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1) Akebono PWS NPW Data maxmize
Resource ID:spase://VWO/NumericalData/Akebono/PWS/E.NPW.PT2S
Start:1989-02-24 13:32:00 Observatory:Akebono Cadence:2 seconds
Stop:2016-09-14 08:00:15 Instrument:Plasma Wave Observation and Sounder Experiments (PWS) Resource:NumericalData
The Plasma Wave Observation and Sounder Experiment (PWS) observes both natural (NPW) and stimulated (SPW) plasma waves. The frequency range of the NPW system is 20 kHz to 5.12 MHz. These CDF data consist of Electric Field intensities measured by the PWS Recevier 1 (RX1) and Receiver 2 (RX2) units.

2) Alouette-2 Topside Sounder Ionogram Data maxmize
Resource ID:spase://VWO/NumericalData/Alouette2/SFS/PT31S
Start:1965-11-29 13:42:37 Observatory:Alouette 2 Cadence:31 seconds
Stop:1968-01-01 04:11:45 Instrument:Alouette 2 Sweep-Frequency Sounder Resource:NumericalData
These ionograms were digitized from the original Alouette 2 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. The ionograms consist of swept-frequency operation (there is no fixed-frequency operation as in ISIS-1 and ISIS-2). The time resolution between ionograms is typically 31 seconds.

3) Cassini RPWS Key Parameter 60S maxmize
Resource ID:spase://VWO/NumericalData/Cassini/RPWS/KP_PT60S
Start:1997-10-25 00:00:00 Observatory:Cassini Cadence:60 seconds
Stop:2015-11-19 08:00:15 Instrument:Cassini RPWS Resource:NumericalData
The Cassini Radio and Plasma Wave Science (RPWS) calibrated summary key parameter data set includes reduced temporal and spectral resolution spectral information calibrated in units of spectral density for the entire Cassini mission. This data set includes calibrated values binned and averaged within 1 minute by 0.1 decade spectral channels for all times during the mission including the two Venus flybys, the Earth flyby, the Jupiter flyby, interplanetary cruise, and the entire Saturn tour. Data for this data set are acquired by the RPWS Low Frequency Receiver (LFR), Medium Frequency Receiver (MFR), and High Frequency Receiver (HFR). Data are presented in a set of fixed-record-length tables. This data set is intended to provide numerical summary data which can be used in conjunction with other Cassini fields and particles key parameter data sets to establish trends, select events, or simply as a browse data set for the Cassini RPWS archive. This data set should be among the first used by a user of any of the RPWS archive as it will lead one to information required to search for more detailed or highly specialized products.

4) Cassini RPWS Low Rate Full Resolution maxmize
Resource ID:spase://VWO/NumericalData/Cassini/RPWS/LRFULL_PT32S
Start:1997-10-25 00:00:00 Observatory:Cassini Cadence:32 seconds
Stop:2015-11-19 08:00:15 Instrument:Cassini RPWS Resource:NumericalData
The Cassini Radio and Plasma Wave Science (RPWS) Low Rate Full Resolution Calibrated (RPWS_LOW_RATE_FULL) is a data set including all spectral density measurements acquired by the RPWS in units of electric or magnetic field spectral density. This data set includes calibrated values for each frequency channel for each sensor for all times during the mission including the two Venus flybys, the Earth flyby, the Jupiter flyby, interplanetary cruise, and the entire Saturn tour. Data for this data set are acquired from the RPWS Low Frequency Receiver (LFR), Medium Frequency Receiver (MFR), Medium Frequency Digital Receiver (MFDR) (which can be used to replace MFR band 2 data) and High Frequency Receiver (HFR). Data are presented in a set of tables organized so as to have fixed-length records for ease in data handling. This data set is intended to be the most comprehensive and complete data set included in the Cassini RPWS archive. A browse data set is included with these data which provides for a graphical search of the data using a series of thumbnail and full-sized spectrograms which lead the user to the particular data file(s) of interest. This data set should be among the first used by a user of any of the RPWS archive as it will lead one to information required to search for more detailed or highly specialized products.

