2.2.1 spase://VWO/NumericalData/ISIS1/SFS/Ionogram.PT29S ISIS-1 Topside Sounder Ionograms ISIS-1 Topside Sounder Ionogram CDFs at NASA's CDAWeb 2012-02-24T17:50:32Z 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. 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. spase://SMWG/Person/J.H.Whitteker PrincipalInvestigator spase://SMWG/Person/Robert.F.Benson GeneralContact spase://SMWG/Person/Dieter.K.Bilitza GeneralContact ISIS/Alouette Topside Sounder Data Restoration Project http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html ISIS/Alouette page maintained by NASA GSFC with science and instrument descriptions, data access, software, and publication lists en NSSDC's Master Catalog http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1969-009A-01 Information about the Sweep Frequency Sounder experiment on ISIS-1. spase://VWO/NumericalData/ISIS1/SFS/ISIS1_Ionogram_CDF_PT29S spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Online Open CDAWeb FTP access to ISIS-1 Ionogram CDFs ftp://cdaweb.gsfc.nasa.gov/pub/data/isis/topside_sounder/ionogram_cdaweb/isis1 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 http://nssdc.gsfc.nasa.gov/space/isis/isis-table1-new.html A merged data set, independent of the ground stations, is in preparation. en CDAWeb web access portal to ISIS-1 Ionogram data http://cdaweb.gsfc.nasa.gov/pre_istp/ Repository of ISIS-1 data in CDF format at NASA CDAWeb, accessible via web interface. en CDF None 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. Calibrated spase://SMWG/Instrument/ISIS1/SFS Waves.Active Spectrum 1969-01-30T14:50:12Z 1983-12-30T15:19:33Z 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. PT24S RadioFrequency Earth.Magnetosphere Earth.Magnetosphere.Polar Earth.NearSurface.AuroralRegion Earth.NearSurface.PolarCap Earth.NearSurface.Ionosphere Earth.NearSurface.Ionosphere.Topside 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 satellite ID satellite sat.-ID: 1=AL1, 2=AL2, 3=ISIS1, 4=ISIS2 Other telemetry station code station_id two-digit telemetry station code Other transmitter power code power_code trans. power code: 1=Prim(400W) 2=Sec(400W) Other sounder/receiver code s/r_code sounder/receiver code: 0=off, 1=on Other pulse per second code pps_code pulse per second code: 0= 30 pps, 1= 60 pps Other DMODE code DMODE DMODE (transm. on/off for alternate frame pairs): 0=off, 1=on Other GMODE code GMODE GMODE (transmission of alternate frames of fixed-frequency ionograms and normal combined fixed- and swept-frequency ionograms): 0=off, 1=on" Other sounder mixed mode mixed_mode sounder mixed mode (transmission at a fixed-frequency while the sounder receiver sweeps over swept-frequency range): 0=off, 1=on Other fixed frequency code (0-6) fix_freq fixed frequency code: 0=off, 1=0.25, 2=0.48, 3=1.00, 4=1.95, 5=4.00, 6=9.303 MHz Other Year year Year of ionogram frame sync in UT Other Day of Year doy Day of Year of ionogram frame sync in UT Other Hour hr Hour of ionogram frame sync in UT Other Minute min Minute of hour of ionogram frame sync in UT Other Second sec Second of minute of ionogram frame sync in UT Other Local Mean Time (hh,mm) LMT Local Mean Time (hh,mm) at time of ionogram frame sync 2 LMT(hh) 1 hrs LMT(mm) 2 min Other geog coord (Lat,Long,Hgt) geo_coord geographic coordinates (Lat,Long,Hgt) at time of ionogram frame sync 2 latitude 1 deg longitude 2 deg height 3 km Positional Geomagnetic Local Time (hh,mm) GMLMT Geomagnetic Local Time (HHMM) at time of ionogram frame sync 2 GMLMT(hh) 1 GMLMT(mm) 2 Other geom latitude GMLAT geomagnetic latitude at time of ionogram frame sync deg Positional geom longitude GMLONG geomagnetic longitude at time of ionogram frame sync deg Positional inv latitude INV_LAT invariant latitude at time of ionogram frame sync deg Other magnetic inclination DIP Dip angle of mag field direction at time of ionogram frame sync deg Other Solar Zenith Angle CHI Solar Zenith Angle at time of ionogram frame sync deg Other L shell (McIlwain parameter) L L shell (McIlwain parameter) at time of ionogram frame sync Positional spacecraft in/out sunlight sun spacecraft in(=1)/out(=2) sunlight at time of ionogram frame sync Other Cyl. Electrost. Probe CEP CEP instrument on(1)/off(0) status Other 0.05-30 kHz VLF receiver VLF VLF receiver on(1)/off(0) status Other Spherical Electrostatic Analyzer SEA SEA instrument on(1)/off(0) status Other Ion Mass Spectrometer 1 IMS1 IMS1 instrument on(1)/off(0) status Other Ion Mass Spectrometer 2 IMS2 IMS2 instrument on(1)/off(0) status Other Soft Particle Spectrometer SPS SPS instrument on(1)/off(0) status Other Energetic Particle Detector EPD EPD instrument on(1)/off(0) status Other start of swept-frequency portion swept_start scan line number of start of swept-frequency portion of the ionogram - seperates the fixed- and swept-frequency portions Other times of ionogram frequency markers Time_mark msec after frame sync - time of frequency markers ms 22 3000.0 30000.0 Temporal values of ionogram frequency markers freq_mark ionogram frequency markers MHz 22 0.1 20.0 Other number of delay times per ionogram scan-line vh_num 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. Other number of ionogram scan-line frequencies f_num 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. Other delay-time values delay_time delay-time values used in each scan line msec 335 0.0 33.5 Other apparent-range values v_height apparent-range values used in each scan line km 335 0.0 5025.0 Other Time Epoch Time ms Temporal sounder receiver video amplitude ampl 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.) 335 0 255 PlasmaWaves Magnitude Pseudo Intensity RadioFrequency 0.1 20 MHz scan-line frequency freq frequency of each scan line; in the swept-frequency portion of the ionogram they correspond to interpolated values between the frequency markers MHz 0.1 20.0 Other Electron Gyrofrequency FH Electron Gyrofrequency at time of ionogram frame sync MHz Other