Search results 4 matches in 0.001 seconds
Showing 1 - 4

1) STEREO WAVES (SWAVES) PDF Dynamic Spectrogram Plots both Ahead and Behind s/c maxmize
Resource ID:spase://VWO/DisplayData/STEREO/SWAVES/DS.Color.PDF.P1D
Start:2006-10-27 20:24:42 Observatory:STEREO A Cadence:1 minute
Stop:2014-04-23 01:02:24 Instrument:STEREO-A Waves (SWAVES) Resource:DisplayData
This dataset contains 24 hour duration dynamic spectrogram plots from the combined STEREO A and B Waves instrument. The plots are provided in several file formats (PNG, Postscript and PDF) and there are renditions in color and grayscale with and without additional lines of time series data indicating the instrument operating status. These plots all reside within the same directory structure subdivided by year. The "new" subdirectory contain plots at a higher resolution but currently are not available for dates early in the mission. These data consist of output from the SWAVES HFR and LFR receivers. ? the High Frequency Receivers (HFR) - for spectral analysis and direction finding of radio noise generated from a few solar radii (16 MHz) to about half an Astronomical Unit (125 kHz) ? the Low Frequency Receiver (LFR) - for spectral analysis and direction finding from about half an Astronomical Unit (160 kHz) to one AU (2.5 kHz).

2) Ulysses URAP Daily Color Dynamic Spectrogram Plot maxmize
Resource ID:spase://VWO/DisplayData/Ulysses/URAP/DS.P1D
Start:1990-11-03 19:30:00 Observatory:Ulysses Cadence:128 seconds
Stop:2007-11-26 18:30:00 Instrument:Unified Radio and Plasma Waves (STO/URAP) Resource:DisplayData
from URAP Users Notes: Guide To The Archiving Of Ulysses Radio And Plasma Wave Data by Roger Hess, Robert MacDowall, Denise Lengyel-Frey March 15, 1995 - version 1.0 revised March 24, 1999 - version 1.1 revised June 8, 1999 - version 1.2 These color plots present URAP radio and plasma wave data in a format referred to as dynamic spectra. For the daily plots, the time resolution is 128 seconds, providing high-time resolution across the entire frequency range of the URAP receivers. The 10-day plots use 10-minute resolution data, which permits good detection of bursty wave activity. The 26-day plots use 1-hour resolution data; these plots correspond to the other Ulysses 26-day plot intervals, but the ability to identify wave activity is reduced. The power of the electric or magnetic field is shown in color as a 2-dimensional function of time and frequency. The plots include data from the URAP Radio Astronomy Receivers (RAR), Plasma Frequency Receiver (PFR), and Waveform Analyzer (WFA). Refer to the documentation for the 10-minute average archive data files, as well as Stone et al. (1992), for more general information on these instruments. Here, we describe the choices that were made in generating these plots. 1. Formats - These plots are available in 2 formats: GIF files for viewing with a web browser and Postscript files for high quality printed copies. The resolution of the GIF files is 776 x 600 pixels, a compromise between smaller size for network transfer and larger size for improved resolution. The Postscript files are sized to fit both 8.5x11 inch paper or A4 paper. The daily unzipped (zipped) Postscript files are typically 400-440 kB ( 130-140 KB) in size; the daily GIF files are typically 200-230 kB in size. (The 10-day and 26-day plots are similar in size.) 2. Data units - The data and the associated color bar are plotted in units of decibels, an old radio astronomer unit for describing signal to background ratio on a logarithmic scale. Specifically, Data_in_dB = 10. * log10(total power/background power) The data for electric field observations are in units of microvolts**2 Hz**(-1) as are the calculated background levels. The units for magnetic field observations (the bottom panels on the page) are nT**2 Hz**(-1). The data for the 1-day plots are comparable to the squared values of data in the URAP UFA 10-minute files. Although the ratio (total power-background power)/background power permits one to see weaker events in such plots, it is more sensitive to background determination and enhances the noise seen in the plots. Therefore, it is not used here. 3. Backgrounds - The background levels as a function of frequency for the RAR and WFA are determined from the data for the day, because they vary throughout the mission. The PFR background does not vary significantly with time, so fixed background levels are used. For each of the instruments, the backgrounds vary with the instrument mode, so separate sets of backgrounds are derived for each mode that is present. (Modes are discussed below). The PFR and WFA backgrounds also depend significantly on bit rate. For the RAR the background level selected is the lowest 3% of the data for each frequency; for the PFR and WFA, the background level selected is the lowest 10% of the data for each frequency. The higher number is chosen for the WFA because the data are substantially noisier than the RAR. It should be noted that this type of background subtraction will remove any signal at a given frequency that is constant throughout the day. An example is the quasithermal noise line ("plasma line") in the RAR data, when the density does not vary throughout the day. Note that for 10-day and 26-day plots, in particular, the background determination might result from a few hours of very low intensity data, which will cause all the other data, referenced to that background, to appear enhanced. This is an unfortunate consequence of determining the background levels from intervals of minimum data intensity. 