2.3.1 spase://VSPO/NumericalData/ISIS1/SFS/AverageIonogramNew/Fairbanks/PT29S ISIS-1 Topside Sounder Ionogram over Fairbanks, AK, USA, Version 2, Swept-Frequency Sounder (SFS) (Latitude 65°, Longitude 212°), 29 s Data 2020-04-21T12:34:56.789Z 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. Please acknowledge James H. Whitteker, Robert F. Benson, and 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 project. 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.M.Candey 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 ISIS 1 spase://SMWG/Repository/NASA/GSFC/SPDF Online Open FTP access to CDF Files at SPDF ftps://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_new_i1_cdf/isis1/ula_65n_212e/ Access to Data in CDF Format via ftp from SPDF HTTP access to CDF Files at SPDF https://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_new_i1_cdf/isis1/ula_65n_212e/ Access to Data in CDF Format via http from SPDF CDAWeb https://cdaweb.sci.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=I1_AV2_ULA&index=sp_phys I1_AV2_ULA Access to ASCII, CDF, and Plots via NASA/GSFC CDAWeb CDF None Please acknowledge James H. Whitteker, Robert F. Benson, and 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 project. Please acknowledge the data providers and CDAWeb when using these data. Calibrated spase://SMWG/Instrument/ISIS1/SFS Spectrum Waves.Active Spectrum Waves.Active 1975-01-04T18:15:50 1979-09-14T12:06:02 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, GEO, Coordinates, 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 Height Time series defined by using: EPOCH height Satellite Altitude 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 gyrof F7.3 0.0 100.0 0.0 100.0 -1.0e+31 Electron Gyrofrequency 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 T_mark F10.3 3000.0 30000.0 22 3000.0 30000.0 -1.0e+31 Temporal Values of Ionogram Frequency Markers freq_mark Ionogram Frequency Marker Valuess PT29S MHz 1e6>Hz freq E11.2 0.1 20.0 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 Delay time 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 V_height 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 31-Dec-9999 23:59:59.999 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 Relative Amplitude 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