ISIS 3 Application Documentation
Update ISIS start times, pointing and spacecraft position with Gaskell
SUMFILEs
Description
Overview
This program allows the user to update a cube's labels, spaceraft attitude
(pointing) and position with more accurate information found in the
appropriate Gaskell SUMFILE. There are multiple options for the how the
labels should be updated. See the MODE parameter documentation for a
description of these options.
The Gaskell SUMFILEs provided are expected to have a format
described below:
-
Line 1: An ID for the SUMFILE (usually the image name).
-
Line 2: The correct start UTC for the image.
-
Line 3: The number of pixels, the number of lines, the lower DN
threshold, and the upper DN threshold.
-
Line 4: The focal length (in mm), followed by the pixel center and the
line center (i.e. boresight/optical axis).
-
Line 5: The vector from the spacecraft to the object center (i.e. the
spacecraft position in body fixed coordinates).
-
Line 6: The pixel (x) unit vector, in body fixed coordinates.
-
Line 7: The line (y) unit vector, in body fixed coordinates.
-
Line 8: The boresight (z) unit vector, in body fixed coordinates.
-
Line 9: The sun direction unit vector, in body fixed coordinates.
-
Line 10: The k matrix
-
Line 11: Used to contain distortion information, but it is always zero now.
-
Line 12: The formal spacecraft position uncertainty , ie. the sigma VSO.
-
Line 13: The formal spacecraft orientation uncertainty , ie. the sigma PTG.
-
A list of landmarks containing the ID, pixel center, and line center.
-
A list of limb fits containing the landmark-on-limb centers.
Here is an example:
W46908480918
2014 NOV 12 17:20:03.128
2048 2048 500 65535 NPX, NLN, THRSH
0.1356800000D+03 0.1044000000D+04 0.9380000000D+03 MMFL, CTR
-0.9665063720D+01 0.1326644487D+02 -0.6673084308D+01 SCOBJ
-0.6442479111D+00 -0.1829032409D-01 0.7645979944D+00 CX
0.5935707119D+00 0.6184779444D+00 0.5149357652D+00 CY
-0.4823053379D+00 0.7855892670D+00 -0.3875965231D+00 CZ
0.7254908676D+00 -0.3292717307D+00 0.6043534796D+00 SZ
74.07410 0.00000 0.00000 0.00000 74.07410 0.00000 K-MATRIX
0.00000D+00 0.00000D+00 0.00000D+00 0.00000D+00 DISTORTION
0.1007758363D-02 0.1482813397D-02 0.8902614968D-03 SIGMA_VSO
0.3071768580D-04 0.3093941486D-04 0.1565302183D-04 SIGMA_PTG
LANDMARKS
AO0001 2049.39 668.15
AO0002 2020.70 644.81
AO0003 2035.17 708.66
BD0009 1902.39 884.05
BD0010 1891.13 909.86
...
EK0022 675.73 1371.97
EQ0088 721.76 738.13
FI0002 727.77 220.40
LIMB FITS
END FILE
Usage
sumspice has been used to apply Gaskell control to Hayabusa Itokawa
AMICA images. There is up to 12 seconds of uncertainty in the start times
of these images. The Hayabusa team improved the start time with brute
force comparisons of the position of Itokawa in the AMICA field of view.
The SUMFILEs contained the correction of the start time. This was the
motivation behind adding support for the start time adjustment.
To apply the complete functionality of sumspice, the start time
must be updated first if required. Note that it is rather uncommon the
start time will need to be updated. If it is, this option will recompute
the SpacecraftClockStartTIme which is used primarily by most camera models
for best accuracy of image acquisition times. This mode will require a
rerun of spiceinit mainly to reestablish the body orientation for
the new start time.
The update of pointing attitude and spacecraft position requires
spiceinit to be applied to the image. This operation will update
the InstrumentPointing and InstrumentPosition Tables in the label of the
ISIS cube with the contents of the Gaskell SUMFILE. Note that SUMFILEs
contain vectors in body-fixed format, so you must ensure the proper PCK is
used with the image. NAIF routines are used to apply any required
transformations to retain the integrity of the data. Once the fidelity of
the updates are confirmed, new CK and SPK kernels can be created using the
ISIS ckwriter and spkwriter applications, respectively.