5) Cluster 1 WHISPER Active Electric Power Spectral Density maxmize
Resource ID:spase://VWO/NumericalData/Cluster-Rumba/WHISPER/PT52S
Start:2000-08-16 12:39:00 Observatory:Cluster FM5 (Rumba) Cadence:52 seconds
Stop:2016-09-14 08:00:14 Instrument:Waves of HF and Sounder for Probing Electron Density by Relaxation (WHISPER) Resource:NumericalData
The Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation (WHISPER) performs the measurement of the electron density on the four satellites of the Cluster project. The two main purposes of the WHISPER experiment are to record the natural waves and to make a diagnostic of the electron density using the sounding technique. The various working modes and the fourier transforms calculated on board provide a good frequency resolution obtained in the bandwidth 2-83 kHz. Onboard data compression by the Digital Wave Processing (DWP) intrument allows a good dynamic and level resolution of the electric signal amplitude.

6) Cluster 2 WHISPER Active Electric Power Spectral Density maxmize
Resource ID:spase://VWO/NumericalData/Cluster-Salsa/WHISPER/PT52S
Start:2000-08-16 12:39:00 Observatory:Cluster FM6 (Salsa) Cadence:52 seconds
Stop:2016-09-14 08:00:15 Instrument:Waves of HF and Sounder for Probing Electron Density by Relaxation (WHISPER) Resource:NumericalData
The Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation (WHISPER) performs the measurement of the electron density on the four satellites of the Cluster project. The two main purposes of the WHISPER experiment are to record the natural waves and to make a diagnostic of the electron density using the sounding technique. The various working modes and the fourier transforms calculated on board provide a good frequency resolution obtained in the bandwidth 2-83 kHz. Onboard data compression by the Digital Wave Processing (DWP) intrument allows a good dynamic and level resolution of the electric signal amplitude.

7) Cluster 3 WHISPER Active Electric Power Spectral Density maxmize
Resource ID:spase://VWO/NumericalData/Cluster-Samba/WHISPER/PT52S
Start:2000-08-16 12:39:00 Observatory:Cluster FM7 (Samba) Cadence:52 seconds
Stop:2016-09-14 08:00:15 Instrument:Waves of HF and Sounder for Probing Electron Density by Relaxation (WHISPER) Resource:NumericalData
The Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation (WHISPER) performs the measurement of the electron density on the four satellites of the Cluster project. The two main purposes of the WHISPER experiment are to record the natural waves and to make a diagnostic of the electron density using the sounding technique. The various working modes and the fourier transforms calculated on board provide a good frequency resolution obtained in the bandwidth 2-83 kHz. Onboard data compression by the Digital Wave Processing (DWP) intrument allows a good dynamic and level resolution of the electric signal amplitude.

8) Cluster 4 WHISPER Active Electric Power Spectral Density maxmize
Resource ID:spase://VWO/NumericalData/Cluster-Tango/WHISPER/PT52S
Start:2000-08-16 12:39:00 Observatory:Cluster FM8 (Tango) Cadence:52 seconds
Stop:2016-09-14 08:00:15 Instrument:Waves of HF and Sounder for Probing Electron Density by Relaxation (WHISPER) Resource:NumericalData
The Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation (WHISPER) performs the measurement of the electron density on the four satellites of the Cluster project. The two main purposes of the WHISPER experiment are to record the natural waves and to make a diagnostic of the electron density using the sounding technique. The various working modes and the fourier transforms calculated on board provide a good frequency resolution obtained in the bandwidth 2-83 kHz. Onboard data compression by the Digital Wave Processing (DWP) intrument allows a good dynamic and level resolution of the electric signal amplitude.

9) GIRO Ionogram-Derived Ionospheric Characteristics maxmize
Resource ID:spase://VWO/NumericalData/GIRO/CHARS.PT15M
Start:1987-01-01 00:00:05 Observatory:GIRO Group Cadence:15 minutes
Stop:2016-09-14 07:55:15 Instrument:GIRO Ionospheric Sounder Resource:NumericalData
Standard ionogram-derived characteristics obtained by Global Ionospheric Radio Observatory (GIRO) operated by University of Massachusetts Lowell. The list of standard URSI characteristics that can be derived from ionograms can be found in the SAO.XML Data Model Specification for standard ionosonde data exchange, Appendix C, http://ulcar.uml.edu/SAOXML/. In order to request the characteristics values from GIRO, it is necessary to call DIDBGetValues() servlet at GIRO server using standard HTTP call that returns a text document. The values in the document are calculated using automatic or manual interpretation of ionogram images. Each measurement is accompanied by a confidence score value (from 0 to 100, 100 is best autoscaled confidence or data obtained manually) and a set of two QD letters (qualitative and descriptive letters per URSI ionogram interpretation manual). When QD letters are set to //, reported value is obtained automatically, all other combinations of the letters correspond to manual scaling.