4. Modes and other labels - Each of the instruments has several modes that affect the data display. The telemetry bit rate is also an important parameter. The key modes and the bit rate are shown on the dynamic spectrum as the thickness (or nonexistence) of a line. The RAR Hi and Lo bands are plotted in separate panels because they are commanded separately. For each band, the spin-plane and spin-axis antennas can be either summed or separate. If the RAR Hi or Lo band instrument is in summed mode, then a white line for the appropriate band is present under the RAR plot. Summed mode provides data used for 3-dimensional direction finding at the expense of a higher background level. Because the backgrounds will differ between summed and separate modes, backgrounds are calculated for both modes when they are present. Although the RAR is typically operated in a mode where measurements are made at all 76 frequencies, there are times when only a subset of the frequencies are sampled (called Measure mode). In these cases, the data plotted are interpolated in frequency to give a clearer picture of the events that might be taking place. These intervals are evident from the appearance of the data, which is smoothed in frequency; see Nov. 6, 1990, where the RAR Lo band is in Measure mode for the first 18 hours of the day. This example also shows the RAR hi band in a rarely-used, single frequency mode. If the Measure mode data occupy less than 10% of the day; they are not interpolated, because the events occurring at these times should be clear from the non-Measure mode data, and it is useful to see which frequencies are being sampled. The Jupiter flyby interval (e.g., Feb. 8, 1992) includes examples of short intervals of measure mode. The bit rate significantly affects the PFR and WFA backgrounds. If the science data bit rate is 1024 bps, it is indicated by a thick line, 512 bps is indicated by a thin line, and low ("emergency") bit rates, either 256 or 126 bps, by no line. The PFR operates in one of 3 modes - fast scan, slow scan, or fixed tune (see Stone et al., 1992). These 3 modes have different backgrounds and generate different interferences for the WFA instrument. Fast scan is shown by the white line under the PFR plot, slow scan is in progress if there is no line, and fixed tune is a single frequency mode (evident from the PFR data display), typically used in 1 hour/day intervals. The WFA instruments can sample either the electrical (E) antennas or the (B-field) search coil. For the low band of the WFA B field data (< 8 Hz), either By or Bz data are telemetered. The available parameter is shown by the white line above the B (WFA) plot (present=By, absent=Bz). 5. Interpolation - In addition to the interpolation discussed above for the RAR, the RAR data are interpolated to remove data gaps of 384 seconds or less. We interpolate the RAR data because the events observed in the RAR, such as solar type II and type III radio bursts, are mostly smoothly varying on time scales of a few minutes. Therefore, they are easier to visualize and interpret when data gaps are interpolated. For the events in the PFR and WFA data, predominantly bursty wave events, interpolation is not necessary and not performed. An exception occurs when the data telemetry rate is either 256 or 128 bps; then the WFA data are interpolated in time because they are not sampled every 128 sec. Finally, the RAR Hi band data, for which there are only 12 channels of data, are interpolated to fit a logarithmic frequency scale with 37 equivalent frequencies. 