sumspice

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.