetadataContact
spase://SMWG/Person/Robert.E.McGuire
MetadataContact
spase://SMWG/Person/Lee.Frost.Bargatze
MetadataContact
ISIS/Alouette Topside Sounder Data Restoration Project Site
https://spdf.gsfc.nasa.gov/isis/isis-status.html
ISIS/Alouette Page maintained by NASA GSFC with Science and Instrument Descriptions, Data Access, Software, and Publication Lists
NSSDC Master Catalog
https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1969-009A
Information about the Swept Frequency Sounder, SFS, Experiment on Alouette 2
spase://VSPO/NumericalData/ISIS1/SFS/AverageIonogram/Kwajalein/PT29S
spase://SMWG/Repository/NASA/GSFC/SPDF
Online
Open
FTPS from SPDF (not with most browsers)
ftps://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_cdf/isis1/KWA_09N_168E/
Access to Data in CDF Format via ftp from SPDF
HTTPS from SPDF
https://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_cdf/isis1/KWA_09N_168E/
Access to Data in CDF Format via http from SPDF
CDAWeb
https://cdaweb.gsfc.nasa.gov/index.html/
I1_AV_KWA
Access to ASCII, CDF, and plots via NASA/GSFC CDAWeb
CDF
None
James H. Whitteker, Robert F. Benson, Dieter K. Bilitza. Please thank James H. Whitteker, Principal Investigator for the ISIS 1 Swept Frequency Sounder, SFS, Instrument and Robert F. Benson, Project Scientist for the Alouette/ISIS Data-Restoration. Please acknowledge the data providers and CDAWeb when using these data.
spase://SMWG/Repository/NASA/GSFC/SPDF
Online
Open
CDAWeb HAPI Server
https://cdaweb.gsfc.nasa.gov/hapi
I1_AV_KWA
Web Service to this product using the HAPI interface.
CSV
James H. Whitteker, Robert F. Benson, Dieter K. Bilitza. Please thank James H. Whitteker, Principal Investigator for the ISIS 1 Swept Frequency Sounder, SFS, Instrument and Robert F. Benson, Project Scientist for the Alouette/ISIS Data-Restoration. Please acknowledge the data providers and CDAWeb when using these data.
Calibrated
spase://SMWG/Instrument/ISIS1/SFS
Spectrum
Waves.Active
1978-01-03T04:13:25
1978-12-30T21:34:08
The Cadence is 31 s between Ionograms. The Alouette 2 Ionograms have the slowest Sweep Rate of any of the Alouette/ISIS Topside Sounders sweeping from 0.12 to 14.5 MHz in about 28 s with a Frequency Sweep Rate of 0.13 MHz/s below 2.0 MHz, providing the highest Frequency Resolution of any of the ISIS Program Sounders. The Alouette 2 Frequency Sweep Rate above 2 MHz was 1 MHz/s. Alouette 2 did not have a Fixed Frequency Operation.
PT29S
RadioFrequency
Earth.Magnetosphere
Earth.Magnetosphere.Polar
Earth.NearSurface
Earth.NearSurface.AuroralRegion
Earth.NearSurface.EquatorialRegion
Earth.NearSurface.Ionosphere
Earth.NearSurface.PolarCap
Ionogram
Topside Sounder
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
Auroral Kilometric Radiation, AKR
Solar Type III Bursts
Upper Hybrid Noise Band
Satellite ID
satellite
Satellite ID: 1=Alouette 1, 2=Alouette 2, 3=ISIS 1, 4=ISIS 2
PT29S
s/c_ID
I1
1
4
1
4
-2147483648
Other
Telemetry Station Code
station_id
Two-Digit Telemetry Station Code
PT29S
station
I2
1
99
1
99
-2147483648
Other
Transmitter Power Code
power_code
Transmitter Power Code: 1=Primary, 400 W, 2=Secondary, 400 W
PT29S
T_power
I1
1
2
1
2
-2147483648