6. Interference and other issues affecting data interpretation - Each of these instruments, like all sensitive wave receivers, is affected by interference from other sources. For the RAR Hi band, an interference signal at 81 kHz is produced by the Ulysses GAS instrument. Depending on the mode in which the GAS instrument is operating, this interference can occur from 0 to 24 hours per day. If an algorithm determines that this interference is present in more than about 10% the RAR data for the day, we remove the 80 kHz data and interpolate from adjacent frequencies. The RAR Hi band also has an enhanced background at 120 kHz (source unknown). Subtraction of this enhanced background can cause artifacts in other events, like type III bursts. See Nov. 30, 1990 as an example. The RAR Lo band has an interference line at 8.75 kHz and odd harmonics caused by the Ulysses traveling wave tube amplifier (TWTA), which is part of the high gain telemetry system. In general, this signal is removed by the background subtraction, sometimes producing artifacts in weak radio events or the thermal noise spectrum at these frequencies The PFR experiences interference from the URAP Sounder; these data are removed from the plots and appear as short data gaps. The background levels of the PFR depend on bit rate, PFR mode, and the cadence of the URAP Fast Envelope Sampler (FES data not presented in these plots); these background variations can affect the appearance of events at the transition from one mode to another. The WFA data are affected by numerous interferences, of which the URAP PFR is the dominant source. WFA "backgrounds" vary significantly depending on whether the PFR is in fast or slow scan mode or fixed tune, so separate backgrounds are calculated for each of these. The URAP Sounder also causes interference; these data are removed from the plots and appear as short data gaps. Spacecraft thruster operations produce a variety of artifacts in the data; since we have no indication of these in our telemetry, they are not flagged on the plots. Examples may be seen on Feb 23, 1995 at 12:00 and on Feb. 25, 1995 at 15:00. An interesting "interference" is seen to disappear on Dec. 17, 1990; this is when the spacecraft nutation was stopped. This is best seen on the 26- day plots. To summarize, there are a variety of artifacts in the wave data that affect interpretation. These can result from corrupted telemetry values (producing bad pixels (most evident in the RAR plots, see March 23, 1993, from 6:00-14:00, or August 16, 1991, a very good example of very bad data quality), interferences (e.g., non-physical, block-like structures sometimes seen in the highest frequencies of the WFA E and B data (see March 14, 1995)), or changes of the instrument mode or the physical medium (e.g., a short interval of data with a very low signal level defines a background for the rest of the day that is not appropriate; see Nov. 4, 1990, when the Ex antenna was deployed). 7. Spacecraft location - At the lower left on the plots, 4 parameters related to the location of Ulysses at the mid-time of the plot are printed: a) the Ulysses-Sun (U-S) distance in AU, b) the heliographic latitude (Hlat_U) of Ulysses in degrees, c) the Ulysses-Sun-Earth (U-S-E) angle in degrees, and d) the Ulysses-Jupiter (U-J) distance in AU. These are among the most relevant parameters for interpreting the URAP data. Additional parameters, as well as a graphic showing the Ulysses location relative to the Sun, Earth, and Jupiter, can be found at the URAP Home Page at Goddard Space Flight Center (see below). 8. For additional information on these plots or on the URAP data, contact the PI of the URAP investigation, Dr. Robert MacDowall, at phone: 1-301-286-2608 fax: 1-301-286-1683 email: robert.macdowall@gsfc.nasa.gov. The URL for the URAP Home Page at Goddard Space Flight Center is http://urap.gsfc.nasa.gov/

3) Ulysses URAP RAR 144 Second Data in ASCII maxmize
Resource ID:spase://VWO/NumericalData/Ulysses/URAP/RAR.ASCII.PT144S
Start:1990-11-03 19:30:00 Observatory:Ulysses Cadence:144 seconds
Stop:2007-11-26 18:30:00 Instrument:Unified Radio and Plasma Waves (STO/URAP) Resource:NumericalData
This data set contains 144 second averages of the electric field intensities from the Ulysses Unified Radio and Plasma Wave Instrument Radio Astronomy Receiver (URAP/RAR). The following notes are taken from the Guide to Archiving of Ulysses URAP Data revised January 27, 2010 - version 1.3 ftp://ftp.rssd.esa.int/pub/ulysses/URAP/docs/others/archived_data_user_guide.html Appendix C: USER'S GUIDE TO RAR 144 SECOND AVERAGED DATA FILES The time period of 144 seconds was used for the averaging period because that is the basic cycling time of the instrument. The RAR continually cycles through a list of frequencies. There are 16 lists and the list currently in use is chosen by telecommand. The time period to complete the list is 144 seconds for the high band of the receiver (for telemetry bit rates of 1024 and 512 bps, the cycle time is 64 seconds for bit rates of 256 and 128 bps), after which the instrument begins with the list again. Therefore this period was chosen for the averaging period. The format of the data is indicated by the following Fortran statement which can be used to read the data: DIMENSION F(0:75) READ(1,'(I4,2I2,1X,3I2,1X,5I2,12(/6E12.4),/4E12.4)') + IYEAR, IMONTH, IDAY, IHOUR, IMINUTE, ISECOND, + LO_POL_MODE, LO_SUM_MODE, HI_POL_MODE, HI_SUM_MODE, + IBPS, F The variables are defined as follows: The date and time of the beginning of the averaging period are given in IYEAR, IMONTH, IDAY, IHOUR, IMINUTE, ISECOND. LO_POL_MODE and HI_POL_MODE are the polarization modes of the low and high receiver bands. Their values are defined as: 1: Polarization on. 2: Polarization off. 3: Polarization mode switched during the averaging interval. 