| URAP |
To reduce the size of the files produced, the UDS files contain 25 frequency channels for the RAR - the upper 12 frequencies of the high receiver, and 13 lower frequencies which are aggregates of the low frequency channels so that they appear in approximately the same logarithmic steps as the high frequency receiver. Since the low frequency receiver steps are linear, there are different numbers of frequency channels that are combined to produce the UDS data.
Following is a table giving the approximate center frequency of each UDS channel and the RAR frequencies that were combined to produce it.
UDS center RAR frequency
channel frequency channels
(kHz) (kHz)
------------------------------------------
1 1.25 1.25 Low receiver
2 2.00 2.00
3 2.75 2.75
4 3.50 3.50
5 4.25 4.25
6 5.75 5.00 - 6.5
7 8.00 7.25 - 8.75
8 11.0 9.50 - 12.5
9 14.75 13.25 - 16.25
10 19.25 17.00 - 21.50
11 24.50 22.25 - 26.75
12 31.25 27.50 - 35.00
13 42.50 35.75 - 48.50
14 52.0 52.0 High receiver
15 63.0 63.0
16 81.0 81.0
17 100.0 100.0
18 120.0 120.0
19 148.0 148.0
20 196.0 196.0
21 272.0 272.0
22 387.0 387.0
23 540.0 540.0
24 740.0 740.0
25 940.0 940.0
Two files are produced for each day: they contain averages and peak values for 10 minute periods that start at 00:00:00 and end at 24:00:00. The time specified in the file is the beginning of each time period.
The data are computed as follows: For all RAR data that falls within the 10 minute period being considered the average and peak values are found for each of the 76 channels. Next the channels are combined to produce the 25 UDS channels: the average of the combined channels yields the UDS averages and the peak of the combined channels yields the UDS peak value.
The names of the files are (following the UDS convention):
UURARARAyyddd.ULY : Average data
UURARARPyyddd.ULY : Peak data
where:
yy = Last two digits of year.
ddd = Day of year (001..366).
The files are Ascii and contain one line for each time period
(even if there are no valid data for a time period) so they
contain 144 lines each. The format of the data is indicated by
the following Fortran read statement which can be used to read
the files:
DIMENSION F(25)
READ(1,100) IYEAR,IDOY,IHOUR,IMIN,ISEC,
+MODE_HI,MODE_LO,IBPS,F
100 FORMAT(I4,I4,3I3,3X,3I1,1P25E10.2)
where:
IYEAR: year
IDOY : day of year (Jan 1 = 001)
IHOUR: hour, UT
IMIN : minute, UT
ISEC : second, UT IYEAR .. ISEC is the beginning of the
averaging period.
MODE_HI: mode of the high receiver:
1: Receiver in summed mode (X and Z antenna combined).
2: Receiver in separate mode(only X antenna).
3: Receiver switched mode during averaging period.
4: Receiver mode unknown.
MODE_LO: mode of the low receiver
1: Receiver in summed mode (X and Z antenna combined).
2: Receiver in separate mode (only X antenna).
3: Receiver switched mode during averaging period.
4: Receiver mode unknown.
IBPS: telemetry bits-per-second
1: 128 bps.
2: 256 bps.
3: 512 bps.
4: 1024 bps.
5: Bit rate changed during averaging period.
6: Bit rate unknown.
F: frequency data - channels 1..25 as defined above.
Invalid or missing data are assigned the value -99.0.
Units: Units 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.
Time resolution: 10 minutes.
To reduce the size of the UDS files only 16 frequency channels are given which represent the combination of every 2 adjacent channels.
The UDS average data files are computed by averaging the Ex-average data values all data that falls in each 10 minute period for each of the 32 channels. Then adjacent channels are averaged together to yield the 16 channels present in the UDS files.
The UDS peak data files are computed by finding the the peak value of the Ex-peak data that falls in the 10 minute period. Then the peak of adjacent channels is found to yield the 16 channels present in the UDS files.
Because of the limited usefulness of fixed-frequency data when averaged, it has been ignored when creating the UDS files so these 1 hour intervals of fixed-frequency will be replaced by the "bad data" value of -99.
