NSSDCA ID: PSFP-00355
Availability: Archived at NSSDC, accessible from elsewhere
This description was generated automatically using input from the Planetary Data System.
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.
These data are available on-line from the Planetary Data System (PDS) at:
https://pds-ppi.igpp.ucla.edu/data/CO-V_E_J_S_SS-RPWS-2-REFDR-WFRFULL-V1.0/
Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II
Name | Role | Original Affiliation | |
---|---|---|---|
Prof. Donald A. Gurnett | Data Provider | University of Iowa | |
Dr. William S. Kurth | General Contact | University of Iowa | wsk@space.physics.uiowa.edu |