Categories
History
Kris Becker | 2015-02-25 |
Original Version
|
Jeannie Backer | 2015-12-07 |
Generalized to program work with Dawn and Hayabusa data. Clock times are
now updated in the instrument group and the original times are saved in
the Archive group of the cube labels.
|
Kris Becker | 2016-02-09 |
Added implementation to support NAIF META kernel files. Updated
documentation.
|
|
Parameter Groups
Files
Name
|
Description
|
FROM |
A single cube to process.
|
FROMLIST |
A list of cubes to process.
|
SUMFILE |
The name of the SUMFILE to be used to update the input cube(s).
|
SUMFILELIST |
A list of SUMFILEs to search for the best match to update the given
cube(s).
|
MODE |
Determines how the program will use the appropriate SUMFILE to update
the labels.
|
TIMEDIFF |
The maximum allowed time difference between the cube's current start
time and the time found in the SUMFILE.
|
METAKERNEL | List of SPICE kernels to support conversions |
|
Files:
FROM
Description
The name of a single input cube whose labels will be updated using a
Gaskell SUMFILE. Note: Use the FROMLIST parameter instead of
this one if there are multiple cubes to process.
Type
| filename |
File Mode
| input |
Default
| None |
Exclusions
|
|
Files:
FROMLIST
Description
A text file containing a list of input cubes whose labels will be
updated using Gaskell SUMFILEs. Note: Use the FROM parameter
instead of this one if there is only one cube to process.
Type
| filename |
File Mode
| input |
Default
| None |
Exclusions
|
|
Files:
SUMFILE
Description
The name of a single Gaskell SUMFILE containing an updated start time
and SPICE information. Note: Use the SUMFILELIST parameter
instead of this one if the exact SUMFILE that should be used
to update the cube(s) is unknown or if there are more than one.
Type
| filename |
File Mode
| input |
Default
| None |
Exclusions
|
|
Filter
| *.SUM |
Files:
SUMFILELIST
Description
A text file containing a list of Gaskell SUMFILEs that each contain an
updated start time and SPICE information. Note: Use the
SUMFILE parameter instead of this one if the exact SUMFILE is known
for the given cube(s).
Type
| filename |
File Mode
| input |
Default
| None |
Exclusions
|
|
Filter
| *.lis |
Files:
MODE
Description
Determines how the program will use the appropriate SUMFILE to update
the labels. Note that there are input requirements for each option.
Type
| string |
Default
| UPDATETIMES |
Option List:
|
Option |
Brief |
Description |
UPDATETIMES |
Update the start and end times in the cube's label.
|
If the UPDATETIMES option is selected, the program update the time
and clock values in the cube's Instrument group. If a single
SUMFILE is given, the program will use this file. If a SUMFILELIST
was provided, the program will search for the file in the given
list whose time is within the specified TIMEDIFF tolerance and is
the closest to the SpacecraftClockStartCount in the cube. If
multiple files in the SUMFILELIST have the same time, this program
will choose to use the first one in the list with the closest
time. If no SUMFILE is found within this tolerance, a warning will
be printed to the output log and the program will exit without
updating the input cube's labels. Otherwise, the UTC on the second
line of the SUMFILE will replace the StartTime value in the cube's
Instrument group. The ExposureDuration in the label is then used
to find the new StopTime. These new start/stop time values are
used to determine the new SpacecraftClockStartCount and the new
SpacecraftClockStopCount. The original values of these keywords
and the SUMFILE used to update the keywords will be saved in the
cube's Archive group.
|
UPDATESPICETABLES |
Update the InstrumentPosition and InstrumentPointing tables in the cube's label.
|
If the UPDATESPICETABLES option is selected, the program will
search for the SumFile keyword in the cube's Archive group. If
no such keyword exists or if the SumFile saved to the labels is
not found in the given SUMFILELIST, a warning will be printed to
the output log and the program will exit without updating the
SPICE tables. Otherwise, the spacecraft position and pointing
information will be updated using the information provided in the
matching SUMFILE. Requirements: to run sumspice using the
UPDATESPICETABLES option, the input cube must have already been
run through sumspice with the UPDATETIMES option and then run
through spiceinit.
Exclusions
|
|
Files:
TIMEDIFF
Description
This value is used when the UPDATETIME option is selected and a
SUMFILELIST is provided. The file in the SUMFILELIST with the time
that is closest to the cube's start clock must be within this
tolerance for the cube to be updated.