| DATA_SET_DESCRIPTION |
Data Set Overview
=================
This data set contains raw Radio Occultation (ROCC) Original Data
Records data from the Ulysses (ULY) Solar Corona Experiment (SCE)
obtained during the ULY Jupiter flyby. The data target the Io
Plasma Torus (IPT) and cover the period 1992-02-03 11:20 to
1992-02-09 20:46.
The data set includes 41 NASA Deep Space Network (DSN) Original
Data Record files (ODR), and documentation. These data are
obtained from the Radio Science Support group at JPL. They consist
of time-ordered, high-time resolution Doppler data from special
radio science receivers (so-called 'open loop' data).
The radio downlinks from Ulysses were monitored during the
passage of the spacecraft through the IPT shortly after closest
approach to Jupiter. The electron content of the Io torus was
derived from the dispersive phase shift of the S-band (2.3 GHz)
signal with respect to the X-band (8.4 GHz) signal. Corrections
were applied for non-Jovian contributions to the change in
electron content arising from the interplanetary medium and the
terrestrial ionosphere. Ulysses' North-to-South encounter
trajectory was well suited for investigating the global structure
of the Jovian plasma environment near Io's orbit, especially its
latitudinal extent and azimuthal variations. (IPT investigation
description adapted from [BIRDETAL1993]. For more information
please refer to the complete paper.)
Parameters
==========
Open loop data records (ODRs) contain 8-bit samples of receiver
output. Each block of (nominally) 500 data samples from each of
four receivers (or channels) is accompanied a 166 byte header.
Each ODR is accompanied by a full PDS label which describes both
the content and format of the file at the bit level. Header
information includes:
Date and time of first data sample
Sample rate and channel assignments
Receiver local oscillator (POCA) frequency
Attenuator settings
RMS voltages at several stages in the receiving chain
Channel assignments are as follows:
Channel 1 X-RCP (X-band right circularly polarized)
Channel 2 S-RCP (S-band right circularly polarized)
Channel 3 X-LCP (X-band left circularly polarized)
Channel 4 S-LCP (S-band left circularly polarized)
The ODR is described by a Software Interface Specification (SIS),
included as RSC1110A.ASC in the DOCUMENT/RSC1110A directory of
this volume.
Processing
==========
Open loop data (ODRs) are not edited or otherwise processed before
being incorporated into this archive. A 32-byte label at the
beginning of each ODR tape is not included in the data file; it
gives the software version of the data taking equipment and is
saved instead in the PDS label that accompanies the data file.
Data
====
ODRs were generated at stations of the NASA Deep Space Network
(DSN) and were distributed on 6250 bpi tape. Those tapes have been
copied to disk files, defined as PDS TABLE Objects, and archived
on this DVD-WO volume. Ancillary data to support analysis are
provided in the GEOMETRY, and DOCUMENT directories.
A nominal ODR contains 36000 records, each record having 166 bytes
of header data and 2000 bytes of 8-bit sample data.
On this volume ODR files have names of the form 'ydddhhmm.ODR'
where 'y' gives the least significant digit of the year, 'ddd' is
the 3-digit day-of-year, 'hh' is the 2-digit hour, and 'mm' is the
2-digit minute on which data acquisition for the file began.
Each ODR data file is accompanied by a full PDS detached label
with name 'ydddhhmm.LBL' which completely describes the contents
of the ODR file. The format and contents are also described in
RSC1110A.ASC in the DOCUMENT/RSC1110A directory of this archival
volume.
Ancillary Data
==============
For each ODR, there is a set of ancillary files needed for
analysis. These are stored in the DOCUMENT and GEOMETRY
directories, as appropriate.
Observing Geometry
------------------
A NAIF (PDS Navigation and Ancillary Information) 'transfer'
format SPK files is provided for the period 1992-01-05 to
1995-10-31. This file contains the positions of Ulysses,
Jupiter, Earth, the Sun, and Jupiter's four Galilean satellites
(Io, Europa, Ganymede, and Callisto) in data modules that can be
used readily with NAIF Toolkit software. This 'transfer' format
SPK file (ULY92106.XSP) is located in the GEOMETRY directory.