InstrumentMode
Sounder-Receiver Code
s/r_code
Sounder-Receiver Code: 0=Off, 1=On
PT29S
s/r_code
I1
0
1
0
1
-2147483648
InstrumentMode
Pulse per Second Code
pps_code
Pulse per Second Code: 0=30 Pulses/s, 1=60 Pulses/s
PT29S
pps_code
I1
0
1
0
1
-2147483648
InstrumentMode
DMODE Code
DMODE
DMODE, Transmission On/Off for Alternate Frame Pairs: 0=Off, 1=On
PT29S
DMODE
I1
0
1
0
1
-2147483648
InstrumentMode
GMODE Code
GMODE
GMODE, Transmission of Alternate Frames of Fixed Frequency Ionograms and Normal Combined Fixed Frequency and Swept Frequency Ionograms: 0=Off, 1=On
PT29S
GMODE
I1
0
1
0
1
-2147483648
InstrumentMode
Sounder Mixed Mode
mixed_mode
Sounder Mixed Mode, Transmission at a Fixed Frequency while the Sounder-Receiver sweeps over the Swept Frequency Range: 0=Off, 1=On
PT29S
s_m_mode
I1
0
1
0
1
-2147483648
InstrumentMode
Fixed Frequency Code
fix_freq
Fixed Frequency Code: 0=Off, 1=0.25 MHz, 2=0.48 MHz, 3=1.00 MHz, 4=1.95 MHz, 5=4.00 MHz, 6=9.303 MHz
PT29S
f_code
I1
0
6
0
6
-2147483648
InstrumentMode
Year
year
Year of Ionogram Frame Sync
PT29S
year
I2
62
83
62
84
-2147483648
Temporal
Day of Year
doy
Day of Year of Ionogram Frame Sync
PT29S
DOY
I3
1
366
1
366
-2147483648
Temporal
Hour of Day
hr
Hour of Day of Ionogram Frame Sync, UT
PT29S
Hour
I2
0
24
0
24
-2147483648
Temporal
Minute of Hour
min
Minute of Hour of Ionogram Frame Sync, UT
PT29S
min
I2
0
60
0
60
-2147483648
Temporal
Second of Minute
sec
Second of Minute of Ionogram Frame Sync, UT
PT29S
second
F7.4
0.0
60.0
0.0
60.0
-1.0e+31
Temporal
Local Mean Time
LMT
Local Mean Time, LMT, at the Time of Ionogram Frame Sync, Format: HH,MM
PT29S
I2
2
Element 1
1
h
60>s
0
24
LMT(hh)
0
24
Element 2
2
min
3600>s
0
60
LMT(mm)
0
60
-2147483648
DirectionAngle.AzimuthAngle
Positional
Geographic Coordinates
geo_coord
Geographic Coordinates, GEO, Latitude, Longitude, Height, at the Time of Ionogram Frame Sync
PT29S
Spherical
GEO
F7.2
3
Element 1
1
°
0.0174532925>rad
-90.0
90.0
latitude
-90.0
90.0
Element 2
2
°
0.0174532925>rad
0.0
360.0
longitude
0.0
360.0
Element 3
3
km
1e3>m
0.0
10000.0
height
0.0
10000.0
-1.0e+31
Vector
Positional
Geomagnetic Local Time
GMLMT
Geomagnetic Local Time, GMLMT, Format: HH,MM, at the Time of Ionogram Frame Sync
PT29S
Spherical
LGM
I2
2
Element 1
1
h
60>s
0
24
GMLMT(hh)
0
24
Element 2
2
min
3600>s
0
60
GMLMT(mm)
0
60
-2147483648
DirectionAngle.AzimuthAngle
Positional
Geomagnetic Latitude
GMLAT
Geomagnetic Latitude, MAG, at the Time of Ionogram Frame Sync
PT29S
°
0.0174532925>rad
Spherical
MAG
geom_lat
F7.2
-90.0
90.0
-90.0
90.0
-1.0e+31
DirectionAngle.ElevationAngle
Positional
Geomagnetic Longitude
GMLONG
Geomagnetic Longitude, MAG, at the Time of Ionogram Frame Sync
PT29S
°
0.0174532925>rad
Spherical
MAG
geom_long
F7.2
-180.0
180.0
-180.0
360.0
-1.0e+31
DirectionAngle.AzimuthAngle
Positional
Invariant Latitude
INV_LAT
Invariant Latitude, at the Time of Ionogram Frame Sync
PT29S
°
0.0174532925>rad
inv_lat
F7.2
-90.0
90.0
-90.0
90.0
-1.0e+31
DirectionAngle.ElevationAngle
Positional
Magnetic Inclination
DIP
Magnetic Inclination, Dip Angle of Magnetic Field Direction, at the Time of Ionogram Frame Sync
PT29S
°
0.0174532925>rad
Spherical
LGM
DIP
I3
