PDS3_DATA_SET_ID = VG1-J-POS-6-SUMM-S3COORDS-V1.1
DATA_SET_NAME = VG1 JUP EPHEMERIS SYSTEM III (1965)
COORDS BROWSE V1.1
START_TIME = 1979-03-03T00:00:35.978
STOP_TIME = 1979-03-16T23:59:56.185
ORIGINAL_DATA_SET_RELEASE_DATE = 1998-05-01
PRODUCER_FULL_NAME = Ness, N. F.; Acuna, M. H.; Lepping, R. P.;
Connerney, J. E. P.; Behannon, K. W.;
Burlaga, L. F.; Joy, S. P.
DATA-SET_SOURCE = NATIONAL SPACE SCIENCE DATA CENTER
REFERENCES:
Acton, C.H., Ancillary Data Services of NASA's Navigation and Ancillary
Information Facility, Planet. Space Sci., Vol. 44, No. 1, pp. 65-70, 1996.
Dessler, A.J., Physics of Jovian Magnetosphere Coordinate Systems, Physics
of the Jovian Magnetosphere, 1983.
DATA_SET_DESCRIPTION
Data Set Overview
=================
Version 1.1
-----------
The SEDR based data provided as part of this data set were
originally reviewed and archived with the NSSDC and PDS as
version 1.0 (DATA_SET_ID = VG1-J-POS-4-48.0SEC). Version 1.1
includes additional columns not present in the previous
version, 96 second rather than 48 second time samples, times
converted to 'PDS Style' or ISO standard, and upgrading of
PDS labels and templates to version 3.2. The SPICE based
data that are also part of this data set were not previously
archived with the PDS. This version 1.1 data set replaces
previously archived versions.
Data Set Description
--------------------
This data set consists of Voyager 1 Jupiter encounter
ephemeris data in System III (1965) left handed coordinates
covering the period 1979-03-03 to 1979-03-16. Two versions,
both covering the same time period, but containing slightly
different data, are provided. One version was generated by
the Voyager MAG team from Voyager 1 SEDR, the other by the
PDS/PPI node using the VG1_JUP.BSP and PCK00003.TCP SPICE
kernels. (Note: These SPICE kernels are not currently archived in PDS,
but they are available from NASA's Navigation and Ancillary
Information Facility (NAIF), https://naif.jpl.nasa.gov/naif/index.html)
Two versions of the spacecraft ephemeris data are provided as
an attempt to correct some of the problems in the Voyager
SEDR while preserving the ability to reproduce early results.
The original SEDR data has a variety of problems which may
affect the knowledge of the spacecraft position, or
conversely, the timing associated with certain events such as
ring plane crossings. The SPICE SPK kernel provided on this
disk includes corrections to some, but not all, of the
problems associated with the Voyager SEDR. The Navigation
and Ancillary Information Facility (NAIF) at JPL may issue a
new Voyager SPK kernel in the future that will further
improve the knowledge of the spacecraft location in inertial
space.
There are other differences in the in the two versions of
ephemeris data that are the result of improvements in the
knowledge of some of the physical constants associated with
Jupiter and its moons. Since the Voyager era, there have
been updates to the orientation of the jovian spin axis right
ascension and declination, the radius of Jupiter, as well as
the orbital characteristic and other physical parameters of
many of the moons of Jupiter. These changes affect the
stated position of the spacecraft in jovigraphic coordinate
systems like System III without changing the position of the
spacecraft in inertial space. The spin rate of Jupiter is
not changed from the System III (1965) rate of 9h 55m
29.71sec (870.536 deg/day). The SPICE planetary constants
kernel (PCK) contains both the current IAU definitions of the
physical constants for the bodies within in the jovian system
(as data) as well as the older IAU definitions (as comments).
This is an ASCII text file (PCK00003.TCP) and users of the
ephemeris data are encouraged to review it.
SEDR generated ephemeris
------------------------
Data Supplier : Ness, N. F.; Acuna, M. H.; Lepping, R. P.;
Connerney, J. E. P.; Behannon, K. W.;
Burlaga, L. F.