10) GIRO Ionogram Plots maxmize
Resource ID:spase://VWO/DisplayData/GIRO/GRM.PT15M
Start:1987-01-01 00:00:05 Observatory:GIRO Group Cadence:15 minutes
Stop:2016-09-14 07:55:14 Instrument:GIRO Ionospheric Sounder Resource:DisplayData
Collection of GIRO ionogram images at University of Massachusetts Lowell, covering selected ionosonde stations and periods of time from 1987-01-01 to current time, including 42 real-time data feeds. Total number of GIRO locations represented is 68 as of February 14, 2012. Access to images is arranged via a webpage containing a browsable data availability table. GIRO ionograms are visualized by plotting images in which received signal strength (color scale) is a function of echo delay (virtual range in vertical scale) and ionosonde frequency (horizontal scale) of the transmitted pulses. Echoes that can be used to derive remote vertical electron-density profiles, appear as discrete traces on ionograms. The ionogram traces are extracted (scaled) using image recognition software to obtain ionogram-derived characteristics of ionospheric plasma. Extracted traces and a table of major ionospheric characteristics are superimposed on the ionogram image

11) GIRO Doppler Skymap Plots maxmize
Resource ID:spase://VWO/DisplayData/GIRO/SKYMAP.PT15M
Start:1987-01-01 00:00:05 Observatory:GIRO Group Cadence:15 minutes
Stop:2016-09-14 07:55:14 Instrument:GIRO Ionospheric Sounder Resource:DisplayData
Collection of GIRO Doppler skymap images at University of Massachusetts Lowell, covering selected ionosonde stations and periods of time from 1993-07-20 to current time, including 28 real-time feeds. Total number of GIRO locations represented is 50 as of February 14, 2012. Access to images is arranged via a webpage containing a browsable data availability table. GIRO skymaps are visualized by plotting received echoes in the polar coordinate system using echo zenith and azimuth information. Color scale is used to represent Doppler Velocity of the signal reflection area in the ionosphere. Additionally, observed echoes on the skymap are used to derived zenith and azimuth of the ionospheric tilt, as well as vertical and horizontal components of the bulk ionospheric motion across the sounder location.

12) RPI Plasmagram Full Resolution Binary Data maxmize
Resource ID:spase://VWO/NumericalData/IMAGE/RPI/PGM.CCSDS.PT5M
Start:2000-04-21 20:24:42 Observatory:IMAGE Cadence:5 minutes
Stop:2005-12-11 02:43:10 Instrument:Radio Plasma Imager (RPI) Resource:NumericalData
RPI plasmagram full resolution data (received signal strength in the frequency-range frame), uncalibrated. Presented as instrument packets wrapped in the standard CCSDS headers. Description of the RPI instrument-level data model can be found at http://ulcar.uml.edu/RPI/RPITelemetryDataFormat_V2.8.pdf. Data are viewed/calibrated/edited by BinBrowser software, see http://ulcar.uml.edu/rpi.html for download and users' guide. RPI plasmagrams are visualized by plotting images in which received signal strength (color scale) is a function of echo delay (range in vertical scale) and radio-sounder frequency (horizontal scale) of the radar pulses. Echoes from important magnetospheric structures, such as the magnetopause and the plasmapause, appear as traces on plasmagrams. Plasmagram traces are intermixed with vertical signatures corresponding to the locally excited plasma resonances and various natural emissions propagating in space.

13) IMAGE RPI Plasmagram Plots maxmize
Resource ID:spase://VWO/DisplayData/IMAGE/RPI/PGM.PT5M
Start:2000-04-21 20:24:42 Observatory:IMAGE Cadence:5 minutes
Stop:2005-12-18 07:50:00 Instrument:Radio Plasma Imager (RPI) Resource:DisplayData
Collection of RPI Plasmagram images at University of Massachusetts Lowell, covering complete mission period from 2000-04-21 to 2005-12-18. Access to images is arranged via a webpage containing a query form with the time period of interest and options for search of expert-annotated plasmagrams. The query returns a list of qualifying plasmagrams with URLs pointing to images. RPI plasmagrams are visualized by plotting images in which received signal strength (color scale) is a function of echo delay (range in vertical scale) and radio-sounder frequency (horizontal scale) of the sounder pulses. Echoes that can be used to derive remote, long-range, magnetospheric electron-density profiles, appear as discrete traces on plasmagrams. These plasmagram traces are intermixed with vertical signatures with greater intensity at shorter ranges, corresponding to locally excited plasma resonances, and other vertical signatures that cover the entire listening period, i.e., the entire virtual-range scale, corresponding to various natural and/or man-made emissions propagating in space and/or local interference.