The XSP file is accompanied by a detached PDS label
(ULY92106.LBL) which describes some of the SPK file's
characteristics.
Before using 'transfer' NAIF files, the user should convert
ASCII carriage-return line-feed delimiters on each record to the
default delimiter for text files on the local system, then use
the NAIF utility SPACIT to convert the archival file to local
binary.
An overview of the SPICE data system can be found in SPICE.TXT
located in the DOCUMENT directory of this volume.
For additional information on acquiring, installing, and using
SPICE data or software please contact the PDS NAIF node:
Address: Jet Propulsion Laboratory
Mail Stop 301-125L
Pasadena, California 91109-8099
Phone: (818) 354-3869
E-mail: Charles.Acton@jpl.nasa.gov
or
pds_operator@naif.jpl.nasa.gov
Documentation
-------------
A copy of a document [RSC-11-10A] describing the format of the
Ulysses ODR data contained on this volume is provided in the
DOCUMENT/RSC1110A directory.
Coordinate System
=================
SPK ephemeris files and quaternion files were produced for the
J2000 inertial reference frame. SPICE reader routines may be used
to convert these to other coordinate systems.
Other data types are not dependent on definition of a coordinate
system.
Software
========
Software for parsing, reducing, and analyzing these data has been
developed at Stanford University, the Jet Propulsion Laboratory,
and other institutions. Because parsing must be done at the bit
level, adaptation of the software to other platforms is not always
easy. No software has been prepared for general distribution, and
none is included with this archive. Users should refer to the PDS
labels and Software Interface Specifications
(/DOCUMENT/RSC1110A/RSC1110A.ASC) for detailed information on file
formats before writing their own software.
Media/Format
============
This archival data set is written on DVD-R media using a Pioneer
DVR-A03 recorder (DVD-R for General, 650 nm wavelength). The DVD-R
volume conforms to ISO 9660 standards.
|
| CONFIDENCE_LEVEL_NOTE |
Confidence Level Overview
=========================
The ODR data files have been tested by being read, a histogram
computed of sample values, time-averaged power spectra derived
from the samples, and one-second averages generated of sample
power. Data quality concerns discovered in this process are listed
the 'Data Coverage and Quality' section below.
Review
======
Prior to creation of the final version of the archival data set,
the archive was distributed to both PDS and non-PDS personnel,
including the PDS Radio Science advisor, for preliminary review.
Data Coverage and Quality
=========================
The following table describes data file size and coverage:
File bytes start time stop time
------------ -------- ---------------- ----------------
20341120.ODR 21768300 1992-02-03 11:20 1992-02-03 12:43
20341246.ODR 77976000 1992-02-03 12:46 1992-02-03 17:46
20341746.ODR 50285856 1992-02-03 17:46 1992-02-03 21:00
20351118.ODR 30064080 1992-02-04 11:18 1992-02-04 13:14
20351314.ODR 77976000 1992-02-04 13:14 1992-02-04 18:14
20351814.ODR 40161972 1992-02-04 18:14 1992-02-04 20:49
20371245.ODR 23475108 1992-02-06 12:45 1992-02-06 14:15
20371415.ODR 77976000 1992-02-06 14:15 1992-02-06 19:15
20371915.ODR 23184864 1992-02-06 19:15 1992-02-06 20:45
20372015.ODR 21755304 1992-02-06 20:15 1992-02-06 21:38
20372139.ODR 77976000 1992-02-06 21:39 1992-02-07 02:39
20380239.ODR 32871216 1992-02-07 02:39 1992-02-07 04:45
20380350.ODR 4555098 1992-02-07 03:50 1992-02-04 04:33
20380407.ODR 17228364 1992-02-07 04:07 1992-02-07 05:14
20380523.ODR 73646166 1992-02-07 05:23 1992-02-07 10:06
