SPASE version 2.2.0
Numerical Data Product: RPI Dynamic Spectrogram data in CDF at NASA CDAWeb
- Resource ID
- spase://VWO/NumericalData/IMAGE/RPI/DS.PT5M
- Name
- RPI Dynamic Spectrogram data in CDF at NASA CDAWeb
- Alternate name
- Description
-
RPI passive wave measurement capturing voltage spectral density of the radio emissions in space as a function of frequency, typically between 3 and 1009 kHz. This operating frequency range was selected by the RPI team to provide optimal temporal resolution of the wave observations. Commonly used in the analysis of noise generators, spectral density is a frequency-dependent characteristic that describes how much power is generated by the emission source in a 1 Hz bandwidth. The original description of emissions was done in terms of thermal noise measurements, though the same approach also applies to non-thermal emissions such as AKR. CDF_DS_PT5M stores calibrated data from all three RPI antennas X, Y, and Z individually and a combined X+Y antenna channel. The data are presented as the Voltage Spectral Density (VSD), which is the root of power spectral density, measured in [V/root-Hz] units. Note that conversion of antenna voltage to electric field strength depends on the effective length of the receive antenna, and such conversion is not performed here. (See spase://SMWG/Instrument/IMAGE/RPI for a time history of the lengths of the three mutually orthogonal RPI dipole antennas.) RPI is capable of detecting input radio emissions above its noise floor of 5 nV/root-Hz, which is determined by the internal white noise of the RPI antenna pre-amplifiers. The VSD in RPI spectrogram data is presented in dB relative to 1 V/root-Hz (logarithmic scale), units of dB(V/root-Hz). The RPI instrument noise floor is 5 nV/root-Hz = -166 dB(V/root-Hz) at the receiver input. Software suggested by the science team for CDF file visualization: (1) Plotting tool at the CDAWeb portal, (2) For analysis beyond static image inspection, including color scale optimization, zooming, text export, alternative data representations in physical units, detailed frequency and time information, overlaid model fpe and fce graphs, and EPS quality figures, use BinBrowser software at UML, http://ulcar.uml.edu/rpi.html
- Additional information
-
- IMAGE RPI Instrument Page
-
IMAGE RPI Instrument page maintained by NASA GSFC with RPI facts, description, team, data, documents, discoveries, and related links sections
- Language
- en
- IMAGE RPI Instrument Page at UML
-
IMAGE RPI Instrument page maintained by University of Massachusetts Lowell with RPI description, team, software downloads, software user guides, access to CORPRAL automated prospecting results, mission planning tools and commanding guide, data model descriptions for Level 0 and 1, sonification files of 2003 Halloween storm, and useful links
- Language
- en
- IMAGE RPIAnywhere Download Page
-
RPIAnywhere software download page, including BinBrowser (RPI data analysis tool) and EdRPI (RPI mission planning tool)
- Language
- en
- Acknowledgement
-
Users please acknowledge Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center and RPI Principal Investigator Prof. B. W. Reinisch of the University of Massachusetts Lowell for making these CDF files available.
- Contact
-
Role Person 1. Principal investigator Prof. Bodo W. Reinisch 2. Data producer
Technical contactDr. Ivan A. Galkin - Release date
- 2012-02-24 17:31:03
- Association
- Prior IDs
- spase://VWO/NumericalData/IMAGE/RPI/CDF_DS_PT5M
- Repository
-
- Name
- CDAWeb Data Repository FTP Interface
- Availability
- Online
- Access rights
- Open
- URL
-
- CDAWeb FTP access to IMAGE RPI passive wave measurements (dynamic spectrograms)
-
FTP access to repository of IMAGE RPI passive wave measurements (dynamic spectrograms) in CDF format at NASA CDAWeb.
- Language
- en
- CDAWeb access portal to IMAGE RPI passive wave measurements (dynamic spectrograms)
-
Repository of IMAGE RPI passive wave measurements (dynamic spectrograms) in CDF format at NASA CDAWeb, accessible via web interface. Name of the data resource: IM_K1_RPI.
- Language
- en
- Format
- CDF
- Encoding
- None
- File size
- 9449 MByte
- Acknowledgement
-
Users please acknowledge Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center and RPI Principal Investigator Prof. B. W. Reinisch of the University of Massachusetts Lowell for making these CDF files available.
- Processing level
- Calibrated
- Provider processing level
- Calibrated data in physical units. Spacecraft MET to UT is converted using history of IMAGE observatory clock drift. Added data items: Combined XY channel VSD value is obtained as the length of a vector formed by X and Y channel VSD components; spacecraft spin modulation is not seen in XY channel data. Data reduction from full resolution telemetry dataset to this Level-1 dataset: (1) Selection of one sample out of 8 available in TTD databin, (2) removal of cross-phase and cross-power terms available in TTD databin.
