README.TXT describes the contents of this volume.

                CLUSTER WBD LEVEL1 Data Distribution

============================================================================
INTRODUCTION
============================================================================

This volume contains the Cluster Wideband Receiver (WBD) time series data.
Except for a limited amount of burst mode (BM-2) data, this data set is
derived entirely from real time telemetry (normal science mode TDA-8) received
by the Deep Space Network (DSN) stations and forwarded to Iowa for processing.
These burst mode and real time raw data are the only sources of Cluster WBD
data.  The files in this data set are called LEVEL1 files (referring to the
LEVEL1 processing that the raw data have undergone:  When the data files are
received from DSN, the WBD team at Iowa checks these raw data files for
problems, determines the time tags associated with each data record [see
TIMETAGS.TXT], unpacks all status parameters, and writes the LEVEL1 files).
LEVEL1 files have the following naming convention:

       yymmddtt.ivs where:

       yy = last 2 digits of the year
       mm = Month
       dd = Day of month
       tt = The files are divided into ten minute periods and tt is the
            ten minute period in HEXADECIMAL.

	    Example:

	    tt = 20 (hex) = 32 (base 10)
	    32*10 minutes = 320 minutes of day
	    320/60 = 5.33333 Hours.  0.33333*60 = 20 minutes
	    The start time of the file will be 05:20:00.
	    The file will contain data with  05:20 <= time < 05:30.

            Or going the other way,

            Want to find the file containing s/c 4 data at 13:47:00 on
              23 Nov. 2003
            (13*60 + 47)/10 = 82.7 minutes (base 10)
            Truncate to integer, 82 (base 10), and convert to hex, 52 (hex)
            The file will be 03112352.8C4 (assuming a version 'C' file).

       i =   Instrument number (6-9)
       v =   Version number (Should be B for burst mode data or C-Z for
             DSN data.  Later letters = more recent versions, with version A
             files already being obsolete.)
       s =   Spacecraft number (1-4)

       For version 'C' files, the resulting extensions are:  S/c 1 = 9C1,
       s/c 2 = 6C2, s/c 3 = 7C3, s/c 4 = 8C4.

These files are found under the directory [DATA] which is subdivided into
directories by date and spacecraft.

The DVD volume naming convention, except for Burst Mode, is as follows:

      WBD_yyyymmdd_dd_v, where:

      yyyy = Year
      mm   = Month
      first dd = Day of month of first day of data contained on this DVD
      last dd  = Day of month of last day of data contained on this DVD
      v = version of the DVD (A-Z) (Note, these versions are independent of
          those contained in the file names described above.)

For Burst Mode, the DVD volume naming convention is as follows:

      WBD_yyyymmdd_dd_v_BURST, where:

      yyyy = Year
      mm   = Month
      first dd = Day of month of first day of data contained on this DVD
      last dd  = Day of month of last day of data contained on this DVD
      v = version of the DVD (A-Z) (Note, these versions are independent of
          those contained in the file names described above.)

============================================================================
IMPORTANT INFORMATION ABOUT THIS VOLUME
============================================================================

This volume contains Cluster WBD time series data.  All users are encouraged
to verify the correctness of the data (by contacting any member of the WBD
science team--see the CONTACTS section at the end of this document) prior to
submitting any publication or other work based on these data.  Users are
encouraged to acknowledge the Principal Investigator of the data used in
analysis in all publications.

All data files are recorded in the [DATA] branch of the root directory,
which is further divided into subdirectories by date and spacecraft number.
The format of the WBD data files on this DVD is described in the text file
WBFORMAT.TXT.

============================================================================
TIME STAMPS AND RELATIONSHIP TO OTHER CLUSTER DATA SETS
============================================================================

The WBD time of measurement time stamps known as UT_OBT are derived using the
On Board Time (OBT) counter and the ESA-supplied time calibration files
(see TIMETAGS.TXT).  These derived times stamps should correlate with the
time stamps provided to the other Cluster instruments by ESOC (European Space
Operations Centre).  The WBD UT_OBT time stamps are found in bytes 1232-1247,
byte 1275 and byte 94 of the LEVEL1 record (see WBFORMAT.TXT).

