| DATA_SET_DESCRIPTION |
Data Set Overview
=================
This data set contains data acquired by the Galileo Magnetometer
during the Interplanetary Cruise to Jupiter. The data are at varying
resolution depending on the averaging constant applied to the
instrument. The EDR files (Experimentor Data Record) were delivered to
the Galileo Magnetometer Team by the Galileo project. The EDR files
are given in IBM 370 binary representation and are stored in an
extremely compact format. The structure of the EDR files is completely
described in the documents GLL280 and GLL640. The pages pertinent to
the MAG description have been scanned into bit map images (TIFF) that
are stored in the /DOCUMENT directory off the root of this volume.
Data Acquisition
================
The data for this dataset were acquired as part of the normal
instrument calibration activities associated with the cruise to
Jupiter. As such, the instrument was commonly configured in modes
which required calibration even though they may not have been the
optimal mode for science data acquisition. The Galileo magnetometer
has 8 possible LRS acquisition configurations (modes). There are two
sensor triads mounted 6.87 and 11.03 meters from the rotor spin axis
(inboard and outboard) along the boom. Each of the sensor triads has
two gain states (high and low). In addition, the sensor triads can be
'flipped' to move the spacecraft spin-axis aligned sensor into the
spin plane and visa versa. Please see the instrument description for
full details on the instrument, sensors, and geometries. The
combinations of sensor, gain state, and flip direction form modes.
______________________________________________________________________
Mode Characteristics
______________________________________________________________________
Mode Name Acronym range quantization
______________________________________________________________________
Inboard, left, high range* ILHR +/- 16384 nT 8.0 nT
Inboard, right, high range* IRHR +/- 16384 nT 8.0 nT
Inboard, left, low range* ILLR +/- 512 nT 0.25 nT
Inboard, right, low range* IRLR +/- 512 nT 0.25 nT
Outboard, left, high range* ULHR +/- 512 nT 0.25 nT
Outboard, right, high range* URHR +/- 512 nT 0.25 nT
Outboard, left, low range* ULLR +/- 32 nT 0.008 nT
Outboard, right, low range* URLR +/- 32 nT 0.008 nT
__________________________________________
Summary of Mode Changes
__________________________________________
s/c clock date/time mode
__________________________________________
00104651:00:0 89-353/20:53 ULLR
00120107:00:0 89-364/17:21 URHR
00120117:00:0 89-364/17:31 IRHR
00120150:00:0 89-364/18:04 IRLR
00120178:00:0 89-364/18:33 ILLR
00120199:00:0 89-364/18:54 ILHR
00120209:00:0 89-364/19:04 URHR
00120231:00:0 89-364/19:26 URLR
00120283:00:0 89-364/20:19 ULLR
00120313:00:0 89-364/20:49 ULHR
00572976:00:0 90-040/03:00 ULHR
00572976:00:0 90-316/17:00 ULLR
00578673:00:0 90-320/17:00 URLR
00586204:00:0 90-325/23:55 URHR
00592915:00:0 90-330/17:01 ILLR
00597439:00:0 90-333/21:15 IRLR
00610156:00:0 90-342/19:33 IRHR
00610509:00:0 90-343/01:30 IRLR
00615701:00:0 90-346/17:00 URLR
00618550:00:0 90-348/17:00 URHR
00624261:00:0 90-352/17:15 ULHR
01072247:00:0 91-302/06:39 ULHR
01600269:00:0 92-308/00:48 ULLR
01605562:00:0 92-311/18:10 ILLR
01629549:00:0 92-328/14:14 IRLR
01632087:00:0 92-330/09:00 ULLR
01635479:00:0 92-332/18:23 URHR
01638675:00:0 92-335/00:01 URLR
01639786:00:0 92-335/18:45 IRLR
01639974:00:0 92-335/21:55 URLR
01640958:00:0 92-336/14:30 IRLR
01641285:00:0 92-336/20:40 URHR
01641351:00:0 92-336/21:07 IRHR
01641407:00:0 92-336/22:15 ILHR
01641465:00:0 92-336/23:02 URLR
01642481:00:0 92-337/16:22 ULHR
01644143:00:0 92-338/20:10 IRLR
01646048:00:0 92-340/04:16 ILLR
01649533:00:0 92-342/15:00 ULLR
01650524:00:0 92-343/07:42 ULHR
01650907:00:0 92-343/14:09 ILHR
01651026:00:0 92-343/16:10 ULHR
01656418:00:0 92-347/11:01 ILLR
01659057:00:0 92-349/07:30 ULLR
02035626:00:0 93-240/16:51 ULLR
* range is the opposite of gain
In addition to exercising the various instrument modes during the
first earth encounters, numerous instrument calibration activities
were performed. These include using both the internal and external
calibration coils. Data corrupted by the use of the calibration coils
or by the flipper motor have been removed from the raw data and kept
in seperate calibration directories.
Coordinate Systems
===================
The EDR data are being archived in inertial rotor coordinates (IRC).
This coordinate system has the Z axis along the rotor spin axis,
positive away from the antenna and the X and Y axes lies in the rotor
spin plane. In a crude sense, when the spacecraft is far from Earth,
+X points south, normal to the ecliptic plane, positive Y lies in the
ecliptic plane in the sense of Jupiter's orbital motion and positive Z
is in the anti-earth direction. The spacecraft antenna (negative Z
direction) is kept earthward pointing to about +/- 10 deg accuracy.
Data Processing
===============
The EDR files can be 'unbundled' using the software entitled
'unbundle_mro80' or 'unbundle_mro32'. The unbundling software will
read in a raw EDR and convert the data to IEEE binary flatfiles
(tables of data). Prior to doy 169 1993 the EDR's were delivered to
the magnetometer team by the Galileo Project in a 32 byte format. The
appropriate software to unbundle EDR data in a 32 byte format is
'unbundle_mro32'. After doy 169 1993 the Galileo Project delivered EDR
data in an 80 byte format. The appropriate software to unbundle the 80
byte format data is 'unbundle_mro80'. More information regarding this
software can be found in the SOFTWARE directory of this CDROM.
Information regarding the structure and format of the EDR binary file
is contained in the documents GLL280 and GLL640. The pages pertinent
to the MAG description have been scanned into bit map images (TIFF)
that are stored in the DOCUMENT directory off the root of this
volume.
|
| CITATION_DESCRIPTION |
Kivelson, M.G., Khurana, K.K.,
Russell, C.T., Walker, R.J., Joy, S.P.,Green, J.,
GALILEO MAGNETOMETER CRUISE EDR DATA,
GO-SS-MAG-2-EDR-CRUISE-V1.0, NASA Planetary Data System,
1996
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