4: Polarization mode was unknown (usually due to a data gap). LO_SUM_MODE and HI_SUM_MODE are the polarization modes of the low and high receiver bands. Their values are defined as: 1: Summation on. 2: Summation off. 3: Summation mode switched during the averaging interval. 4: Summation mode was unknown (usually due to a data gap). 1: Summation on. 2: Summation off. 3: Summation mode switched during the averaging interval. 4: Summation mode was unknown (usually due to a data gap). IBPS indicates the telemetry bit rate during the averaging interval. Its values are defined as: 1: 128 bps. 2: 256 bps. 3: 512 bps. 4: 1024 bps. 5: Bit rate changed during the averaging period. 6: Bit rate unknown - usually due to a data gap. F is a vector containing the average signal for the 76 frequencies of the low and high bands. Elements 0 through 63 are from the low band receiver and correspond to frequencies of 1.25+0.75*N Khz where N is the element number (0..63). The frequency channels from 64 to 75 correspond to the following frequencies: F(64): 52 KHz F(65): 63 KHz F(66): 71 KHz F(67): 100 KHz F(68): 120 KHz F(69): 148 KHz F(70): 196 KHz F(71): 272 KHz F(72): 387 KHz F(73): 540 KHz F(74): 740 KHz F(75): 940 KHz The units of the data are microvolt/Hz**.5 measured at the receiver input terminals. To convert to electric field strength the given data must be divided by the effective length of the antenna. This is complicated by the fact that the effective length depends on the antenna impedance which is affected by the plasma conditions local to the Ulysses spacecraft. The impedance will also depend on the frequency. In general, the RAR frequency channels that are well above the local electron plasma frequency are not affected by the plasma conditions and the effective length of 23 meters can be used. When the RAR is in summed, rather than separate, mode the determination of field strengths is even more difficult. Description of the Unified Radio and Plasma Wave Instrument Radio Astronomy Receiver The Radio Astronomy Receiver is divided into two parts, a low frequency receiver and a high frequency receiver. The low frequency receiver has 64 channels that cover the frequency range from 1.25 to 48.0 kHz in linear steps of 0.75 kHz. The high frequency receiver has 12 channels that cover the range from 52 kHz to 940 kHz in approximately logarithmic steps. The high frequency receiver is usually operated in what is called "measure" mode, which causes the receiver to step repeatedly through a list of frequencies that is determined by a ROM on board the spacecraft. There are 16 different lists and one of them is chosen by telecommand. The different lists emphasize different frequency ranges, so as to maximize the information received depending on the type of phenomena being studied. Some of the lists include all 12 possible frequency channels while other lists skip some of the frequencies. The list that has been used for most of the mission does include all frequecies, but there may be times when other lists have been used. At these times only a subset of the frequencies will be present. The low frequency receiver can be operated in measure mode (with its own set of lists of 8 or 16 frequencies) or in "linear sweep" mode where it steps through a contiguous set of frequencies. In linear mode, all 64 frequencies can be stepped through, or a subset of 32 frequencies can be chosen using the lower half, middle half, or upper half of the frequencies. For most of the mission, the low frequency receiver has been operated in linear mode with all 64 frequencies but there have been periods when it has operated in measure mode or in in linear mode with less than 64 frequencies. During these periods only a subset (8, 16, or 32) of the 64 possible frequencies will appear. Besides the intensity of a signal reaching the spacecraft, the RAR can also, when operated in particular modes, determine additional information about the source of the radiation, including its direction relative to the location of Ulysses, its angular size, and its polarization. This is most efficiently done with the signal from the X and Z axis antennas summed together electronically either with or without a phase shift added between the two signals. Although this additional information cannot be recovered from the averaged data, the mode does have a large effect on the background signal level, so the mode of high and low frequency receivers is given in the data as either summed (X and Z antenna combined) or separate (X antenna alone). Reference: Astron. Astrophys. Suppl. Ser., 92(2), 291-316 (1992).