Data sampling rate : 96 seconds
Data Set Start Time : 1979-03-03T00:00:35.978Z
Data Set Stop Time : 1979-03-16T23:59:08.185Z
SPICE generated ephemeris
-------------------------
Data Supplier : S. Joy
Data sampling rate : 48 seconds
Data Set Start Time : 1979-03-03T00:00:35.978Z
Data Set Stop Time : 1979-03-16T23:59:56.185Z
Parameters
==========
SEDR generated ephemeris
------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 96.0 Sec time of the sample (UT) in the format
yyyy-mm-ddThh:mm:ss.sssZ
m65536 counts spacecraft clock counts
mod60 counts
fds_line counts
sc_x R[J] jovicentric (System III) cartesian
sc_y R[J] cartesian position vectors: X, Y, and
sc_z R[J] Z
vel_x km/s jovicentric X, Y, and Z spacecraft
vel_y km/s velocity components
vel_z km/s
sc_r R[J] jovicentric (System III) spherical
sc_lat degrees coordinates position vectors: range,
sc_lon degrees latitude, and longitude
CartSys3_to_SphSys3 cartesian system III to spherical
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SC_to_CartSys3 payload (spacecraft) to cartesian
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SC_to_SphSys3 payload (spacecraft) to spherical
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SPICE generated ephemeris
-------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 48.0 Sec time of the sample (UT) in the
format yyyy-mm-ddThh:mm:ss.sssZ
R Rj jovicentric (System III 1965)
LAT degrees spherical coordinates position
LON degrees range, latitude, and longitude
LocTime hours angular separation between the
meridian containing the sun and the
one containing the spacecraft
converted to a time. The sun meridian
is defined to be noon (12.000), with
midnight (0.000) opposite it. Dawn
(6.000) and dusk (18.000) are where
the sun rises and sets according to
the planet's rotation
Coordinate System
=================
The System III (1965) is a jovicentric left handed coordinate
system defined such that longitude increases with time as
viewed by a stationary remote observer.
Jovicentric cartesian (Jupiter fixed) coordinates
X points along the Jupiter-Sun line in the solar
equatorial plane (positive towards the Sun)
Y completes the right handed set
Z points along the jovian spin axis, positive
Jovicentric System III (1965) spherical coordinates
R Jupiter to spacecraft range (positive away from
Jupiter)
LAT completes the left handed, orthogonal set
LON System III (1965) east longitude (with longitude
increasing eastward from a specific jovian prime
meridian)
SPICE ephemeris were generated using the current definition of
the Jovian radius, 71492 km. The spin rate used in generating
these data is the same as that used for System III (1965),
+870.536 degrees/24 hours.
Data Coverage
=============
Filename Records Start Stop
-------------------------------------------------------------------
SEDR062 1623 1979-03-03T00:00:35.978Z 1979-03-04T23:58:59.925Z
SEDR064 6071 1979-03-05T00:00:35.925Z 1979-03-11T23:59:08.059Z
SEDR071 4370 1979-03-12T00:00:44.059Z 1979-03-16T23:59:08.185Z
SPICE062 3246 1979-03-03T00:00:35.978Z 1979-03-04T23:59:47.925Z
SPICE064 12142 1979-03-05T00:00:35.925Z 1979-03-11T23:59:56.059Z
SPICE071 8740 1979-03-12T00:00:44.059Z 1979-03-16T23:59:56.185Z
CONFIDENCE_LEVEL_NOTE
Confidence Level Overview
=========================
SPICE generated ephemeris
-------------------------
The SPICE generated data were derived from SPICE using
software that has been extensively tested. They should give
as accurate representation of spacecraft ephemeris as
possible using these kernels.
Comparisons between these data and other data from previous
Jupiter missions should be performed with caution. Some key
parameters, such as the Jovian radius, have changed from
mission to mission. Definitions for Jupiter's spin rate and
the orientation of its spin-axis have also changed slightly
since the pre-Voyager days.
Missing Data Flag
=================
Any SEDR generated ephemeris data column whose value is
-9.99999999e+10 is a missing data value.
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