Level 2 Help for NAV

INP

	EX:  INP=PIC
where PIC is the image to be navigated.  PIC must be a Voyager, Galileo or
Cassini image in either byte or halfword (16-bit integer) data format.  The
frame must be in image-space or object-space (no picture size reduction or
map-projection allowed).

Voyager images should be 800x800 for image-space frames and 1000x1000 for
object-space frames.  Galileo images are always in image-space and are
800x800 for full-frame images and 400x400 for summation-mode images.  Cassini
images can be 1024x1024, 512x512 or 256x256 and are always in image-space.

The frame does not have to be radiometrically corrected.  It will be desirable
to do so, however, if the PROFILE option is used to gather ring-profile data.


SPICEMODE

SPICEMODE=LOCAL specifies that SPICE data is to be accessed from local
SPICE kernels.  SPICEMODE=REMOTE specifies that SPICE data is to be accessed
via the SPICE server.  If SPICEMODE is defaulted, the logical name (or
environmental variable) DEFAULTSPICE is used to determine whether LOCAL or
REMOTE is used.

Note that if SPICE data is not found in LOCAL or REMOTE mode, the other mode
is attempted in order to retrieve SPICE data.  However, when improved camera
pointing data is stored, only the specified or default mode is used.


CKNAME

CKNAME is a four character string specifying the C-kernel to be used in reading
camera pointing data:

  CKNAME	C KERNEL
  --------      -------------
  DAVI		MIPS_DAVI.CK
  NAV		MIPS_NAV.CK
  FARE		MIPS_FARENC.CK
  NAV2		MIPS_NAV2.CK
  NEAR		MIPS_NEAR.CK
  AMOS		MIPS_AMOS.CK
  NAIF		the best NAIF kernel is used

If defaulted, the kernels are searched in the above order.


CKID

CKID is an alternative way to specify the prefered C-kernel for reading
camera pointing data (see CKNAME parameter):

  CKID	  CKNAME	C KERNEL
  ----	  --------      -------------
  M906	  DAVI		MIPS_DAVI.CK
  M905	  NAV		MIPS_NAV.CK
  M904	  FARE		MIPS_FARENC.CK
  M903	  NAV2		MIPS_NAV2.CK
  M902	  NEAR		MIPS_NEAR.CK
  M901	  AMOS		MIPS_AMOS.CK
  varies  NAIF		there are a large number of these files

Ex:  CKID=M901 specifies the four character ID which uniquely identifies the
     C-kernel MIPS_AMOS.CK.

A complete list of the C-kernel IDs is located in the ASCII file assigned the
logical name (or environmental variable) KERNELDB.

If specified, CKID overrides the CKNAME parameter.


INSTITUTE

INSTITUTE is a four character string identifying the facility which creates
the improved (C-Smithed) camera pointing.  If defaulted, the value of the
logical name (or environmental variable) VICAR_SITE is used.

Ex:  INSTITUTE=ASU identifies ASU as the creator of the improved camera
     pointing.


PURPOSE

PURPOSE is a four character string identifying the purpose of the observation
or the purpose of processing.  For example,
  PURPOSE=MOSA identifies the image as part of a mosaic sequence
  PURPOSE=COLO identifies the image as part of a color sequence


REQNUM

REQUNUM is a four character string identifying the IPL request number for
which the camera pointing was created.  REQNUM must contain exactly 4 digits.

Ex:  REQNUM=0123 identifies (somewhat) request number R000123


CDATE

Date and time the camera pointing was created in the form 'YEARMMDDHHMM'.
The date string must contain exactly 12 digits.

Ex:  CDATE=199602291200 specifies that the pointing was created at noon
     on February 29, 1996.

If defaulted, the current date and time is used.


GROUPID

GROUPID is a three character string which identifies the group of the user
running this program to store improved camera pointing.  (The user ID is
automatically determined by the program).

Ex:  GROUPID=040 identifies group 040 as the creator of the camera pointing.

On VMS, this parameter is ignored since the program automatically determines
the group ID of the current user.