There are also alternative time stamps available in the LEVEL1 files.  These
time stamps are derived using DSN's Earth Received Time as a basis, as opposed
to the On Board Time counter.  These alternative time stamps are referred to
as UT_GRT, and can be found in bytes 1224-1231 of the LEVEL1 file (see
WBFORMAT.TXT).  Please see the TIMETAGS.TXT file for details on these
alternative times, and for indications of when it might be appropriate to use
them.

============================================================================
MULTIPLE SPACECRAFT OPERATIONS
============================================================================

For any given interval, simultaneous WBD data may be available for one to four
spacecraft.  There are certain operations however, designated as Multiple
Spacecraft Operations (MSOs), when special procedures were used at DSN while
taking three- or four-spacecraft data.  For a 10-minute period, all of the DSN
antennas involved in the operation would track and receive data only from a
single spacecraft.  These calibration (CAL) data can be used, under certain
circumstances, to further increase the accuracy of the UT_GRT time stamps
by analyzing time stamp differences for any one data frame between any
two antennas.  These difference should be nearly repeatable over time
because they are associated with the delay of the signal from the reception
antennas to the individual telemetry recording stations.  Applying these
differences to the appropriate antennas when tracking other Cluster
spacecraft thus provides greater relative timing accuracy across the Cluster
spacecraft as opposed to absolute time stamp accuracy.

The data for these MSO CAL runs are in separate directories on the DVD (see
DVD CONTENTS AND STRUCTURE section below).  Please contact the PI for a
suggested software routine to carry out the timing analysis of the MSO CAL
data.

============================================================================
SPACECRAFT NAMING CONVENTIONS
============================================================================

Note that the WBD instrument number that is in one of the status bytes
(byte 1271 of LEVEL1 file--see WBFORMAT.TXT) has a value ranging from 4 to 7
and therefore must be mapped to the ESA spacecraft numbering system using the
following table.

|-    WBD ID'S    -|
Instr.  Instr. DSN | S/C Old    Name   Color    Style   Symbol
Status   #      #  | Id  Name
Value              |
4        6     185 | 2   FM6    Salsa  Red      _ _     Plus or Diamond
5        7     194 | 3   FM7    Samba  Green    . .     asterisk or Circle
6        8     196 | 4   FM8    Tango  Magenta  _...    Star  or Triangle
7        9     183 | 1   FM5    Rumba  Black    ____    Cross or Square
^                  | ^
|<-- WBD Values    | |<-- ESA Values

============================================================================
FILE FORMATS
============================================================================

The data files on this DVD are in binary format (1-, 2-, and 4-byte unsigned
integers) and contain no floating point values.  Multi-byte items are
"most significant byte first" or "big endian".  The only fields to which
this applies will be the multi-byte fields, most of which hold time values.
See WBFORMAT.TXT, which gives a detailed description of the format of the
data files.

Burst mode data from ESA processing have been placed into the same LEVEL1
format as the DSN data.  There are some differences, primarily in that the
burst mode records do not have any of the Ground Received time fields or
any of the DSN-specific elements contained within the Standard Formatted
Data Unit (SFDU) header area of the data record.  (For details see the
format document, WBFORMAT.TXT.)

Most files other than the LEVEL1 files on this DVD are ASCII text whose
lines are terminated by a carriage return and line feed.

============================================================================
ERRATA
============================================================================

The file ERRATA.TXT contains a list of deficiencies or caveats associated with
this and previous DVD's, as known at the time this DVD was produced.  For data
interpretation issues, please see the Cluster Interpretation Issues web page,
available at:

  http://www-pw.physics.uiowa.edu/cluster/interpretation_issues/

and also at the Cluster Active Archive (http://caa.estec.esa.int/caa/).
Please check these files before contacting the PI about data problems or
interpretation issues.

============================================================================
SOFTWARE
============================================================================

There is a set of example software routines that read the LEVEL1 files
contained on this DVD.  The code should be compatible with most common
architectures supporting an ANSI standard C compiler.

There are also routines to correct known problems found in the data
(see ERRATA.TXT) and routines to calibrate the electric and magnetic field
wave data in the time domain for each instrument.

The current set of programs can be found in the directory [SOFTWARE] under
subdirectories [EXAMPLES], [CLU2_FIX], and [CAL].