14) IMAGE RPI Monthly Electron Density Values maxmize
Resource ID:spase://VSPO/NumericalData/IMAGE/RPI/PT1M
Start:2001-01-01 00:00:00 Observatory:IMAGE Cadence:1 minute
Stop:2005-12-01 00:00:00 Instrument:Radio Plasma Imager (RPI) Resource:NumericalData
The electron density values listed in this file are derived from the IMAGE Radio Plasma Imager (B.W. Reinisch, PI) data using an automatic fitting program written by Phillip Webb with manual correction. The electron number densities were produced using an automated procedure (with manual correction when necessary) which attempted to self-consistently fit an enhancement in the IMAGE RPI Dynamic Spectra to either 1) the Upper Hybrid Resonance band, 2) the Z-mode or 3) the continuum edge. The automatic algorithm works by rules determined by comparison of the active and passive RPI data [Benson et al., GRL, vol. 31, L20803, doi:10.1029/2004GL020847, 2004]. The manual data points are not from frequencies chosen freely by a human. Rather the human specifies that the computer should search for a peak or continuum edge in a certain frequency region. Thus even the manual points are determined, in part, by the automatic algorithms. Of course that does not guarantee that the data points are right, but it does eliminate some human bias.

15) IMAGE RPI Plasmagram/Echogram Key Parameters maxmize
Resource ID:spase://VSPO/NumericalData/IMAGE/RPI/PT24H
Start:2000-03-26 00:00:00 Observatory:IMAGE Cadence:24 hours
Stop:2005-12-18 00:00:00 Instrument:Radio Plasma Imager (RPI) Resource:NumericalData
This set of daily plasmagrams/echograms comes from the IMAGE Radio Plasma Imager that studies the Earth's magnetophere in the 3 kHz to 3 MHz frequency range. RPI plasmagrams are visualized by plotting images in which received signal strength (color scale) is a function of echo delay (range in vertical scale) and radio-sounder frequency (horizontal scale) of the sounder pulses. Echoes that can be used to derive remote, long-range, magnetospheric electron-density profiles, appear as discrete traces on plasmagrams. These plasmagram traces are intermixed with vertical signatures with greater intensity at shorter ranges, corresponding to locally excited plasma resonances, and other vertical signatures that cover the entire listening period, i.e., the entire virtual-range scale, corresponding to various natural and/or man-made emissions propagating in space and/or local interference.

16) ISIS 1 Swept-/Fixed-Averaged Ionograms maxmize
Resource ID:spase://VSPO/NumericalData/ISIS1/SFS/AveragedIonongrams
Start:1969-01-30 14:50:12 Observatory:ISIS 1 Cadence:
Stop:1983-12-30 15:19:33 Instrument:ISIS1 Swept-Frequency Sounder Resource:NumericalData
This data set consists of ISIS 1 (International Satellites for Ionospheric Studies)ionograms that have been obtained through a data restoration project. The ISIS ionograms, consisting of a fixed-frequency and a swept-frequency part, were digitized from the original ISIS telemetry tapes. The digitized sounder data consisting of 8-bit receiver-amplitude values collected at a 40 kHz rate contain the time and the frequency associated with each sounder pulse. The frequency of each sounder pulse is determined from a 3rd degree interpolation between the times of the frequency markers as identified in the sounder video during the A/D operation. Included in this data set are the average-resolution ionograms (averages of each 4 successive 40 kHz 8-bit values) in CDF format. Software to read and display the individual CDF files is available at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/software/ These CDF files were produced at NSSDC from the original PI-provided ionogram data. Other ionogram data sets available at NSSDC include the full resolution ionograms and average ionograms both in the PI-provided (OS2) binary format, ASCII header files with pass-specific information and the PCM data which contain header, time, AGC, frequency-marker information and telemetry-level data from all other ISIS instruments. The binary average ionograms and the ASCII header files are available online at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/topside_sounder/ ISIS 1 and 2 data are available to the extent permitted by telemetry scheduling and the location of telemetry stations. A list of stations can be found at http://nssdc.gsfc.nasa.gov/space/isis/isis-table1-new.html and their location on a worldmap is shown in http://nssdc.gsfc.nasa.gov/space/isis/isis_station_lar.GIF (

