Data Set Information
DATA_SET_NAME CASSINI V/E/J/S/SS RPWS EDITED WAVEFORM FULL RES V1.0
DATA_SET_ID CO-V/E/J/S/SS-RPWS-2-REFDR-WFRFULL-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview ================= The Cassini Radio and Plasma Wave Science (RPWS) edited full resolution data set includes all waveform data for the entire Cassini mission. This data set includes uncalibrated values for each waveform channel for each sensor for all times during the mission including the second Venus flyby, the Earth flyby, the Jupiter flyby, interplanetary cruise, and the entire Saturn tour. Data for this data are acquired from the RPWS Waveform Receiver (WFR). Data are presented in a set of time series organized so as to have fixed-length records for ease in data handling. Data from the different WFR modes (i.e. 2.5-kHz and 26 Hz modes) are segregated into separate files. This data set includes all waveform data acquired by the RPWS. 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. The waveform data provide the highest resolution data from the RPWS instrument in the form of a set of waveform series for these two bandwidths and can be used, when data from two electric and three magnetic sensors are available, to perform wave-normal analyses on various plasma wave phenomena. These data can be used in their original time domain in order to look for solitary features such as dust impacts or electrostatic solitary waves. Or, they can be transformed into the frequency domain in order to examine the detailed time and spectral evolution of plasma waves or radio emissions or to do the wave-normal analysis. Usually, this data set includes time series measurements from more than one (up to five) sensors at a time and the samples are made simultaneously for all five sensors. Parameters ========== This data set comprises time series of data numbers related to the potential difference at the preamp input to the RPWS. The data numbers can be calibrated with the use of supplied algorithms and calibration factors to generate a time series of electric or magnetic field waveforms in units of volts/meter or nanotesla. Because the primary purpose of the WFR is to support wave-normal analyses, the typical configuration of this receiver uses the 5-sensor combination mentioned above. The waveforms can be acquired in one of two modes: 1. 2.5-kHz mode: 0.003 - 2.5 kHz, 140 microsecond sampling rate 2. 26-Hz mode: 1 - 26 Hz, 10 msec sampling rate For each mode, one, two, three, or five individual sensors can be selected. The samples are made simultaneously on each of the sensors so as to preserve information on the phase relationships between signals on the various sensors. Typically, data are acquired in time series with length of a multiple of 512 12-bit samples, usually with this length set to 2048 samples. For the 2.5-kHz mode, this results in time series of duration about 287 msec and for the 26-Hz mode, the duration of the waveform series is typically about 20 s. A new waveform series can be acquired as often as once per approximately 20 seconds but typically once every several minutes. Hence, the duty cycle for this mode can be very small (e.g. 287 msec out of 300 sec or about 0.1 percent for the 2.5 kHz mode or about 7 percent for the 26-Hz mode) with typical sample lengths. In some instrument modes the WFR is exercised at a much higher duty cycle, at rates of once or twice per minute, improving the duty cycle considerably. Processing ========== Data in this data set were processed by the use of a number of software programs which assemble segmented mini-packets in the raw telemetry packets into complete sets and de-compress the data that were compressed by one of several possible onboard compression schemes. These data may be calibrated using supplied calibration factors and algorithms as well as sample code provided. Data ==== The RPWS full resolution waveform data set is organized by receiver mode and time series sample length in order to use files with fixed record lengths. Each time series is a record in a file with header information on time, sensor, and receiver gain (required for calibration). Separate files will be maintained for each instrument mode and sample length. Ancillary Data ============== Ancillary data included with this data set collection include a series of files that describe the modes of the RPWS as a function of time and provide a time- ordered listing of Instrument Expanded Block (IEB) trigger commands (the mode by which the RPWS is reconfigured). Also a detailed description of each of the modes (or IEBs) is provided. Other data which are ancillary to this data set but which are archived separately from this collection are the Navigation and Ancillary Information Facility's SPICE kernels describing the position and attitude of Cassini and various solar system bodies as a function of time. Coordinate System ================= The data in this data set are measurements of wave electric and magnetic fields measured by the RPWS electric and magnetic sensors. These fields are presented as detected by the sensors and are not rotated into any other coordinate system. If desired the SPICE kernels can be used with the SPICE toolkit to convert from the spacecraft frame to virtually any frame which may be of use in analyzing these data. However, for many purposes, the wave amplitudes are extremely useful and may be entirely adequate with no coordinate transformations at all. Wave normal analysis typically requires that the wave data and vector magnetic field from the MAGNETOMETER instrument be used in a common coordinate system. Software ======== Sample code is provided with these data which demonstrates how to read these files in order to build a set of waveform time series. Algorithms and sample code are provided which convert from data number to either electric or magnetic field strength (units of volt/meter or nanotesla). The sample code and algorithms are found in the EXTRAS/SOFTWARE directory. A description of how to access and calibrate these data is included in WBRWFR.TXT in the DOCUMENT directory. Also see the RPWSCAL document in the same directory. Media/Format ============ These data are supplied to the Planetary Data System on DVD-R media using formats and standards of the PDS for such media.
