INIT_LITHOS.TXT

Category B

Version 3.0

Description

This text file sets limits, definitions, and logicals for SPC.

Here is a sample to show the keywords used in INIT_LITHOS.TXT.

Operational settings for INIT_LITHOS.TXT. There are other options, but they are not needed or supported for the OSIRIS-REx mission. # as the first character denotes a comment.

USR= '0'
USRMX=12
BODY='RQ36'
IDCODE=2101955
#BFRAME='RQ36_FIXED'
BFRAME='IAU_BENNU'
PCK='DATA/naif0011.tls'
PCK='DATA/bennu_v10.tpc'
UNIT='METER'
ASIG= 0.05
SSIG= 0.15
CHI0= 1.0
BLIM= 0.5
MXSLP=0.6
BLOOM=0.2
SEED= 1.3827453
#REFLECT= 'VESTA'
NEWLIM=.TRUE.       find new limbs in LITHOSP
SOFTEN=1
MAPONLY=.FALSE.
#GEOPIC='pict1.txt'
RENAME=.FALSE.
REGFLG=.FALSE.
REG='J0'
KB=1
RPLUSE=.TRUE.
RECVR=.FALSE.
#RECVR=.TRUE.
ALPAD=.TRUE.
NEWLIM=.TRUE.
DISTORT= 'M###########' 'OWEN'  6
0.00000D+00        0.00000D+00    0.0000000-06    0.00000D+00    0.00000D+00    0.000000D-05   0.0000000D-07
DISTORT= 'P###########' 'OWEN'  6
0.00000D+00        0.00000D+00    0.000000D-06    0.00000D+00    0.00000D+00    0.000000D-07   0.0000000D-06
#SHAPERF= 'SHAPEFILES/SHAPE00.TXT'
#SIGMARF= .05
LMKWTS= 1, 1, 1, 0      WB, WO, WL, WR
PICWTS= 1, 1, 0, 1, 0      WB, WL, WC, WS, WT
LPCORLM= 0.2
ALCORLM= 0.3
GDCORLM= 0.3
HTCORLM= 0.2
CORRFLG= 3         0:LAP, 1:ALB, 2:GRD, 3:L+A
RESLM= 4           PIXEL<RESLM*SCALE [SCALE>PIXEL/RESLM]
PICLM=2
NUMLM=200
SIZLM= 1.5        ^ LOWERS PIXEL/SCALE
END

Explanation

USR

Not used

USRMX

When running any batch script program (make_scriptP, make_scriptAP), this value defines the number of processors that will be used

BODY

The is the name of the object

IDCODE

The is the number that NAIF uses to denote the object. Bennu's official asteroid designator is 2101955

BFRAME

Contains the variable used to define the body fixed coordinate frame. This is defined by NAIF and used in the kernels

PCK

These define the planetary constants for a variety of objects. naif0011.tls is for the whole solar system. bennu_v10.tpc is the current version for Bennu. Many programs will read these line to do SPICE function calls.

UNIT

Sets the units that the tables report out units. Options are KILOMETER and METER

ASIG

The weighting that is placed upon the albedo solution (a priori albedo sigma). Typical is 0.05. EDIT JRW 09 May 2017: This value determines how much to change albedo during 0-0-40. Set it small means albedo won't change.

SSIG

The weighting that is placed upon the asteroid's topographic solution. (a priori slope sigma). Typical is 0.15

CHI0

Background limit. Typical is 1.0.

BLIM

Minimum overlap in LITHOS b option. Typical is 0.5.

MXSLP

Sets the limit for slope. Previous use at 0.6 ensures no vertical slopes. Suggest removing or 0 for Bennu and boulders.

BLOOM

Enables limb detection when blooming is present. Typical is 0.02.

SEED

The seed value used for the random function call.

REFLECT

What photometric model to use. If not defined, SPC uses McEwin .

SOFTEN

This decreases the weight of the change when a solution is found. Typical is 1.0.

MAPONLY

If .TRUE., we ignore mapless landmarks in GEOMETRY. Standard is FALSE

REGFLG

If .TRUE., it uses an alternate LANDMARK naming convention.

REG

If REGFLG=.TRUE., it uses these two characters as the lead character for LANDMARKS.

KB

Beginning number in sequence for LANDMARKS. Typical is 1

RPLUSE

Use PICTLISTX or PICLTLISTR for netpictures. Typical is .TRUE.

RECVR

If .TRUE., prevents high res maplets from effecting low-resolution topography. Typical is .FALSE.

ALPAD

Perform extra albedo solution after each iteration. Typical .TRUE.

NEWLIM

Tells lithosP to run the detect new limb routing when running an iteration.

DISTORT

Distortion matrix. It has four parameters. The first is an image name template where # is a wildcard. If the image name fits the template, then it will apply this distortion matrix. The next parameter is the distortion type. The third parameter is how many terms the distortion matrix's vertex has. The fourth parameter is the distortion matrix's vector.

SHAPEREF

If you want to constrain the model using a starting shape model (GEOMETRY option 1), that model is defined here. Typical is "SHAP00.TXT.

SIGMARF

Simga is km for above constraint. Typical is 0.5.

LMKWTS

Weights for generation for the LANDMARK position (GEOMETRY option 1). Typical is 1, 1, 1, 0 (see details below)

PICWTS

Weights for generation for the S/C position and pointing (GEOMETRY option 2). Typical is 1, 1, 1, 1, 0

LPCORLM

Correlation limit for laplacian cor. Typical is 0.2.

ALCORLM

Correlation limit for albedo cor. Typical is 0.3.

GDCORLM

Correlation limit for gradient cor. Typical is 0.3.

HTCORLM

Correlation limit for height cor. Typical is 0.2.

CORRFLG

Overlap correlation option. 0:LAP, 1:ALB, 2:GRD, 3:L+A. Typical is 3.

RESLM

PIXEL<RESLM*SCALE [SCALE>PIXEL/RESLM]. Limits image or maplet resolution in search. Typical is 4.

PICLM

Minimum number of images in a LANDMARK. If it doesn't this many, the LANDMARK is deleted. Typical is 6.

NUMLM

Number of images before RESLM kits in. If you have more that this number of images, don't add in resolutions ratios beyond RESLM. Typical is 200.

SIZLM

Minimum ratio of map to image sizes. MAPSIZE < SIZLM * PICSIZE. ^ LOWERS PIXEL/SCALE. Typical is 1.5.

BLEMISHES='FC2#########'

Reference to a template contained in BLEMISHES/ for masking bad pixels which are common to all FC2 images (example taken from DAWN). The template name is 12 characters, with the characters common to all affected images in the correct positions and '#' everywhere else. There may be multiple BLEMISH entries, each referring to BLEMISH template files.

PRNLM=100

Prune limit used by residuals to alert you if the number of pictures containing a landmark exceeds the limit. Landmarks exceeding the limit are listed in the output file PRUNE.TXT.

Weighting values for landmark and picture calculations.

Within INIT_LITHOS.TXT, we have weighting that goes into the solution. The actual weight that is included is the sqrt of the value provided. Thus, if you want to double the weight, you would use 4.

LMKWTS -- Landmark Weights

These weights are used to influence the position of the central vector -- the middle of the landmark.

PICWTS -- Picture Weights

These weights are what is used when solving for the spacecraft position and camera pointing.


(Compiled by KD)

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