17) ISIS-1 Topside Sounder Ionograms maxmize
Resource ID:spase://VWO/NumericalData/ISIS1/SFS/Ionogram.PT29S
Start:1969-01-30 14:50:12 Observatory:ISIS 1 Cadence:24 seconds
Stop:1983-12-30 15:19:33 Instrument:ISIS1 Swept-Frequency Sounder Resource:NumericalData
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.

18) ISIS 2 Swept-/Fixed-Averaged Ionograms maxmize
Resource ID:spase://VSPO/NumericalData/ISIS2/SFS/AveragedIonongrams
Start:1969-01-30 14:50:12 Observatory:ISIS 2 Cadence:
Stop:1984-01-27 18:16:53 Instrument:ISIS2 Swept-Frequency Sounder Resource:NumericalData
This data set consists of ISIS 1 and 2 (International Satellites for Ionospheric Studies)ionograms that have been obtained through a data restoration project. The ISIS ionograms, consisting of a fixed-frequency and a swept-frequency part, were digitized from the original ISIS telemetry tapes. The digitized sounder data consisting of 8-bit receiver-amplitude values collected at a 40 kHz rate contain the time and the frequency associated with each sounder pulse. The frequency of each sounder pulse is determined from a 3rd degree interpolation between the times of the frequency markers as identified in the sounder video during the A/D operation. Included in this data set are the average-resolution ionograms (averages of each 4 successive 40 kHz 8-bit values) in CDF format. Software to read and display the individual CDF files is available at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/software/isis2 These CDF files were produced at NSSDC from the original PI-provided ionogram data. Other ionogram data sets available at NSSDC include the full resolution ionograms and average ionograms both in the PI-provided (OS2) binary format, ASCII header files with pass-specific information and the PCM data which contain header, time, AGC, frequency-marker information and telemetry-level data from all other ISIS instruments. The binary average ionograms and the ASCII header files are available online at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/topside_sounder/ ISIS 1 and 2 data are available to the extent permitted by telemetry scheduling and the location of telemetry stations. A list of stations can be found at http://nssdc.gsfc.nasa.gov/space/isis/isis-table1-new.html and their location on a worldmap is shown in http://nssdc.gsfc.nasa.gov/space/isis/isis_station_lar.GIF (

19) ISIS-2 Topside Sounder Ionograms maxmize
Resource ID:spase://VWO/NumericalData/ISIS2/SFS/Ionogram.PT22S
Start:1969-01-30 14:50:12 Observatory:ISIS 2 Cadence:22 seconds
Stop:1983-12-30 15:19:33 Instrument:ISIS2 Swept-Frequency Sounder Resource:NumericalData
These ionograms were digitized from the original ISIS-2 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. Ionograms with this sample rate are designated as "full" ionograms because they have the full 3.75 km apparent-range resolution. The ionograms used for most analysis, and those available from CDAWeb, were produced by averaging every four samples of the sounder-receiver video amplitude output to yield an average value every 100 microseconds corresponding to an apparent-range resolution of 15 km. These ionogram files are referred to as "average" files with standard resolution. Each ionogram consists of a fixed-frequency and and a swept-frequency portion. The time resolution between ionograms is typically 14 or 22 seconds depending on the frequency sweep range.

