geometry

(Compiled by TC)

BACK UP YOUR WORK BEFORE RUNNING GEOMETRY

Description

Makes a surface by solving for the spacecraft position, spacecraft pointing, and landmark locations. This procedure iterates the solutions for camera pointing and landmark vectors sequentially. The inputs are a list of operations where 1=landmark vectors, 2=camera pointing, 0=END, the number of iterations desired, a choice of whether to use limbs in determining camera pointing (y/n), and a option to do it all over again (y/n). For example,

• GEOMETRY

  120<- do 1 followed by 2 30 <- do them 30 times y <- use limbs for pointing n <- stop when done GEOMETRY

  20 <- do 2 only 10 <- do it 10 times n <- don't use limbs for pointing n <- stop when done

The default is to do these operations for all landmarks in LMRKLIST.TXT and all images in PICTLIST.TXT. If INIT_LITHOS.TXT contains a record

GEOPI='filename1'

or

GEOMAP='filename2'

then the files used are reduced - filename1 instead of PICTLIST.TXT and filename2 instead of LMRKLIST.TXT.

Requires

• LMKFILES/

• IMAGEFILES/

• PICTLIST.TXT

• LMRKLIST.TXT

• LMRKLIST1.TXT

• MAPFILES/

• INIT_LITHOS.TXT

• SHAPE.TXT - This is the shape model that is stored in directory SHAPEFILES/.

• SUMFILES/

Input stdin

• 1: landmark vectors.
• 2: camera pointing, scobj
• 0: end.

• input operation list

   120

• enter number of iterations

   3

• use limbs for pointing? (y/n)

   y

• continue? (y/n)

   n

Output

• SUMFILES/

• LMKFILES/

• MAPFILES/

PowerPoint Notes

Geometry Estimation Terms

• Spacecraft State - Position and orientation of spacecraft affects size and location of the body in an image. Errors are reflected by offsets of extracted image data from maplets for all maplets in the image.
• Control Point Location - An error in the body-fixed control point location is reflected by offsets of extracted image data for all images containing the maplets.
• Rotation - An error in the transformation from inertial to body fixed frames is reflected in time-dependent offsets in extracted image data for all maplets in all images.
• Differential Stereo - Errors in the maplet heights relative to the center are reflected by differential shifts of features within the extracted image data in addition to displacements from the maplets themselves.

More in Depth Description of Geometry

• Global solution for camera pointing and body-fixed maplet location.
• Iterative process:
  • Weighted least-squares solution of landmarks (control points) based on:
    • Nominal camera pointing and position
    • Relative landmark-to-landmark location
  • Weighted least-squares solution of camera position and pointing based on landmark location