File names (following UDS convention):
UURAPFRAyyddd.ULY -> Average data
UURAPFRPyyddd.ULY -> Peak data
yy: Last two digits of year.
ddd: Day of year (001..366).
The files are Ascii and contain one line for each time period (even if there are no valid data for a time period) so they contain 144 lines each. The format of the data is indicated by the following Fortran read statement which can be used to read the files:
DIMENSION F(16)
READ(1,100) IYEAR,IDOY,IHOUR,IMIN,ISEC,MODE,IBPS,F
100 FORMAT(I4,I4,3I3,4X,2I1,1P16E10.2)
These variables are defined as follows:
IYEAR: year
IDOY: day of year
IHOUR: hour
IMIN: minute
ISEC: second
MODE: PFR scan mode:
1: Fast mode.
2: Slow mode.
3: Fixed frequency mode. This value should not occur as
fixed frequency data is removed from the UDS data.
4: The mode switched from fast to slow or slow to fast
during the averaging interval.
5: Unknown mode. This value occurs if there was no valid
data during the averaging interval. This could be due
to a data gap or bad data. Data acquired while the PFR
is in fixed tune mode is ignored so this value for the
MODE will also occur if the PFR was in fixed tune mode
during the entire averaging interval.
IBPS: Telemetry bit rate:
1: 128 bps.
2: 256 bps.
3: 512 bps.
4: 1024 bps.
5: Bit rate changed during averaging period.
6: Bit rate unknown.
F: Contains the PFR data (either average or peak values,
depending on the file) of the 16 frequency channels. The
frequencies given below are the average of the two adjacent
frequencies that are combined.
F(1): 0.61 kHz
F(2): 0.80 kHz
F(3): 1.04 kHz
F(4): 1.35 kHz
F(5): 1.77 kHz
F(6): 2.30 kHz
F(7): 3.01 kHz
F(8): 3.92 kHz
F(9): 5.11 kHz
F(10): 6.67 kHz
F(11): 8.70 kHz
F(12): 11.34 kHz
F(13): 14.79 kHz
F(14): 19.30 kHz
F(15): 25.16 kHz
F(16): 32.82 kHz
NOTES:
These data are electric field intensities detected by the Plasma Frequency Receiver (PFR) on the X antenna of the URAP instrument.
Units: Units 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. Although, a single number is not accurate for the effective antenna length, the monopole length of 35 meters is a useful approximation.
Time resolution: 10 minutes
Fill value for bad or missing data is -99.0
Four UDS files are produced per day for the WFA data. Two of the files contain average and peak data for the Ex signals and two files contain average and peak data for magnetic field data. The high band channels (upper 12 frequencies) always contain By. The low band channels (lower 10 frequencies) contain either By or Bz depending on the mode of the instrument. A flag specifying the mode is provided for each time interval.
The lowest two frequencies of the WFA are derived in a different manner so they have been left out of the UDS data. This leaves 10 frequencies from the low band and 12 frequencies from the high band. The frequencies are given below.
The peak data provided by the WFA high band frequently do not exceed the threshold background so the average values have been used in all cases.
The files of 10 minute averaged data were computed by, for all data falling within the 10 minute periods, finding the average values for each frequency.
Similiarly, the files of peak data were computed by, for all data falling within the 10 minute periods, finding the maximum value for each frequency.
The WFA data is affected by interference from other instruments. In particular, interference from the PFR occurs and is dependent on the PFR scan mode. For this reason a flag indicating the PFR mode is provided in the WFA files.
UURAWFEAyyddd.ULY -> Average data
UURAWFEPyyddd.ULY -> Peak data
yy: Last two digits of year.
ddd: Day of year (1..366).
The files are Ascii and contain one line for each time period (even if there are no valid data for a time period) so they contain 144 lines each. The format of the data is indicated by the following Fortran read statement (which can be used to read the files):
DIMENSION F(22)
READ(1,100) IYEAR,IDOY,IHOUR,IMIN,ISEC,IPFRMODE,IBPS,F
100 FORMAT(I4,I4,3I3,2X,2I1,1P22E10.2)
The variables are defined as follows:
IYEAR: year
IDOY: day of year
IHOUR: hour
IMIN: minute
ISEC: second
IPFRMODE: Indicates the scan mode of the PFR instrument.