20) VOYAGER 1 TITAN RADIO OCCULTATION RAW DATA V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager1/RSS/Saturn/PT0.00001S
Start:1980-11-12 00:00:00 Observatory: Cadence:0.00001 seconds
Stop:1980-11-12 23:59:59 Instrument: Resource:NumericalData
Data Set Overview ================= This data set consists of raw data collected during the Titan radio occultation of Voyager 1 in November 1980 plus ancillary files that might be useful in analysis of those data. The raw data are sampled voltage outputs from receivers tuned to the Voyager carrier frequencies at both S-band and X-band during the occultations. The data have been reduced to give profiles of atmospheric temperature and pressure as a function of height above the surface on both the ingress and egress sides of Titan [LINDALETAL1983] and to make a marginal detection of an ionosphere [BIRDETAL1997]. During the Titan occultation, the Voyager 1 spacecraft provided a coherent, dual-frequency microwave radio signal source. The signal frequency was derived from a precision, onboard Ultra-Stable Oscillator (USO). The spacecraft high-gain antenna (HGA) beamed that signal through the atmosphere of Titan. As the spacecraft moved on its trajectory, the radio signal probed different levels in the atmosphere. An hour later the signals were received by antennas of the NASA Deep Space Network (DSN) on Earth. Because the density of Titan's atmosphere was so poorly known prior to the Voyager encounter, experiment planners did not know how much refractive bending to expect during the observations. Models predicted a range of behaviors from very little bending to so much that the narrow beam from the spacecraft high-gain antenna (HGA) would be deflected away from Earth and the surface occultation would not be seen. Timing uncertainties in the motion of the spacecraft with respect to Titan only complicated the problem. The experiment was implemented with a very small (0.11 deg) fixed HGA offset during the ingress occultation and a large (2.36 deg) offset during egress. These choices, in retrospect, were very good given the atmosphere that was found. Parameters ========== The output of the S-band receiver was a sinusoidal carrier signal embedded in noise -- a voltage with bandwidth approximately 50 kHz and sampled at 300000 samples per second. The X-band receiver output was similar; but, because of greater potential for Doppler drift and prediction uncertainty, its bandwidth was 150 kHz and sampling rate was 300000 samples per second. Voltages typically were in the range +/- 10 volts; but the absolute levels were not calibrated. In fact, they are generally not needed since it is the frequency (or phase) of the signal (rather than amplitude) that is most useful in inferring properties of a neutral atmosphere or ionosphere. The frequency of the USO was known from monitoring during the Jupiter-Saturn cruise (and from post-Saturn observations). Doppler contributions from motions of the spacecraft, Earth, Titan, and other bodies of the solar system were determined jointly with the Voyager Navigation Team. Relativistic Doppler contributions could be estimated from proximity to large masses. Receiver tuning was recorded in POCA (Programmable Oscillator Control Assembly) files, which are included with this archive. Processing ========== No processing per se has been carried out on these data. However, because of the high sampling rate, the 8-bit samples were recorded originally on wide-bandwidth analog video tape. The analog tapes were then replayed later at slower speeds and the digital data were extracted and separated onto computer compatible tapes (CCTs) with S-band and X-band data on different sets of tapes. Because the S-band data had been oversampled originally (300 ksps for a 50 kHz bandwidth), only one of every three samples was saved during the transfer of S-band data to CCTs. This process, known as 'decimation', meant that 300 seconds of data could be stored on an S-band CCT whereas only 100 seconds of X-band data would fit. Because analog recording technology was required to save the high data rate digital samples, there are occasional dropouts in the sample stream. These can be detected by paying special attention to counter fields in data record headers. Two analog recorders (A and B) were available at each DSN complex. Because a single recorder could not capture the entire set of Titan occultation activities, the two were run in parallel with staggered start/stop times. Most data were collected using Recorder A; but Recorder B was used to capture the samples while Recorder A was being reloaded. Data ==== Primary data were delivered to Voyager Radio Science Team members in the form of 30 megabyte (MB) CCTs covering 300 s (S-band) or 100 s (X-band). Each tape had 6000 records of 5056 bytes (56 bytes of header information and 5000 8-bit samples of receiver output voltage). Tapes were numbered sequentially as CCTs were generated from the high density video originals. Tapes with Titan data from Recorder A were numbered VJ6281 through VJ6360; tapes from Recorder B were numbered VJ6361 through VJ6380. Test and calibration data after the Titan encounter were collected on Recorder A and have numbers VJ6589 through VJ6594. The original tape numbering has been preserved in the current file names, which have the form VJnnnnCC.ODR. On tapes where one or more records could not be read, the original has been separated into two or more files. The character 'C' indicates the ordering of these file fragments with 'A' being first (and the default with no tape reading errors), 'B' next, etc. Each Original D