4) Ulysses URAP RAR 144 Second Data maxmize
Resource ID:spase://VWO/NumericalData/Ulysses/URAP/RAR.CDF.PT144S
Start:1990-11-03 19:30:00 Observatory:Ulysses Cadence:144 seconds
Stop:2007-11-26 18:30:00 Instrument:Unified Radio and Plasma Waves (STO/URAP) Resource:NumericalData
This data set contains 144 second averages of the electric field intensities from the Unified Radio and Plasma Wave Instrument Radio Astronomy Receiver. Units are microVolt/Hz**0.5 measured at the receiver input terminals. To convert to electric field strength the given data must be divided by the effective length of the antenna. This is complicated by the fact that the effective length depends on the antenna impedance which is affected by the plasma conditions local to the Ulysses spacecraft. The impedance will also depend on the frequency. In general, the RAR frequency channels that are well above the local electron plasma frequency are not affected by the plasma conditions and the effective length of 23 meters can be used. When the RAR is in summed, rather than separate, mode the determination of field strengths is even more difficult. The time period of 144 seconds was used for the averaging period because that is the basic cycling time of the instrument. The RAR continually cycles through a list of frequencies. There are 16 lists and the list currently in use is chosen by telecommand. The time period to complete the list is 144 seconds for the high band of the receiver (for telemetry bit rates of 1024 and 512 bps, the cycle time is 64 seconds for bit rates of 256 and 128 bps), after which the instrument begins with the list again. Therefore this period was chosen for the averaging period. Notes on the Radio Astronomy Receiver from URAP User Notes http://helio.esa.int/ulysses/archive/urap_un.html The Radio Astronomy Receiver is divided into two parts, a low frequency receiver and a high frequency receiver. The low frequency receiver has 64 channels that cover the frequency range from 1.25 to 48.0 kHz in linear steps of 0.75 kHz. The high frequency receiver has 12 channels that cover the range from 52 kHz to 940 kHz in approximately logarithmic steps. The high frequency receiver is usually operated in what is called "measure" mode, which causes the receiver to step repeatedly through a list of frequencies that is determined by a ROM on board the spacecraft. There are 16 different lists and one of them is chosen by telecommand. The different lists emphasize different frequency ranges, so as to maximize the information received depending on the type of phenomena being studied. Some of the lists include all 12 possible frequency channels while other lists skip some of the frequencies. The list that has been used for most of the mission does include all frequecies, but there may be times when other lists have been used. At these times only a subset of the frequencies will be present. The low frequency receiver can be operated in measure mode (with its own set of lists of 8 or 16 frequencies) or in "linear sweep" mode where it steps through a contiguous set of frequencies. In linear mode, all 64 frequencies can be stepped through, or a subset of 32 frequencies can be chosen using the lower half, middle half, or upper half of the frequencies. For most of the mission, the low frequency receiver has been operated in linear mode with all 64 frequencies but there have been periods when it has operated in measure mode or in in linear mode with less than 64 frequencies. During these periods only a subset (8, 16, or 32) of the 64 possible frequencies will appear. Besides the intensity of a signal reaching the spacecraft, the RAR can also, when operated in particular modes, determine additional information about the source of the radiation, including its direction relative to the location of Ulysses, its angular size, and its polarization. This is most efficiently done with the signal from the X and Z axis antennas summed together electronically either with or without a phase shift added between the two signals. Although this additional information cannot be recovered from the averaged data, the mode does have a large effect on the background signal level, so the mode of high and low frequency receivers is given in the data as either summed (X and Z antenna combined) or separate (X antenna alone). Reference: Astron. Astrophys. Suppl. Ser., 92(2), 291-316 (1992).

Showing 1 - 4