PDS_VERSION_ID      = PDS3
RECORD_TYPE         = STREAM

OBJECT              = TEXT
  PUBLICATION_DATE  = 2021-09-20
  NOTE              = "This file describes the timing issue
                      and the offset application."
END_OBJECT          = TEXT
END


Timing error and offset application

Owing to flight software issues, there can be a variable amount of error in
the reporting of the image start time (typically on the order of a few tens
of milliseconds in the worst case).  This can be significant when
map-projecting or georeferencing images.  When feasible, we attempt to reduce
this error by measuring the predicted position of the 1-bar limb with its
actual position in image pixels for the first framelet that contains the
planet.  An offset of N pixels corresponds to a timing error of N/311.2
seconds at the nominal spin rate of the spacecraft.  The start time of the
image is then updated appropriately, so that subsequent software processing
does not need to be aware of the offset.

For reference, the EDR_TIMING_OFFSETS.TXT and RDR_TIMING_OFFSETS.TXT files in
this directory are provided for images which were processed in this manner.
It is recognized that factors such as departure of the planet's shape from
the IAU spheroid and the optical depth of the limb leave residual errors,
even after this process has been applied.

If the offset in the last column is a floating point value other than 0.0,
then an offset was applied to the image.  If the value is 0.0, then an
offset was not needed for the image.  If the value is NULL, then an
offset was not able to be determined (e.g. curvature too steep, limb apex
in shadow).

Timing offsets were applied to both RGB and Methane images in a given
Perijove swath.  Note: single band visible spectrum images are not included
in this list.  The specific start and end times for each Perijove swath can
be found below.

PJ01: 2016-240T11:58:35.370 - 2016-240T13:58:39.158
PJ02: Safe mode, no images acquired
PJ03: 2016-346T15:45:47.276 - 2016-346T18:17:25.134
PJ04: 2017-033T12:09:17.802 - 2017-033T14:07:53.403
PJ05: 2017-086T07:30:52.604 - 2017-086T10:41:15.757
PJ06: 2017-139T04:46:46.264 - 2017-139T07:55:59.859
PJ07: 2017-192T01:10:57.169 - 2017-192T03:09:58.750
PJ08: 2017-244T21:05:44.006 - 2017-244T23:06:10.446
PJ09: 2017-297T16:52:46.760 - 2017-297T19:27:00.381
PJ10: 2017-350T16:39:11.911 - 2017-350T20:28:32.500
PJ11: 2018-038T12:52:23.038 - 2018-038T16:37:44.562
PJ12: 2018-091T08:09:49.991 - 2018-091T11:46:58.421
PJ13: 2018-144T03:50:43.588 - 2018-144T07:54:36.383
PJ14: 2018-197T03:32:45.150 - 2018-197T07:19:05.316
PJ15: 2018-249T23:27:00.273 - 2018-250T03:11:18.938
PJ16: 2018-302T20:09:58.360 - 2018-302T22:40:46.648
PJ17: 2018-355T16:09:23.706 - 2018-355T18:50:34.390
PJ18: 2019-043T15:50:06.034 - 2019-043T19:32:41.868
PJ19: 2019-096T13:05:48.190 - 2019-096T14:45:58.975
PJ20: 2019-149T07:29:47.963 - 2019-149T10:34:16.821
PJ21: 2019-202T03:21:56.717 - 2019-202T06:41:39.829
PJ22: 2019-255T03:02:54.739 - 2019-255T06:21:56.748
PJ23: 2019-307T21:38:13.324 - 2019-308T00:17:43.458
PJ24: 2019-360T16:56:56.782 - 2019-360T19:59:15.760
PJ25: 2020-048T17:09:05.460 - 2020-048T20:23:21.536
PJ26: 2020-101T13:12:40.790 - 2020-101T15:48:30.033
PJ27: 2020-154T09:42:01.255 - 2020-154T12:33:06.341
PJ28: 2020-207T05:34:49.621 - 2020-207T08:29:44.985
PJ29: 2020-260T01:29:57.861 - 2020-260T04:23:59.071
PJ30: 2020-313T01:13:12.715 - 2020-313T04:04:28.760
PJ31: 2020-365T21:05:51.647 - 2020-366T00:14:57.629
PJ32: 2021-052T17:01:48.065 - 2021-052T20:09:55.657