21) VOYAGER 2 SATURN RADIO OCCULTATION RAW DATA V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/RSS/Saturn/PT0.00001S
Start:1981-08-25 20:11:00 Observatory: Cadence:0.00001 seconds
Stop:1981-08-26 08:00:00 Instrument: Resource:NumericalData
Data Set Overview ================ This data set consists of raw data collected during the Saturn radio occultation of Voyager 2 on 26 August 1981, ring scattering data collected during the same time period, test and calibration data collected about 8 hours earlier, and ancillary files that might be useful in analysis of those data. The raw data are sampled voltage outputs from receivers tuned to the Voyager carrier frequencies at both S-band and X-band during the occultation. The data have been reduced to give profiles of temperature and pressure as a function of height in the atmosphere [LINDALETAL1985] and to infer magnetic field orientations in the upper ionosphere [HINSON1984]. During the Saturn occultation, the Voyager 2 spacecraft provided a coherent, dual-frequency microwave radio signal source. The signal frequency was derived from a precision, onboard Ultra-Stable Oscillator (USO). The spacecraft high-gain antenna (HGA) beamed that signal through the atmosphere and rings of Saturn. As the spacecraft moved on its trajectory, the radio signal probed the atmosphere and rings at different radial positions from the center of mass. An hour later the signals were received using a 64-meter antenna of the NASA Deep Space Network (DSN) near Canberra (Australia). To keep the refracted radio beam aimed toward the DSN antenna during the atmospheric occultation, the spacecraft attitude was adjusted so that the high-gain antenna (HGA) was pointed at the virtual image of Earth on Saturn's limb. This ensured that maximum signal strength would be available from the deepest probing. During the deepest part of the atmospheric occultation, the HGA was pointed toward the rings to determine whether signals forward scattered by the ring particles could be detected on Earth. Related data sets of possible interest include: DATA_SET_ID Description ----------------------- -------------------------------- VG1-SSA-RSS-1-ROCC-V1.0 Titan radio occultation raw data VG1-S-RSS-1-REDR-V1.0* Saturn Voyager 1 ingress radio occultation raw data VG1-S-RSS-1-ROCC-V1.0 Saturn Voyager 1 egress radio occultation and ring scattering raw data *tentative DATA_SET_ID assignment Parameters ========== The output of each S-band receiver was a sinusoidal carrier signal embedded in noise -- a voltage with bandwidth approximately 50 kHz and sampled at 300000 samples per second. The X-band receiver output was similar; but, because of greater potential for Doppler drift and prediction uncertainty, its bandwidth was 150 kHz and sampling rate was 300000 samples per second. Voltages typically were in the range +/- 10 volts; but the absolute levels were not calibrated. In fact, they are generally not needed since it is the frequency (or phase) of the signal (rather than amplitude) that is most useful in inferring properties of a neutral atmosphere or ionosphere, and amplitude calibration for ring observations can be obtained by referencing signals to the background radiothermal noise in the data stream. The frequency of the USO was known from monitoring during the Jupiter-Saturn cruise (and from post-Saturn observations). Doppler contributions from motions of the spacecraft, Earth, Saturn, and other bodies of the solar system were determined jointly with the Voyager Navigation Team. Relativistic Doppler contributions could be estimated from proximity to large masses. Receiver tuning was recorded in POCA (Programmable Oscillator Control Assembly) files, which are included with this archive. Processing ========== No processing per se has been carried out on these data. However, because of the high sampling rate, the 8-bit samples were recorded originally on wide-bandwidth analog video tape. The analog tapes were then replayed later at slower speeds and the digital data were extracted onto computer compatible tapes (CCTs) with each receiver channel on a separate set of tapes. Because the S-band data had been oversampled originally (300 ksps for a 50 kHz bandwidth), only one of every three samples was saved during the transfer of S-band data to CCTs. This process, known as 'decimation', meant that 300 seconds of data could be stored on an S-band CCT whereas only 100 seconds of X-band data would fit. Because analog recording technology was required to save the high data rate digital samples, there are occasional dropouts in the sample stream. These can be detected by paying special attention to counter fields in data record headers. Two analog recorders (A and B) were available at each DSN complex. Because a single recorder could not capture the entire set of Saturn occultation activities, the two were run in parallel with staggered start/stop times. Most data were collected using Recorder A; but Recorder B was used to capture the samples while Recorder A was being reloaded. Data ==== Primary data were delivered to Voyager Radio Science Team members in the form of 30 megabyte (MB) CCTs covering 300 s (S-band) or 100 s (X-band). Each tape had 6000 records of 5056 bytes (56 bytes of header information and 5000 8-bit samples of receiver output voltage). Tapes were numbered s

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