If GROUPID is defaulted on Unix, the program uses the value of the
environmental variable GROUPID.  Note that GROUPID is not a system-defined
variable, and should be defined in your .cshrc as in the following example:

Ex:  setenv GROUPID 040


FRAME

INTEGER - Frame number of the input image.  For Voyager, this is the
   FDS Count specified as XXXXXYY where XXXXX is the Mod16 count and
   YY is the Mod60 count.  Default is the value in the picture label.


CAMERA

INTEGER - Camera serial number.  Default is the value in the picture
   label.  Valid Voyager camera serial numbers are:

	4 = VGR-2 WA		6 = VGR-1 WA
	5 = VGR-2 NA		7 = VGR-1 NA

       Galileo SSI has only one camera (serial number always 1).
       However, serial number of 2 is used for summation mode.

        Valid Cassini camera serial numbers are:
        1=NAC  21=NAC 2x2 summation mode  41=NAC 4x4 summation mode
        2=WAC  22=WAC 2x2 summation mode  42=WAC 4x4 summation mode


RES

STRING--OPTIONAL
Input reseau locations:
  Ex:  RESLOC  (PIC,RESFILE)  R		!Locate the reseau
       NAV  PIC  RES=R			!Input the reseau to NAV
The reseau locations must be input if the image contains geometric camera
distortions (i.e. if it is an image-space frame).


BLEMS

STRING--OPTIONAL
Input blemish locations:
  Ex:  VGRBLEM  PIC  B		!Retrieve the blemish locations
       NAV  PIC  BLEMS=B	!Input the blemishes to NAV
If defaulted, the program automatically accesses blemish files located
in WMS_VGR:[VGR1.NA], WMS_VGR:[VGR1.WA], and WMS_VGR:[VGR2], or the 
equivalent directories /project/vgr/vgr1/wa, /project/vgr/vgr1/na, and 
/project/vgr/vgr2 under Unix.

The program checks to ensure that the camera serial number associated 
with the file (as extracted from the label) matches the camera serial 
number associated with the image.


SAO

	EX:  SAO=VGR:[UID123]SAO.CAT
Specifies the file location of the Smithsonian Astrophysical Observatory (SAO)
or other star catalog.  The catalog is required for star navigation only.  At
MIPS the file sao_idl.str is located in WMS_VGR:[000000] if VMS, 
or /project/vgr under Unix.  Other star catalogs are available.
Outside users can get the sao.cat file from FEI using fei -g vgrrad/sao_idl.str
See HELP file for details on file contents and format.


GSCPFX

	EX:  GSCPFX=GSCVOL            !VMS
             GSCPFX="/cdrom/gscvol"   !Eunuchs(tm)

Specifies the prefix for ths location of the Guide Star Catalog CDROM's put 
out by the Space Telescope Science Institute.  If this parameter is specified 
then it will override the SAO parameter.

See HELP file for details on mounting the CDROM's.


OEF

	EX:  OEF=VGR:[UID123]OEF.DAT
Specifies the file location of the Orbital Elements File, which defines the
ring systems of the outer planets.  At MIPS, the orbital elements file is 
located in WMS_VGR:[000000] if VMS, or /project/vgr under Unix. This parameter
is required when the parameter RING is specified.
Outside users can get the ROEF.DAT file from FEI using fei -g vgrrad/roef.dat.


NLW

INTEGER - Length of correlation window in pixels.
    High contrast points (limb or ring) are determined by correlating
    with an edge function of area NLWxNSW.  Note that both NLW and
    NSW must be positive odd integers.


NSEARCH

INTEGER - Search radius (pixels).
Example: NSEARCH=11
    Starting at each computed limb (or ring) point, scan in a direction
    normal to the limb a distance + and - 11 pixels for high-contrast
    points.


CZOOM

INTEGER - Center display and zoom
Example: CZOOM=2
    Center the display around the current cursor position and magnify
    the image to twice normal resolution.


H

Display entire image.  The image may be displayed at reduced resolution
to accomplish this.


C

Read cursor positon.  Reports (line,sample) and (lat,lon) or (radius,lon)
coordinates.


HIST

KEYWORD - Overlay (in graphics plane) histogram of displayed image area.
  A logrithmic frequency scale is used.


SPIKES

INTEGER - Ex: SPIKES=n will scale the frequencies so that the n'th largest
  frequency corresponds to maximum scale.