- Instrument
- Radio Plasma Imager (RPI)
- Measurement type
- Electric field
- Spectrum
- Passive waves
- Temporal description
-
- Start date
- 2000-04-21 20:24:42
- Stop date
- 2005-12-18 07:50:00
- Note
-
In Cadence below, the 5 minutes refers to the nominal interval between measurements. Actual cadence of passive measurement varied between 3 to 6 minutes depending on the RPI science plan and design of measurement schedules.
- Cadence
- 5 minutes
- Exposure
- 1 minute 12 seconds
- Spectral range
- RadioFrequency
- Observed regions
- Earth.Magnetosphere
- Earth.NearSurface.AuroralRegion
- Earth.NearSurface.Plasmasphere
- Earth.NearSurface.PolarCap
- Heliosphere.Inner
- Caveats
-
(A) Known artifacts of dynamic spectrograms are (1) a horizontal line at 20 kHz where the frequency stepping changes from linear to logarithmic, and (2) a variety of interference sources internal to the IMAGE observatory appear as horizontal lines on the dynamic spectrograms including, most prominently, 101 kHz; additional lines appear at 63 kHz and its 126 kHz 2nd harmonic (battery charger), at times a broad band is also present between 160 and 200 kHz due to the torque rod operation, and a narrow line appears at 75 kHz due to the S-band transponder. Other known intereferer lines are 150 kHz, 200 kHz, and 240 kHz (deck plate heaters and other onboard instruments), but these lines are usually not present in the measurement. (B) When the spectrogram is plotted, the pixel size is made wide enough to fill the gaps caused by the 5 minute cadence of the measurements. (C) Comparison of voltage spectral density with other space receiver data has to consider differences in the antenna configurations.
- Keywords
- AKR
- Auroral Kilometric Radiation
- Auroral hiss
- Chorus
- Continuum radiation
- Dynamic Spectrogram
- Myriametric radiation
- Plasmaspheric Hiss
- Solar radio burst
- Spectrogram
- TKR
- Terrestrial Kilometric Radiation
- Type II Solar radio burst
- Type III Solar radio burst
- UHR
- Upper hybrid resonance
- VLF Station
- VLF Transmitter
- Whistler
Parameters
Parameter #1
- Name
- Voltage spectral density
- Description
-
Commonly used in circuit analysis, Power Spectral Density (PSD) describes how much noise power is generated by the emission source in a 1 Hz bandwidth. Dynamic Specrtograms use Voltage Spectral Density (VSD), which is root of PSD, measured in V/root-Hz units. The VSD in RPI spectrograms is presented in dB relative to 1 V/root-Hz (logarithmic scale), units of dB(V/root-Hz). On average, the RPI instrument noise floor is 5 nV/root-Hz = -166 dB(V/root-Hz) at the receiver input.
- Cadence
- 5 minutes
- Units
- dB(V/root-Hz)
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- Frequency, kHz
- Rendering axis
- Vertical
- Index
- -1 0
- Format
- I4
- Scale minimum
- 3
- Scale maximum
- 1100
- Scale type
- Log scale
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- Universal Time
- Rendering axis
- Horizontal
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- X Amplitude, dB(V/root-Hz)
- Rendering axis
- Color bar
- Index
- 0 1
- Format
- I4
- Scale minimum
- -144
- Scale maximum
- -96
- Scale type
- Linear scale
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- Y Amplitude, dB(V/root-Hz)
- Rendering axis
- Color bar
- Index
- 0 2
- Format
- I4
- Scale minimum
- -144
- Scale maximum
- -96
- Scale type
- Linear scale
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- Z Amplitude, dB(V/root-Hz)
- Rendering axis
- Color bar
- Index
- 0 3
- Format
- I4
- Scale minimum
- -144
- Scale maximum
- -96
- Scale type
- Linear scale
- Rendering hints
-
- Display type
- Spectrogram
- Axis label
- XY Amplitude, dB(V/root-Hz)
- Rendering axis
- Color bar
- Index
- 0 4
- Format
- I4
- Scale minimum
- -144
- Scale maximum
- -96
- Scale type
- Linear scale
- Structure
-
- Size
- 256 4
- Description
-
One measurement is an array of voltage spectral density (VSD) values, as functions of frequency, obtained during the frequency sweep. For each operating frequency, four values of VSD are reported: (1) antenna X, (2) antenna Y, (3) antenna Z, (4) combined antennas X and Y to remove spacecraft spin modulation. Resulting structure is a linear 256 x 4 array. Number of frequencies for which the voltage spectral density values are given depends on the choice of frequency sweep (see "List of Frequencies" and "Number of Frequencies" parameters and their description below). The "256" value stated in Size is the upper limit. Note that Index "0" means a wild card ("don't care"), index "-1" means the whole dimension.
