2.7.1 https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions spase://NASA/NumericalData/IMAGE/RPI/DS/PT5M NASA NumericalData IMAGE RPI Dynamic Spectrogram data in CDF at NASA CDAWeb IM_K1_RPI https://doi.org/10.48322/tqpm-9804 2025-12-04T13:29:33Z 2021-04-27T15:38:11 Only known prior ReleaseDate of the metadata 2023-07-30T12:34:56.789 Added DOI and PublicationInfo minted by LFB, metadata versioned up to SPASE 2.6.0, reviewed by LFB 20230727 2025-10-02T15:12:00Z Updated PublishedBy name to match ROR Registry. Added ResourceType and NamingAuthority. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. Matched version number in schemaLocation attribute to updated value in Version tag. ZCB 2025-12-04T13:29:33Z Added MetadataRightsList and RightsList(s). Updated to 2.7.1. ZCB 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 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. Reinisch, Bodo, W.; Galkin, Ivan, A. 2023-01-01T00:00:00 Space Physics Data Facility spase://SMWG/Person/Bodo.W.Reinisch PrincipalInvestigator spase://SMWG/Person/Ivan.A.Galkin DataProducer TechnicalContact spase://SMWG/Person/Lee.Frost.Bargatze MetadataContact IMAGE RPI Instrument Page https://image.gsfc.nasa.gov/rpi/ IMAGE RPI Instrument page maintained by NASA GSFC with RPI facts, description, team, data, documents, discoveries, and related links sections en IMAGE RPI Instrument Page at UML https://ulcar.uml.edu/rpi.html 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 en IMAGE RPIAnywhere Download Page https://ulcar.uml.edu/Installation/install_all.htm RPIAnywhere software download page, including BinBrowser (RPI data analysis tool) and EdRPI (RPI mission planning tool) en spase://NASA/DisplayData/IMAGE/RPI/DS/P1D DerivedFrom spase://VWO/NumericalData/IMAGE/RPI/CDF_DS_PT5M spase://VWO/NumericalData/IMAGE/RPI/DS.PT5M spase://VSPO/NumericalData/IMAGE/RPI/DS.PT5M spase://VSPO/NumericalData/IMAGE/RPI/DS/PT5M spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Online Open https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products FTPS from SPDF (not with most browsers) ftps://spdf.gsfc.nasa.gov/pub/data/image/rpi/rpi_k1/ FTP access to repository of IMAGE RPI passive wave measurements (dynamic spectrograms) in CDF format at NASA CDAWeb. en HTTPS from SPDF https://spdf.gsfc.nasa.gov/pub/data/image/rpi/rpi_k1/ http access to repository of IMAGE RPI passive wave measurements (dynamic spectrograms) in CDF format at NASA CDAWeb. en CDAWeb https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=IM_K1_RPI&index=sp_phys IM_K1_RPI Access to ASCII, CDF, and plots via NASA/GSFC CDAWeb CDF None https://cdaweb.gsfc.nasa.gov/pub/data/image/rpi/rpi_k1/$Y im_k1_rpi_$Y$m$d_$v.cdf 9449 MByte 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. spase://SMWG/Repository/NASA/GSFC/SPDF Online Open CDAWeb Programmatic Data Access https://cdaweb.gsfc.nasa.gov/WS/cdasr/1/dataviews/sp_phys/datasets/IM_K1_RPI/clientLibraryExample/ IM_K1_RPI Access to this data from common programming environments. Note: this AccessInformation element was added by HDPWS. Binary 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. spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Online Open https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products CDAWeb HAPI Server https://cdaweb.gsfc.nasa.gov/hapi IM_K1_RPI Web Service to this product using the HAPI interface. CSV 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. Calibrated 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. spase://SMWG/Instrument/IMAGE/RPI Waves.Passive Spectrum ElectricField 2000-04-21T20:24:42Z 2005-12-18T07:50:00Z 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. PT5M PT72S RadioFrequency Earth.Magnetosphere Earth.NearSurface.Plasmasphere Earth.NearSurface.AuroralRegion Earth.NearSurface.PolarCap Heliosphere.Inner (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. Dynamic Spectrogram Spectrogram AKR Auroral hiss Auroral Kilometric Radiation Chorus Continuum radiation Myriametric radiation Plasmaspheric Hiss Solar radio burst Terrestrial Kilometric Radiation TKR Type II Solar radio burst Type III Solar radio burst UHR Upper hybrid resonance VLF Station VLF Transmitter Whistler Voltage spectral density 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. PT5M dB(V/root-Hz) Spectrogram Frequency, kHz Vertical -1 0 I4 3 1100 LogScale Spectrogram Universal Time Horizontal Spectrogram X Amplitude, dB(V/root-Hz) ColorBar 0 1 I4 -144 -96 LinearScale Spectrogram Y Amplitude, dB(V/root-Hz) ColorBar 0 2 I4 -144 -96 LinearScale Spectrogram Z Amplitude, dB(V/root-Hz) ColorBar 0 3 I4 -144 -96 LinearScale Spectrogram XY Amplitude, dB(V/root-Hz) ColorBar 0 4 I4 -144 -96 LinearScale 256 4 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. Frequency Dimension -1 0 Frequency Antenna Dimension 0 -1 Voltage Spectral Density in antenna X 0 1 Amplitude_X dB(V/root-Hz) -190 -70 -1.0e+031 Voltage Spectral Density in antenna Y 0 2 Amplitude_Y dB(V/root-Hz) -190 -70 -1.0e+031 Voltage Spectral Density in antenna Z 0 3 Amplitude_Z dB(V/root-Hz) -190 -70 -1.0e+031 Voltage Spectral Density in combined antennas X and Y 0 4 Amplitude_XY dB(V/root-Hz) -190 -70 -1.0e+031 PlasmaWaves Magnitude Spectral Pseudo Intensity RadioFrequency 3 1009 kHz List of Frequencies Frequency 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. PT5M kHz 256 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. Frequency -1 3 3000 -1.0e+031 Other Number of Frequencies NumFreqs Number of frequencies in the sweep, see "List of Frequencies 0 256 -32768 Other Start Time Epoch Epoch timestamp of the beginning of the spectrogram measurement. Use Measurement Duration to obtain time of measurement stop. 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. PT5M ms Temporal Measurement Duration Duration_ms Duration of one spectrogram measurement. ms Temporal Number of Repetitions NumRepetitions 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) 3 8 -128 Other Base Gain BaseGain 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. 0 16 255 Other Measurement Program Specification ProgramSpecs 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. PT5M 25 Linear 1D array of values used to configure RPI instrument for a measurement mode. RPI Parameter -1 Other