STRETCH

INTEGER - Stretch the displayed image
Example: STRETCH=(25,100)
    A hardware stretch (linear transformation) is applied to the displayed
    image.


ASTRETCH

    ASTR=(lopercent,hipercent)
Entering ASTR=(0.5,1.5) will perform an "ends-in" stretch:  The
histogram of the displayed image area is first computed.  Low and
high stretch limits are then chosen so as to saturate 0.5 and
1.5 percent of the data at the low and high ends of the histogram
(respectively).  The algorithm is described in detail in the
help information for VICAR program FIT.


OVERLAY

INTEGER - Draw latitude-longitude grid
Ex: OVERLAY=30 draws parallels and meridians at 30 deg intervals


LATI

REAL - Draw a parallel
Ex: LATI=35.5 draws a parallel at latitude 35.5 degrees


LONG

REAL - Draw a meridian
Ex: LONG=180.0 draws a meridian a longitude 180.0 degrees


LL

REAL - Convert from lat-lon to line-sample
Ex: LL=(-35.2,183)


LS

REAL - Convert from line-sample to lat-lon
Ex: LS=(341,789.3)


RADIUS

REAL - Ring radius (km)
Example: RADIUS=136776
    A ring of radius 136776 km is displayed in graphics.


RING

STRING - Ring name. The ten Uranian rings are identified by the
following nomenclature:

	6 = ring 6		N = eta ring
	5 = ring 5		G = gamma ring
	4 = ring 4		D = delta ring
	A = alpha ring		L = lambda ring (1986U1R)
        B = beta ring		E = epsilon ring

 Saturns ring features are as follows:

        F = F ring              K = Outer Keeler gap
        E = Outer Encke gap     A = Inner A ring edge
        N = Cassini inner edge of outer ring
        S = Cassini inner edge of 4th outer ring
        W = Outer B feature     B = Inner B ring edge
        M = Maxwell gap         R = Mid C ring feature
        T = Titan gap           C = Inner C ring edge
 
For Neptune, nine test orbits have been defined, the first three with
polar orbits and the remainder with equatorial orbits.  These rings are
idenditied as follows:


          Polar rings      New Satellites        Previous
	A =  50000 Km	   5 = 1989N5  orbit     T = Triton orbit
	B = 100000 Km	   3 = 1989N3            N = Nereid orbit
	C = 150000 Km	   4 = 1989N4
			   2 = 1989N2
			   1 = 1989N1

E.g. RING=E
When RING is specified, the parameter OEF is required.


SRINGS

KEYWORD - Show ring system.  For Uranus, the ten known rings will
be displayed in graphics, their positions based upon current pointing
knowledge.


PREDICT

REAL (3) - PREDICT=FRAME: Longitude of cursored object is predicted
for FRAME assuming MASTER ring orbit.  Cursor determines current
object's MASTER radius and longitude.
PREDICT=(FRAME,RADIUS):  Longitude of cursored object is predicted
for FRAME assuming circular orbit of RADIUS in MASTER ring plane.
Cursor determines objects current MASTER longitude.
PREDICT=(FRAME,LONGITUDE): Position in current frame is determined
from MASTER longitude at different FRAME.
PREDICT=(FRAME,LONGITUDE,RADIUS): Position in current frame is determined
from MASTER longitude assuming circular orbit of RADIUS in MASTER plane
at different FRAME.


PROFILE

KEYWORD - Plot radial or longitudinal profile of specified ring sector.
The user will be prompted for radius and longitude boundaries of sector.


MASTER

STRING - Specifies master C-matrix.  All C-matrices are replaced by
the master C-matrix.
Ex: MASTER=D


ERING

KEYWORD - Enables editing of ring orbital parameters.


INNER

Inner edge of ring.
    Keywords INNER, OUTER, or THIN specity the type of edge function
    to apply when scanning for a ring radius.


STAR

Typing STAR invokes the STARFIT routine which navigates the image by
matching the stars in the image with a starmap computed from data
retrieved from the SAO catalog.


HIMAG

INT - highest magnitude star displayed.
!CBTC REAL - highest magnitude star displayed.


SSTARS

KEYWORD - Display starmap.


MSTARS

KEYWORD - Move (register) starmap.