-90
90
-90
90
-2147483648
DirectionAngle.ElevationAngle
Magnetic
Solar Zenith Angle
CHI
Solar Zenith Angle, SZA, at the Time of Ionogram Frame Sync
PT29S
°
0.0174532925>rad
CHI
F7.2
0
180
0
180
-2147483648
DirectionAngle.PolarAngle
Positional
L Shell
L
L Shell, McIlwain Parameter, at the Time of Ionogram Frame Sync
PT29S
L
F7.2
0.0
180.0
0.0
180.0
-1.0e+31
Other
Spacecraft Sunlight
sun
Spacecraft Sunlight: 0=Out, 1=In, at the Time of Ionogram Frame Sync
PT29S
sun
I1
1
2
1
2
-2147483648
Other
CEP, Instrument Status
CEP
Cylindrical Electrostatic Probe, CEP, Instrument Status: 0=Off, 1=On
PT29S
CEP
I1
0
1
0
1
-2147483648
InstrumentMode
VLF, Instrument Status
VLF
Very Low Frequency, VLF, 0.05 to 30 kHz Receiver, Instrument Status: 0=Off, 1=On
PT29S
VLF
I1
0
1
0
1
-2147483648
InstrumentMode
SEA, Instrument Status
SEA
Spherical Electrostatic Analyzer, SEA, Instrument Status: 0=Off, 1=On
PT29S
SEA
I1
0
1
0
1
-2147483648
InstrumentMode
IMS1, Instrument Status
IMS1
Ion Mass Spectrometer 1, IMS1, Instrument Status: 0=Off, 1=On
PT29S
IMS-1
I1
0
1
0
1
-2147483648
InstrumentMode
IMS2, Instrument Status
IMS2
Ion Mass Spectrometer 2, IMS1, Instrument Status: 0=Off, 1=On
PT29S
IMS-2
I1
0
1
0
1
-2147483648
InstrumentMode
SPS, Instrument Status
SPS
Soft Particle Spectrometer, SPS, Instrument Status: 0=Off, 1=On
PT29S
SPS
I1
0
1
0
1
-2147483648
InstrumentMode
EPD, Instrument Status
EPD
Energetic Particle Detector, EPD, Instrument Status: 0=Off, 1=On
PT29S
EPD
I1
0
1
0
1
-2147483648
InstrumentMode
Start of Swept Frequency Portion
swept_start
Scan Line Number of the Start of Swept Frequency Portion of the Ionogram, this seperates the Fixed Frequency and Swept Frequency Portions of the Ionogram
seperates the fixed and swept portions
PT29S
swept_start
I5
0
10000
0
10000
-2147483648
Other
Times of Ionogram Frequency Markers
Time_mark
Times of Ionogram Frequency Markers, Milliseconds after Frame Sync
time of frequency markers This parameter exhibits an increasing monotonic progression.
PT29S
ms
1e-3>s
F10.3
3000.0
30000.0
22
Element 1
1
Element 2
2
Element 3
3
Element 4
4
Element 5
5
Element 6
6
Element 7
7
Element 8
8
Element 9
9
Element 10
10
Element 11
11
Element 12
12
Element 13
13
Element 14
14
Element 15
15
Element 16
16
Element 17
17
Element 18
18
Element 19
19
Element 20
20
Element 21
21
Element 22
22
3000.0
30000.0
-1.0e+31
Temporal
Values of Ionogram Frequency Markers
freq_mark
Ionogram Frequency Marker Valuess
PT29S
MHz
1e6>Hz
E11.2
0.1
20.0
22
Element 1
1
Element 2
2
Element 3
3
Element 4
4
Element 5
5
Element 6
6
Element 7
7
Element 8
8
Element 9
9
Element 10
10
Element 11
11
Element 12
12
Element 13
13
Element 14
14
Element 15
15
Element 16
16
Element 17
17
Element 18
18
Element 19
19
Element 20
20
Element 21
21
Element 22
22
0.0
25.0
-1.0e+31
Other
Number of Delay Times per Ionogram Scan Line
vh_num
Number of Delay Times per Ionogram Scan Line. 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 the other designated as Average. The Full File has 1340 Delay Times, one every 0.025 ms. The Average Files are derived from the Full Files by averaging the Amplitude Values in four 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.