DATA_SET_RELEASE_DATE 2018-07-01T00:00:00.000Z
START_TIME 1997-10-25T12:00:00.000Z
STOP_TIME 2017-09-15T12:00:00.000Z
MISSION_NAME CASSINI-HUYGENS
MISSION_START_DATE 1997-10-15T12:00:00.000Z
MISSION_STOP_DATE 2017-09-15T12:00:00.000Z
TARGET_NAME VENUS
EARTH
DIONE
HYPERION
TITAN
PHOEBE
SOLAR SYSTEM
RHEA
TETHYS
SATURN
ENCELADUS
MIMAS
IAPETUS
JUPITER
TARGET_TYPE PLANET
SATELLITE
PLANETARY SYSTEM
INSTRUMENT_HOST_ID CO
INSTRUMENT_NAME RADIO AND PLASMA WAVE SCIENCE
INSTRUMENT_ID RPWS
INSTRUMENT_TYPE PLASMA WAVE SPECTROMETER
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS ARCHIVED - ACCUMULATING
CONFIDENCE_LEVEL_NOTE Confidence Level Overview ========================= This data set contains all waveform data for the Cassini RPWS instrument for the interval described in the product label files. Every effort has been made to ensure that all data returned to JPL from the spacecraft is included and that the calibration information is accurate. Review ====== The RPWS full resolution waveform data will be reviewed internally by the Cassini RPWS team prior to release to the PDS. The data set will also be peer reviewed by the PDS. Data Coverage and Quality ========================= All data in the stated interval are included, to the best of our knowledge and attempts to determine completeness. In general, these data were acquired during early tour for the following intervals: 1. Antenna deployment 1997-10-25T00:00 - 1997-10-26T05:30 2. Instrument Checkout 1998-12-30T09:10 - 1999-01-19T05:40 3. Venus 2 flyby 1999-06-24T09:08 - 1999-06-24T21:20 4. Earth flyby 1999-08-13T17:39 - 1999-09-14T22:20 *Actual interval for science data is much shorter than this. Beginning in February of 2000 the instrument was operated more-or-less continuously; two gaps of the order of six weeks were incurred for the purposes of loading new attitude control and command and data system flight software, gaps of a few days each were incurred approximately twice per year because of Huygens Probe testing, and gaps of several days in duration occurred during solar conjunction periods prior to 2002. Remaining gaps are due to spacecraft anomaly resolution or simply to downlink gaps, some of which were imposed by limitations on DSN station availability. During the time interval after February 2002, the wideband data were acquired during such times when the onboard solid state recorder and the downlink capability could support the high data volumes required for these data. Typically, waveform data are not acquired during the interplanetary cruise phase. However, they are acquired more regularly at low duty cycles during tour and near some of the planetary flybys en route. A user would find events of interest in the more continuous low rate data and consult the ancillary sequence information provided to determine the existence of waveform data in an appropriate mode for that event. Further, a graphical browse data set is supplied with the archive to allow the user to look at frequency-time spectrograms directly in order to find events or phenomena of interest. This browse system will point the user to the data files containing the data of interest. Limitations =========== Beginning approximately with Saturn orbit insertion in early July 2005, the RPWS has shown increasing sensitivity in its electric field measurements below 2 kHz to interference from the spacecraft reaction wheels. The wheels are a source of electromagnetic interference in the magnetic channels at frequencies directly related to the rotation rate of the wheels due to a residual magnetic moment in the wheels. This level was predicted before launch and has been basically constant through flight. However, at the earliest opportunity to observe the interference of the wheels on the electric field measurements, there was essentially no detectable level of interference. However, after orbit insertion, it became clear with increasing time that the wheels were becoming an increasing source of interference in the electric field measurements at about 2 kHz and below. As of late 2005, the amplitude of this interference is of the order of 30 or 40 dB above the instrument noise level. The relation of the frequency of the electric interference to the rotation rate of the wheels is less direct than for the magnetic interference. There is a general correspondence, but not in detail. It appears that there are some frequencies more susceptible to the interference than others and when the wheel speed approaches these 'resonances', the interference becomes more visible. A working model for this interference proposes that radiation effects on some part(s) of the spacecraft, perhaps the thermal blankets, reduce the conductivity. Small vibrations of this part(s), then, with some residual differential charging then result in the electric field interference. This model is not confirmed and the true explanation of the interference is unknown, but the effects significantly complicate the interpretation