Survey/ reflector info

02mar18

Survey coordinate systems

Target location on reflectors

Reflector definition files

reference positions:


Survey coordinate systems

    Various coordinate systems are used during surveys.

Dome center line coordinates:(DCL)


Dome Enclosure drawing (.pdf)

Ray trace  coordinate system (RTC)

Primary coordinate system:


Target locations on reflectors

     Lynns description in PNLFDCL directory:

    This subdirectory contains all the data pertaining to the target fiducials on the secondary and tertiary panels.  There is a file for each of the two reflectors named target.dat in both cases.  This file contains the measured locations of the panel fiducial holes in the dome C/L coordinate system and units of inches.  These fiducials were measured on a coordinate measuring machine at RSI when the panels were fabricated.

    When calculating reflector errors it is necessary to have the unit normals to the panel at the fiducial point.  The normals at the fiducial points are obtained from fortran software included in this subdirectory.  The software is a parametric spline interpolation system.  The reflectors are defined by a dense set of points and this interpolation system.  The dense set of points is in the file scndry.dat for the secondary and trtry.dat for the tertiary (these are the ray trace files pjp..)  The data in these files is from the PSK shaping software and is in the ray trace coordinate system and units of feet.

    The basic function of the fortran interpolation system is to accept a r,phi parametric variable pair and calculate the corresponding x,y,z coordinates on the reflector surface.  The software also produces the surface derivatives which can then be used to obtain the surface normals and jacobian of the mapping from parametric space to physical space.  The interpolation system is contained in the two fortran files interp2d.f and surfac.f which are common to both reflectors and contained in the upper directory.

    The calculation performed here is the inverse of basic interpolation.  Given a physical point, calculate the corresponding r,phi parametric variables and then the surface normal and jacobian at that point.  The fortran files scndry_fdcl.f and trtry_fdcl.f perform these tasks.  It starts by reading the file of reflector data points and initializing the interpolation system.  It reads the file of fiducial points and finds the corresponding parametric variables with a root find routine.  It then calculates the unit surface normal and jacobian at that point.  All of the results are output to a file called fiducial.tbl for each reflector.

Secondary targets

    There are two sets of  files holding the complete target set.

set #
targets
bytes
fileTimeStamp
file locations
1
All reflector targets except the masked over targets on the first row. Includes the 4 vertex points at the beginning.
1630
53433 22feb99
L3/align/PNLFCL/scndry/target.dat
L3/align/year99/PNLFDCL/scndry/target.dat
L3/greg/scndry/pnlset/target.dat
2
all reflector targets and 4 vertex points at the beginning

1661
67678
31oct03
L3/align/PNLFCL/scndry/archive/target.dat
L3/align/year99/PNLFDCL/scndry/archive/target.dat






Measuring, adjusting the reflectors, then using a subset define the dome centerline coord sys for tert, horn measurements.
    Videogrammetry was used to measure the locations of the targets on the reflector:

    The optics in the dome is referenced to the secondary. When aligning a horn (or  the tertiary), a theodolite is used. The steps are:

    The 54 target positions will get updated every time a  videogrammetry survey of the secondary is done. The .dsn files will get updated with the new positions.
We want to use the actual positions of the targets in dome centerline rather than the theoretical ones.. since the theodolite distance is to the actual dome CL position
rather than the theoretical one.

    The table below shows .dsn files that have been used over time. I've included the secondary surveys (which should have generated updated files after being processed.).
The latest .dsn file looks to be the one used on 28jun04.


date of
measurement
#targets
set 1st used
file location
assumed source  of dataset
121102
39
990619 L2/121102/secref2.dsn
pre 1999
121031
50
990619 L2/AO_align_old_laptop/year12/oct3112/secref1.dsn
121030 54
990619 L2/AO_align_old_laptop/year12/oct3012/secref.dsn
videogrametry sec  24-28jun04
040628
54
040628
L2/AO_align_old_laptop/year04/jun2804/scndry1/secref.dsn
This is from last day of sec videogrammetry.
040628VidGram?
040628_o
54
040409 L2/AO_align_old_laptop/year04/jun2804/scndry1/secref_old.dsn 031111VidGram
040508
54
040409 L1/040508/pc/secref.dsn
031111VidGram
040502
54
040409 L2/AO_align_old_laptop/year04/may0204/secref.dsn 031111VidGram
040501
54
040409 L2/AO_align_old_laptop/year04/may0104/secref.dsn 031111VidGram
040428
54
990619 L2/AO_align_old_laptop/year04/april2804/secref.dsn pre 1999
040409AM
040409PM
54
040409 L3/AO_data_old_desktop/align/year04/april0904/AM/secref.dsn
L3/AO_data_old_desktop/align/year04/april0904/PM/secref.dsn
031111VidGram
040225
54
990619 L3/AO_data_old_desktop/align/year04/feb2504/secref.dsn pre 1999
040214
54
990619 L3/AO_data_old_desktop/align/year04/feb1404/secref.dsn
pre 1999
031111 videogrammetry of secondary
020331
54
991021 L2/AO_align_old_laptop/year02/mar3102/secref.dsn
jan99-jun99Surv
010801
54
991021 L2/AO_align_old_laptop/year01/aug0101/secref.dsn jan99-jun99Surv
010730
54
991021 L2/AO_align_old_laptop/year01/july3001/secref.dsn jan99-jun99Surv
000201
54
991021 L2/AO_align_old_laptop/year00/feb0100/secref.dsn jan99-jun99Surv
991021
54
991021
L2/AO_align_old_laptop/year99/oct2199/secref.dsn jan99-jun99Surv
990619
54
990619
L2/AO_align_old_laptop/year99/jun2499/secref.dsn pre 1999
06jan99 to 23jun99 survey of secondary with theodolite.