- Elements
-
Index Name Parameter key Units Valid min Valid max Fill value -1 0 Frequency Dimension Frequency 0 -1 Antenna Dimension 0 1 Voltage Spectral Density in antenna X Amplitude_X dB(V/root-Hz) -190 -70 -1.0e+031 0 2 Voltage Spectral Density in antenna Y Amplitude_Y dB(V/root-Hz) -190 -70 -1.0e+031 0 3 Voltage Spectral Density in antenna Z Amplitude_Z dB(V/root-Hz) -190 -70 -1.0e+031 0 4 Voltage Spectral Density in combined antennas X and Y Amplitude_XY dB(V/root-Hz) -190 -70 -1.0e+031
- Wave type
- Plasma waves
- Quantity
- Intensity
- Qualifier
- Magnitude
- Spectral
- Pseudo
- Frequency range
-
- Spectral range
- RadioFrequency
- Low frequency
- 3
- High frequency
- 1009
- Units
- kHz
Parameter #2
- Name
- List of Frequencies
- Parameter key
- Frequency
- Description
-
List of operating frequencies at which sample data were collected to obtain VSD values. Actual frequency values vary from measurement to measurement depending on the choice of frequency sweep. Early in the mission, a variety of frequency sweeps were tested until March 27, 2001 when they were streamlined to three basic types: PROGRAM-23: linear sweep from 3 to 20 kHz with 400 Hz step (13 sec running time), PROGRAM-26: logarithmic sweep from 20 to 1009 kHz with 2% stepping (59 sec running time), and PROGRAM-25: logarithmic sweep from 20 to 300 kHz with 2% stepping (37 sec running time). Most commonly used since April 2001, PROGRAM-23 and PROGRAM-26 combination takes 72 sec to complete one sweep from 3 to 1009 kHz. Other frequency sweeps were also exercised, in addition to the three basic types, during experiments on detection of signals from the ground VLF transmitters. For a greater detail on the RPI measurement programming cases in the dynamic spectrogram mode, please refer to RPI operational logs available as part of the RPIAnywhere software package at http://ulcar.uml.edu/rpi.html.
- Cadence
- 5 minutes
- Units
- kHz
- Structure
-
- Size
- 256
- Description
-
Linear 1D array of frequency values, up to 256. Actual number of frequencies for which the voltage spectral density values were measured depends on the choice of frequency sweep (see "Number of Frequencies" parameter and its description below). The "256" value stated in Size is the upper limit.
- Elements
-
Index Name Valid min Valid max Fill value -1 Frequency 3 3000 -1.0e+031
- Parameter type
- Other
Parameter #3
- Name
- Number of Frequencies
- Parameter key
- NumFreqs
- Description
-
Number of frequencies in the sweep, see "List of Frequencies"
- Valid minimum
- 0
- Valid maximum
- 256
- Fill value
- -32768
- Parameter type
- Other
Parameter #4
- Name
- Start Time
- Parameter key
- Epoch
- Description
-
Epoch timestamp of the beginning of the spectrogram measurement. Use Measurement Duration to obtain time of measurement stop.
- Caveats
-
The 5 minutes refers to the nominal interval between measurements. Actual cadence of passive measurement varied between 3 to 6 minutes depending on the RPI science plan and design of measurement schedules.
- Cadence
- 5 minutes
- Units
- ms
- Parameter type
- Temporal
Parameter #5
- Name
- Measurement Duration
- Parameter key
- Duration_ms
- Description
-
Duration of one spectrogram measurement.
- Units
- ms
- Parameter type
- Temporal
Parameter #6
- Name
- Number of Repetitions
- Parameter key
- NumRepetitions
- Description
-
Number of looks at each of the spectrogram frequencies, encoded. Encoding: stored number N is used as power of 2 (i.e., 2**N is actual number of repetitions)
- Valid minimum
- 3
- Valid maximum
- 8
- Fill value
- -128
- Parameter type
- Other
Parameter #7
- Name
- Base Gain
- Parameter key
- BaseGain
- Description
-
Instrument setting describing receiver gains in X/Y and Z channels, encoded. See data model description at http://ulcar.uml.edu/rpi.html for additional details on base gain decoding procedure.
- Valid minimum
- 0
- Valid maximum
- 16
- Fill value
- 255
- Parameter type
- Other
Parameter #8
- Name
- Measurement Program Specification
- Parameter key
- ProgramSpecs
- Description
-
List of 25 parameter values that specify RPI instrument configuration during the measurement. For further detail on parameter value interpretation see data model description document at http://ulcar.uml.edu/rpi.html.
- Cadence
- 5 minutes
- Units
- Structure
-
- Size
- 25
- Description
-
Linear 1D array of values used to configure RPI instrument for a measurement mode.
- Elements
-
Index Name -1 RPI Parameter
- Parameter type
- Other