of the electric field spectrum below 2 kHz. SCET Miscalculation =================== Version 1 of CORPWS data 2008-12-28 through 2011-06-30 were processed using invalid SPICE spacecraft clock kernels. Specifically the SCLKs which spice was asked to convert to SCETs were outside the valid correlation region. The error was subtle at first but continued to grow as SCLKs further from the correlated region were converted to SCETs. The net result was that incorrect SCET values were placed into the product files and product label files for these dates. The issue has been corrected and no longer affects any CORPWS datasets available from the PDS. The following table lists the maximum SCET errors by date.Start Date Stop Date Version Release Date Max SCET error----------- ---------- -------- ------------- ---------------2008-12-28 2009-01-12 1 2009-09-25 1.2 seconds2009-01-13 2009-01-29 1 2009-12-17 1.3 seconds2009-01-30 2009-02-12 1 2009-12-17 1.3 seconds2009-02-13 2009-03-01 1 2009-12-17 1.4 seconds2009-03-02 2009-03-29 1 2009-12-17 1.5 seconds2009-03-30 2009-04-19 1 2009-12-17 1.5 seconds2009-04-20 2009-05-16 1 2009-12-18 1.6 seconds2009-05-17 2009-06-12 1 2009-12-18 1.7 seconds2009-06-13 2009-06-26 1 2009-12-18 1.7 seconds2009-06-27 2009-07-09 1 2009-12-18 1.7 seconds2009-07-10 2009-07-25 1 2010-06-28 1.8 seconds2009-07-26 2009-08-17 1 2010-06-28 1.9 seconds2009-08-18 2009-09-09 1 2010-06-29 1.9 seconds2009-09-10 2009-10-01 1 2010-06-30 1.9 seconds2009-10-02 2009-10-21 1 2010-09-21 1.8 seconds2009-10-22 2009-11-14 1 2010-09-21 1.9 seconds2009-11-15 2009-12-10 1 2010-09-21 2.0 seconds2009-12-11 2009-12-23 1 2010-09-21 2.0 seconds2009-12-24 2010-01-13 1 2010-09-21 2.1 seconds2010-01-14 2010-01-23 1 2010-09-21 2.2 seconds2010-01-24 2010-02-02 1 2010-12-22 2.2 seconds2010-02-03 2010-02-17 1 2010-12-22 2.2 seconds2010-02-18 2010-02-27 1 2010-12-22 2.2 seconds2010-02-28 2010-03-11 1 2010-12-22 2.3 seconds2010-03-12 2010-03-22 1 2010-12-22 2.3 seconds2010-03-23 2010-03-31 1 2010-12-22 2.4 seconds2010-04-01 2010-04-16 1 2010-12-22 2.5 seconds2010-04-17 2010-04-29 1 2010-12-22 2.6 seconds2010-04-30 2010-05-10 1 2010-12-22 2.6 seconds2010-05-11 2010-05-25 1 2010-12-22 2.7 seconds2010-05-26 2010-06-08 1 2010-12-22 2.8 seconds2010-06-09 2010-06-25 1 2010-12-23 2.9 seconds2010-06-26 2010-08-07 1 2011-03-23 3.3 seconds2010-08-08 2010-09-08 1 2011-03-23 3.6 seconds2010-09-09 2010-10-15 1 2011-03-23 3.9 seconds2010-10-16 2010-11-29 1 2011-09-29 4.1 seconds2010-11-30 2011-01-03 1 2011-09-30 2.4 seconds2011-01-04 2011-02-13 1 2011-12-21 2.7 seconds2011-02-14 2011-03-24 1 2011-12-21 5.3 seconds2011-03-25 2011-04-24 1 2011-12-21 7.3 seconds2011-04-25 2011-05-09 1 2011-12-21 8.3 seconds2011-05-10 2011-05-26 1 2011-12-22 9.4 seconds2011-05-27 2011-06-12 1 2011-12-22 10.5 seconds2011-06-13 2011-06-30 1 2011-12-22 11.7 seconds Only data from 2008-12-28 through 2011-06-30 with VERSION_VERSION_ID = 1 are affected. If VERSION_VERSION_ID is greater than 1, or the date is before 2008-12-28, or the the date is after 2011-06-30, then the data in question is unaffected by this issue.
CITATION_DESCRIPTION Kurth, W.S., W.T. Robison, and L.J. Granroth, CASSINI V/E/J/S/SS RPWS EDITED WAVEFORM FULL RES V1.0, CO-V/E/J/S/SS-RPWS-2-REFDR-WFRFULL-V1.0, NASA Planetary Data System, 2004.
ABSTRACT_TEXT The Cassini Radio and Plasma Wave Science (RPWS) edited full resolution data set includes all waveform data for the entire Cassini mission. This data set includes uncalibrated values for each waveform channel for each sensor for all times during the mission including the second Venus flyby, the Earth flyby, the Jupiter flyby, interplanetary cruise, and the entire Saturn tour. Data for this data set are acquired from the RPWS Waveform Receiver (WFR). Data are presented in a set of time series organized so as to have fixed-length records for ease in data handling. Data from the different WFR modes (i.e. 2.5-kHz and 26 Hz modes) are segregated into separate files. This data set includes all waveform data acquired by the RPWS. 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. The waveform data provide the highest resolution data from the RPWS instrument in the form of a set of waveform series for these two bandwidths and can be used, when data from two electric and three magnetic sensors are available, to perform wave-normal analyses on various plasma wave phenomena. These data can be used in their original time domain in order to look for solitary features such as dust impacts or electrostatic solitary waves. Or, they can be transformed into the frequency domain in order to examine the detailed time and spectral evolution of plasma waves or radio emissions or to do the wave-normal analysis. Usually, this data set includes time series measurements from more than one (up to five) sensors at a time and the samples are made simultaneously for all five sensors.
PRODUCER_FULL_NAME DR. WILLIAM S. KURTH
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