Reflector definitions.

    The reflector definition files were provided by lynn baker (via don campbell) in 2013.
The files initially sent to mike shields at mit so he could put our reflector system into grasp.
They are the positions where rays cast from the focal point cross the various reflectors. They are not
the locations of the targets on the reflectors.

Lynn's notes:

 Attached are three ascii files corresponding to the tertiary, secondary
and primary reflectors.  Of course the primary is a sphere but I include
the file to help with orientation.  The file organization is in a "ray
trace" parametric format.  Imagine a bundle of rays emanating from the
focus and propagating through the optics.  Each ray reflects from each
reflector forming a set of three points associated with that ray.  These points
are tabulated for each ray in the following format.  There are 64+2
elevation angles giving 66 blocks at constant elevation angles.  Within each
block there are 128 azimuth angles.  The first point in each block is
repeated at the end of each block, giving a closed loop.  The first 64 blocks
 of data correspond to the physical reflectors.  The last two blocks are
extension data points beyond the physical edge of the reflectors. These
are included to help keep interpolants well behaved at the edges.  The
first data blocks in each file are degenerate in the sense that the loop in
azimuth is a single point.  Of course there is spherical reflector beyond
 the edge of the physical ray trace and the simulation should include that
The units are in feet.

The coordinate system origin is at the paraxial point, the half radius
point of the sphere, radius=870.0'.  The ray that goes the center of the
sphere is the paraxial ray and forms the z axis.  The y axis is perpendicular
to the symmetry plane and the x axis forms an RH system.

The focal point is located at         ( -29.5, 0, -19.,5 ). 
The boresight point on the tertiary is
(-29.5,0,  -32.
The angle from the focus to the boresight point is 1.736 degrees.
 The nominal edge taper on the tertiary

designed into the optics is -16 db. which maps to a nearly uniform
aperture illumination.  This leads to a roughly -16 db. first sidelobe in the
far field pattern.  Ideally it would be good to taper the aperture
illumination for a lower first sidelobe but that concentrates more power under
the platform blockage and that causes problems.


Table of different design files on disk
Some abbreviations:

location
suf
Match
ref
bytes
pri,sec,ter
hdrline
notes
L1
.data
Y
566047,566047,566047 64   128  2
current reference
L3/align/PNLFCL/scndry
.data
Y (-w)
 x,574496,x
64   128  2 only secondary. MIW
L3/align/PNLFCL/trtry .data
Y
x,x,566047
64   128  2 only tert.
L3/align/PNLFCL/year99/scntry .dat
Y (-w)
x,574496,x
64   128  2 only sec. MIW
L3/align/PNLFCL/year99/trtry .dat
Y
x,x,566047 64   128  2 only tert.
L3/fnlchk/
.dat
Y
x,566047,566047
64   128  2
L3/greg/scndry/pnlset
.dat
Y x,566047,x
64   128  2
L3/greg/trtry/pnlset .dat
Y x,x,566047
64   128  2
L3/greg/set11
.data
Y
566048,566048,566048
64   128  2
.old
N
668354,668424,668354
64   128  2 2nd line: 1
.orig
N
668358,668428,668555
64   128  2 2nd line: 1
L3/greg/set10 .data
N
445983,445983,445983
25   128  1
looks like fewer blocks.
.orig
N
1269234,1268888,1268206
25   128  1 2nd line: 1
some lines 3 #, some 4 #
L3/greg/set8 .data
N
x,184489,184489
25   1   129
looks like this is old hdrline format



Reference positions:

    I tried to gather together the current reference values used for surveying. Each entry includes a description and a reference to where is came from.
object
value
description
Horn focus in
DomeCenterline
x
inches
y
inches
z
inches
TiltX
deg
TiltY
deg
-248.145 0.
-389.822 .625
0.
found in 16dec12 Lynn baker email,
 survey results of other horns. (survey done 02nov12). Be careful with tiltx,tilty
tiltx is the angle from the xaxis to the tilt plane with positive moving in +z. This is actually a +rotation (CW)  about the y axis.
survey results of other horns (.pdf)
center of Curvature for  primary
x
feet
y
feet
z
feet
.01
-.02
883.125
center curvature for primary
coordSys: AO9 origin, x axis east, yaxis north, z up
From 2001 primary survey
lynn baker email 17jun2002
Radius of Curvature
869.883 feet
from 2001 primary survey
lynn baker email 17jun2002
Reflector to AO9
(dimple)
13.242 feet
subtracting above z value and radius above.
Paddles around dome pupil

see lynn baker email
26nov2001
AO9 offsets from platform bearing
x inches
east +
y inches
north positive
.2
2.2
using 09aug01 ao9 survey of dome
(more info)
ray trace origin in DCL
x
y
z
8' 5 1/4'
0
-12' 5"
from upgrade drawings. Also used in CRDDVN.M routine (xxold_laptop/math/
Before translating, the RTC coord should be rotated  by (asin(8.4375)/435.) -> 1.11141 deg about the y axis (cw pos).





More info: survey/lynnInfo


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