RD

Typing RD=(76.7,15.5) will cause the cursor to be moved to that
right-ascension and declination on the display screen.  The corresponding
line-sample coordinates are reported.


GEODET

All input and output latitudes are reported as planetographic.
The default for Voyager is GEODET.  For all other projects, the default
is GEOCEN.


GEOCEN

All input and output latitudes are reported as planetocentric.


PC

REAL - Object-space planet-center (line,sample)
Example: PC=(433.2,315.3)
    The camera pointing is updated so that the planet-center is 
    located at (line,sample)=(433.2,315.3) in the image.


ISPC

REAL - Image-space planet-center (line,sample)
Example: ISPC=(433.2,315.3)
    The camera pointing is updated so that the planet-center is 
    located at (line,sample)=(433.2,315.3) in the image.  The input
    image must be an image-space frame.


WAPC

REAL - Object-space planet-center of VGR wide-angle frame.
The input frame is assumed to be the narrow-angle frame of a WA-NA
simultaneous exposure.  WAPC permits input of the planet-center
(line,sample) of the corresponding wide-angle frame.  The planet-center
for the narrow-angle frame is then derived using the known
transformation between the to camera fields-of-view.
EX: WAPC=(235.3,335.8)


WAISPC

REAL - Image-space planet-center of VGR wide-angle frame.  The input
frame must be in image-space and is assumed to be the narrow-angle
frame of a WA-NA simultaneous exposure.  WAISPC permits input of the
planet-center (line,sample) of the corresponding wide-angle frame.
The planet-center for the narrow-angle frame is then derived using
the known transformation between the to camera fields-of-view.
EX: WAISPC=(235.3,335.8)


ANGLN

REAL - North angle
Example: ANGLN=45.3
    The camera pointing is updated so that the planet's projected
    spin axis is oriented at a 45.3 degree angle, measured
    clockwise from up in the image.


RANGE

REAL - Spacecraft range (km).
    Distance from spacecraft to planet center.


RLIM

REAL - Minimum and maximum ring radii.  Used only to flag ring-obscured
limb points during limb scans.
EX: RLIM=(80000.,140000.)


TARGET

STRING - Target body name
Example: TARGET=SATURN


SAVE

KEYWORD - Save current navigation or orbital data.


RESTORE

KEYWORD - Restore previously saved navigation or orbital data.  If no
previous values were saved, initial values are retrieved.


GETSEDR

KEYWORD - Retrieve navigation data from SEDR.  This restores the
nominal camera pointing.


PIZERO

REAL - Longitude of periapse measured at Epoch.  For Uranus, French's
epoch is 20:00 UT on 10 March 1977.  For Saturn, Porco's epoch is
time of Voyager 1 closest approach.  For Neptune, the epoch is time of
Voyager 2 closest approach.


OMEGZ

REAL - Longitude of ascending node measured at Epoch.  For Uranus, French's
epoch is 20:00 UT on 10 March 1977.  For Saturn, Porco's epoch is
time of Voyager 1 closest approach.  For Neptune, the epoch is time of 
Voyager 2 closest approach.


RA

REAL -  Right ascension of planet's pole (assumed constant)


DEC

REAL - Declination of planet's pole (assumed constant)


SCLAT

Sub spacecraft planetocentric latitude in degrees.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


SCLON

Sub spacecraft longitude in degrees east.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


SUNLAT

Sub solar planetocentric latitude in degrees.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


SUNLON

Sub solar longitude in degrees east.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


CENTLINE

Line of planet center.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


CENTSAMP

Sample of planet center
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


RANGE

Distance from spacecraft to planet center in KM.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


FOCAL

Camera focal length in mm.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


SCALE

Camera scale in pixels/mm.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


NORTH

The angle measured in degrees clockwise from up of the projection of the
planet spin axis (north end) normally onto the image plane.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


OALINE

Line of the camera optical axis.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


OASAMP

Sample of the camera optical axis.
Normally this is obtained from the input label(s).
Only valid for non-flight projects.


CLEAN

INTEGER - Clean bad points
Example: CLEAN=5
    All high-contrast points within a 5 pixel radius of the current
    cursor position are deleted from the acquired curve.


SEF

The SEF command is for program development only.  Don't try it.