1: Fast scan mode.
2: Slow scan mode.
3: Fixed-frequency mode.
4: The mode switched during the averaging interval.
5: The mode could not be determined.
IBPS: Telemetry bit rate:
1: 128 bps.
2: 256 bps.
3: 512 bps.
4: 1024 bps.
5: Bit rate changed during averaging period.
6: Bit rate unknown.
F: Contains the data for Ex (either average or peak values,
depending on the file) of the 22 frequency channels. The
frequencies are:
F(1): 0.22 Hz
F(2): 0.33 Hz
F(3): 0.44 Hz
F(4): 0.66 Hz
F(5): 0.88 Hz
F(6): 1.33 Hz
F(7): 1.77 Hz
F(8): 2.66 Hz
F(9): 3.55 Hz
F(10): 5.33 Hz
F(11): 9.00 Hz
F(12): 14.00 Hz
F(13): 19.00 Hz
F(14): 28.00 Hz
F(15): 37.00 Hz
F(16): 56.00 Hz
F(17): 75.00 Hz
F(18): 112.00 Hz
F(19): 149.00 Hz
F(20): 224.00 Hz
F(21): 299.00 Hz
F(22): 448.00 Hz
These data are electric field intensities detected by the Waveform Analyzer (WFA) on the X antenna of the URAP instrument.
Units: Units 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. Although, a single number is not accurate for the effective antenna length, the monopole length of 35 meters is a useful approximation.
Time resolution: 10 minutes
Fill value for bad or missing data is -99.0
The names of the files are (following the UDS convention):
UURAWFBAyyddd.ULY -> Averaged data
UURAWFBPyyddd.ULY -> Peak data
yy: Last two digits of year.
ddd: Day of year (1..366).
The files are Ascii and contain one line for each time period (even if there are no valid data for a time period) so they contain 144 lines each. The format of the data is indicated by the following Fortran read statement (which can be used to read the files):
DIMENSION F(22)
READ(1,100) IYEAR,IDOY,IHOUR,IMIN,ISEC,
+IPFRMODE,IANTENNA,IBPS,F
100 FORMAT(I4,I4,3I3,2X,3I1,1P22E10.2)
The variables are defined as follows
IYEAR: year
IDOY: day of year
IHOUR: hour
IMIN: minute
ISEC: second
IANTENNA: Antenna used for low band (0.22 to 5.33 Hz). The high
band (9.8 Hz and above) is always By.
1: By
2: Bz
3: Antenna switched during the averaging interval.
4: Antenna unknown.
IPFRMODE: Indicates the scan mode of the PFR instrument.
1: Fast scan mode.
2: Slow scan mode.
3: Fixed-frequency mode.
4: The mode switched during the averaging interval.
5: The mode could not be determined.
IBPS: Telemetry bit rate:
1: 128 bps.
2: 256 bps.
3: 512 bps.
4: 1024 bps.
5: Bit rate changed during averaging period.
6: Bit rate unknown.
F: Contains the data for By or Bz (either average or peak
values, depending on the file) of the 22 frequency channels.
The frequencies are:
F(1): 0.22 Hz
F(2): 0.33 Hz
F(3): 0.44 Hz
F(4): 0.66 Hz
F(5): 0.88 Hz
F(6): 1.33 Hz
F(7): 1.77 Hz
F(8): 2.66 Hz
F(9): 3.55 Hz
F(10): 5.33 Hz
F(11): 9.00 Hz
F(12): 14.00 Hz
F(13): 19.00 Hz
F(14): 28.00 Hz
F(15): 37.00 Hz
F(16): 56.00 Hz
F(17): 75.00 Hz
F(18): 112.00 Hz
F(19): 149.00 Hz
F(20): 224.00 Hz
F(21): 299.00 Hz
F(22): 448.00 Hz
These data are magnetic field intensities detected by the
Waveform Analyzer (WFA) on the URAP instrument.
Units: 10**-15 Tesla/Hz**0.5
Time resolution: 10 minutes
Fill value for bad or missing data is -99.0
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Updated 2005-10-17