Updates, corrections, and additions to this software may be found online at

  http://www-pw.physics.uiowa.edu/cluster/dvd/SOFTWARE/

============================================================================
DVD CONTENTS AND STRUCTURE
============================================================================

Below is a tree diagram of this DVD, followed by a description of the
directory function and key files in each directory.

 [THIS VOLUME]
   |
   |- README.TXT        This file.
   |
   |- [DATA]            Contains all data in the subdirectories.
   |    |
   |    |- [yyyy_mm_dd] for each day for which data are available,
   |    |    |          where yyyy is the year, mm is the month, and dd is
   |    |    |          the day of month.
   |    |    |
   |    |    |- [CLUSTERn] for the appropriate spacecraft (n = 1, 2, 3, 4).
   |    |    |    |
   |    |    |    |- yymmddtt.ivs These are the level 1 data files, one
   |    |    |    |     for each available 10-minute interval.  The file
   |    |    |    |     naming convention is described above.
   |    |    |    |
   |    |    |    |- [CAL] Contains ground time calibration files
   |    |    |         |   (period = 10 minutes).  This directory will
   |    |    |         |   only be present when there is a
   |    |    |         |   multi-spacecraft operation (MSO).
   |    |    |         |
   |    |    |         |- [DSS_n1] Calibration files for first station.
   |    |    |         |- [DSS_n2] Calibration files for second station.
   |    |    |         |- [DSS_n3] Calibration files for third station.
   |    |    |         |- [DSS_n4] Calibration files for fourth station.
   |
   |- ERRATA.TXT        Contains a list of known problems
   |                    with WBD data found on this DVD.
   |
   |- INSTDESC.TXT      A description of the WBD instrument in
   |                    ASCII text format.
   |
   |- MD5CRLF.TXT       Lists all files on this disk along with their MD5
   |                    checksum.  This version is formatted with ASCII
   |                    cr/lf line termination for Microsoft platforms.
   |                    Use "md5sum -c MD5CRLF.TXT" to verify each file.
   |                    See http://www.gnu.org/software/coreutils/
   |
   |- MD5LF.TXT         Lists all files on this disk along with their MD5
   |                    checksum.  This version is formatted with ASCII
   |                    lf line termination for UNIX platforms.
   |                    Use "md5sum -c MD5LF.TXT" to verify each file.
   |
   |- [SOFTWARE]        Contains example software.  Individual files for
   |    |               these directories are not described here.
   |    |
   |    |- [CAL]        Contains C source code to calibrate the
   |    |               data in the time domain.
   |    |
   |    |- [CLU2_FIX]   Contains C source code to fix a known
   |    |               problem with Cluster 2 data.
   |    |
   |    |- [EXAMPLES]   Contains example programs for reading LEVEL1 data
   |                    files, including sample input and output files.
   |
   |- TIMETAGS.TXT      A description of the time stamps contained in the
   |                    WBD level 1 data files.
   |
   |- WBFORMAT.TXT      Contains the description of the format
                        of the LEVEL1 data files found on this volume.

============================================================================
DRIVER AND HARDWARE INFORMATION
============================================================================

This disk has been formatted according to a combination of ISO 9660
level 2, Rock Ridge (UNIX), Joliet (Microsoft), and UDF standards.  It
has been recorded on DVD-R media and should be readable on all major
computing platforms hosting DVD readers.

============================================================================
UPDATES
============================================================================

Non-critical updates to this file and other general text documents provided
on this volume may be found online at:

  http://www-pw.physics.uiowa.edu/cluster/dvd/

Be sure to check the current ERRATA.TXT file for errors reported for this
particular volume.  If the errors are sufficient to warrant the release of
a new version of this volume (corrected level 1 data, for example), then a
note will be made in the current online ERRATA.TXT.

============================================================================
CONTACTS
============================================================================

Principal Investigator:		Jolene S. Pickett
(Since Jan. 1, 2006)		Tel. 319-335-1897
				pickett@uiowa.edu

Former Principal Investigator:	Professor Donald A. Gurnett
(Up to Jan. 1, 2006)		Tel. 319-335-1967
				donald-gurnett@uiowa.edu

Cluster Systems Administrator:  Larry Granroth
                                Tel. 319-335-2536
				larry-granroth@uiowa.edu

WBD Science Team:  http://www-pw.physics.uiowa.edu/cluster/directory.html

============================================================================
============================================================================