20381007.ODR 29362296 1992-02-07 10:07 1992-02-07 11:59
20381119.ODR 26043984 1992-02-07 11:19 1992-02-07 12:59
20381259.ODR 77976000 1992-02-07 12:59 1992-02-07 17:59
20381759.ODR 42791496 1992-02-07 17:59 1992-02-07 20:44
20382011.ODR 23020248 1992-02-07 20:11 1992-02-07 21:39
20382140.ODR 77976000 1992-02-07 21:40 1992-02-08 02:40
20390240.ODR 50931324 1992-02-08 02:40 1992-02-08 05:56
20390350.ODR 29581062 1992-02-08 03:50 1992-02-08 05:44
20390544.ODR 77976000 1992-02-08 05:44 1992-02-08 10:44
20390556.ODR 539334 1992-02-08 05:56 1992-02-08 05:58
20390602.ODR 29379624 1992-02-08 06:02 1992-02-08 07:55
20391044.ODR 13206102 1992-02-08 10:44 1992-02-08 11:35
20391116.ODR 35990256 1992-02-08 11:16 1992-02-08 13:34
20391135.ODR 31183902 1992-02-08 11:35 1992-02-08 13:35
20391335.ODR 77976000 1992-02-08 13:35 1992-02-08 18:35
20391336.ODR 18246384 1992-02-08 13:36 1992-02-08 14:46
20391835.ODR 34950576 1992-02-08 18:35 1992-02-08 20:49
20392020.ODR 21530040 1992-02-08 20:20 1992-02-08 21:43
20392143.ODR 77976000 1992-02-08 21:43 1992-02-09 02:43
20400243.ODR 77976000 1992-02-09 02:43 1992-02-09 07:43
20400416.ODR 15001716 1992-02-09 04:16 1992-02-09 05:14
20400743.ODR 3210012 1992-02-09 07:43 1992-02-09 07:56
20401015.ODR 3853314 1992-02-09 10:15 1992-02-09 10:29
20401130.ODR 25379022 1992-02-09 11:30 1992-02-09 13:07
20401308.ODR 77976000 1992-02-09 13:08 1992-02-09 18:08
20401808.ODR 40915740 1992-02-09 18:08 1992-02-09 20:46
General data quality issues:
Ulysses' S-band downlink is elliptically polarized with an axial
ratio of approximately 2:1. While, with a 2:1 axial ratio, a
difference of 10 dB might be expected between the signal-to-noise
ratios (SNR) of the S-band LCP and RCP, the actual difference is
around 15 dB. This deviation from the expected difference may be
attributed to the fact that the value of 2:1 used for the axial
ratio is only approximate.
There appears to be a broad noise apron around the carrier
(approx. 10 dB and extending to +/-100 Hz) each time a signal is
present.
Specific data quality issues:
The S-band downlink was started 1992-02-05 19:44 (DOY 36). As a
result there is no signal on channels 2 and 4 on days 34 and 35.
20341246.ODR - A/D converter saturated on ch. 3
20341746.ODR - A/D converter saturated on ch. 3
20351314.ODR - variation in sample power large on ch. 3 (+/-3
dB about its mean)
20380350.ODR - histogram of sample values on ch. 1 suggest A/D
converter not working; unable to compute spectra
or sample power vs. time for any channel
20380407.ODR - abnormal histogram of sample values on ch. 1
20390240.ODR - variation in sample power large on ch. 3
(+/-2.5 dB about its mean)
20390350.ODR - abnormal histogram of sample values on ch. 1
20390544.ODR - abnormal histogram of sample values on ch. 1;
variation in sample power large on ch. 3 (+/-2
dB about its mean)
20390556.ODR - only 124 sec. of data; no carrier on any channel
20390602.ODR - receiver tuning predicts not good enough: carrier
signal drifts out of passband on ch. 1 and 3
20392020.ODR - A/D converter on ch. 3 slightly saturated
20400243.ODR - receiver tuning predicts not good enough: carrier
signal drifts out of passband on ch. 1 and 3
20400416.ODR - abnormal histogram of sample values on ch. 1
20400743.ODR - receiver tuning predicts not good enough: carrier
signal near edge of passband on ch. 1 and 3 for
first half of file, then drifts outside for
second half
20401015.ODR - abnormal histogram of sample values on ch. 1
20401808.ODR - no signal during second half of file on ch. 2 and
4
Limitations
===========
See 'Data Coverage and Quality' section above.
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