PT29S
N_vh
I3
0
335
0
350
-2147483648
Other
Number of Ionogram Scan Line Frequencies
f_num
Number of Ionogram Scan Line Frequencie Steps. Ionogram Files can be of different Lengths. In some the Swept Frequency Portion covers the Range from 0.1 Mhz to 10 MHz, in others from 0.1 Mhz to 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 versus Delay Time Scan Lines per Ionogram can vary.
PT29S
N_f
I6
0
4000
0
4000
-2147483648
Other
Delay Time Values
delay_time
Delay Time Values used in each Scan Line
PT29S
ms
1e-3>s
F9.2
LinearScale
335
-1.0e+31
Temporal
Apparent Range Values
v_height
Virtual Height Values corresponding to Delay Times used in each Scan Line
PT29S
km
1e3>m
F9.2
LinearScale
335
-1.0e+31
Magnitude
Other
Epoch Time
Epoch
Epoch Time
This parameter exhibits an increasing monotonic progression.
PT29S
ms
1e-3>s
Epoch
6.2135661819904e+13
6.3113882619904e+13
01-Jan-1969 00:00:00.000
01-Jan-2000 00:00:00.000
-1.0e+31
Temporal
Sounder Amplitude
Time series defined by using: EPOCH
ampl
Sounder Amplitude at 335 Virtual Heights for Fixed Frequency and Swept Frequency, Ionogram. The Sounder-Receiver Linear Video Amplitude, from 0 to 255 Telemetry Units, in each Apparent Range Bin of each Scan Line covering the Fixed Frequency and Swept Frequency Regions. This Range corresponds to a Linear Sounder-Receiver Video Amplitude Output Range from 0 V 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 Pulse Code Modulation, PCM, Data and thus is only available if PCM Data were available. The AGC Voltage, which ranges from 0 V to 5.12 V, is obtained from a Linear Interpolation between the AGC Trace displayed between the 4005 km Apparent Range, at 26.7 ms Delay Time, as 5.12 V and the 4395 km, at 29.3 ms Delay Time, as 0 V. 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 an thus 26 Intervals covering the 0 V to 5.12 V Range; thus each Row in Virtual Range above, i.e. 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.
PT29S
I3
335
-128
PlasmaWaves
Magnitude
Pseudo
Intensity
Interpolated Frequencies
Time series defined by using: EPOCH
freq
Interpolated Fixed and Swept Frequencies for each Scan Line, in the Swept Frequency Portion of the Ionogram they correspond to interpolated Values between the Frequency Markers
This variable could be used as x-axis on amplitude spectrograms if fixed part is subtracted.
PT29S
MHz
1e6>Hz
TimeSeries
Frequency
E11.2
0.1
25.0
0.1
25.0
-1.0e+31
PlasmaWaves
Scalar
Frequency
Height
Time series defined by using: EPOCH
height
Satellite Altitude
Virtual variable. This parameter is virtual. It is calculated by calling the function HEIGHT_ISIS with the following input parameters: geo_coord.
PT29S
km
1e3>m
TimeSeries
Satellite Altitude
F6.1
0.0
4000.0
0.0
4000.0
-1.0e+31
Magnitude
Positional
Electron Local Gyrofrequency
Time series defined by using: EPOCH
FH
Electron Local Gyrofrequency, at the Time of Ionogram Frame Sync
PT29S
MHz
1e6>Hz
TimeSeries
Electron Gyrofrequency
F7.3
0.0
100.0
0.0
100.0
-1.0e+31
Electron
Gyrofrequency