1.3 SCHED Input and Output Files
SCHED takes input from several types of files in addition to any interactive input. All of these files
can be separate, as long as SCHED can find them, or most of them can be imbedded in the main
input file. The former is more convenient. But, when the input file is to be sent somewhere else to be
run again, it may be safer to imbed the catalog information in the main file. All input to SCHED is in
the keyin free format section. This is the same format as is used by all Caltech VLBI package programs.
The input file types are:
-
Main Schedule Input File:
-
This
is
the
file
that
contains
the
details
of
the
particular
project.
It
can
have
the
most
of
the
other
files
imbedded
in
it.
This
file
must
be
created
by
the
user.
This
file
should
be
given
a
name
like
bv016.key
for
project
BV016.
See
the
/schedb
examples
for
numerous
samples.
-
Source Catalog:
-
These
files
contain
the
information
about
the
sources,
especially
names,
positions,
and,
for
line
sources,
velocities.
There
are
standard
source
catalogs,
although
the
user
may
need
to
add
non-standard
sources.
Source
catalog
entries
can
be
included
in
the
Main
Schedule
Input
File.
There
are
two
standard
source
catalogs
which
are
$SCHED/catalogs/sources.gsfc,
and
$SCHED/catalogs/sources.petrov,
which
contains
sources
respectively
from
from
the
Goddard
geodesy
group
and
from
Leonid
Petrov.
The
links
above
are
actually
to
symbolic
links
to
the
latest
catalog
from
each
source
as
of
the
time
of
the
SCHED release.
These
catalogs
contain
thousands
of
sources
(near
10,000
in
Petrov’s
case),
so
the
old
catalog
that
contained
a
few
sources
from
elsewhere
has
been
abandoned.
Two
external
catalogs
can
be
specified
if
one
wishes,
for
example,
to
use
the
standard
one
for
calibrators
and
another
for
multiple
phase
centers.
Please
note
that
this
source
catalog,
along
with
the
locations
catalog,
is
updated
approximately
annually.
It
cannot
be
relied
upon
to
maintain
constant
positions
for
a
multi-year
project.
If
you
need
constant
positions,
include
your
own
set
in
your
schedule.
Otherwise,
include
a
step
in
processing
that
accounts
for
changes
in
the
assumed
calibrator
position.
Note
that
the
Earth
orientation
and
station
locations
actually
change
with
time
(plate
tectonics
etc)
so
exact
repeats
of
the
observing
geometry
are
not
possible.
-
Station Catalog:
-
This
file
contains
information
about
the
antennas
including
names,
positions,
slew
limits,
horizons
etc.
There
is
a
standard
station
catalog
that
should
suffice
for
nearly
all
users.
If
not,
entries
can
be
included
in
the
Main
Schedule
Input
File.
Station
positions
may
stored
separately
in
the
Location
Catalog.
The
standard
station
catalog
is
$SCHED/catalogs/stations_RDBE.dat.
The
old
version
for
use
with
the
legacy
VLBA
systems
is
still
$SCHED/catalogs/stations.dat.
By
the
next
SCHED release,
it
is
likely
that
stations.dat
will
be
the
RDBE
version
and
the
legacy
version
will
be
renamed
or
removed.
-
Location Catalog:
-
This
file
contains
station
locations.
The
standard
version
reflects
the
locations
and
velocities
used
on
the
VLBA
correlator.
It
is
documented
along
with
the
Station
Catalog
because
they
are
tightly
coupled.
The
Locations
Catalog
is
optional
since
it
is
not
needed
if
the
station
locations
are
specified
in
the
Station
Catalog.
It
exists
separately
for
ease
of
maintenance.
The
standard
location
catalog
is
$SCHED/catalogs/locations.dat.
-
Setup Files:
-
These
files
contain
the
details
required
to
configure
the
hardware
at
the
stations.
Different
projects
using
the
same
hardware
configuration
can
use
the
same
setup
files.
There
are
many
standard
setup
files
are
located
in
$SCHED/setups.
-
Frequency Catalog:
-
This
file
contains
information
about
valid
frequency
setups
at
the
stations.
The
RF
ranges
that
can
be
covered
and
the
local
oscillator
and
polarization
of
each
IF
are
given.
SCHED can
use
this
information
to
provide
good
defaults
for
many
parameters
in
the
setup
files.
The
standard
file
should
be
used.
Any
non-standard
information
can
be
in
the
setup
files.
This
file
cannot
be
imbedded
in
the
main
input
file.
The
standard
frequency
catalog,
for
use
with
the
RDBE
systems,
is
$SCHED/catalogs/freq_RDBE.dat.
The
legacy
version
is
still
available.
It
is
$SCHED/catalogs/freq.dat
The
main
difference
is
that
the
VLBA
IFs
are
assumed
to
be
between
512
and
1024
MHz
in
the
RDBE
version,
not
500
and
1000
MHz
as
in
the
legacy
version.
By
the
next
SCHED release,
the
RDBE
version
will
likely
become
$SCHED/catalogs/freq.dat
and
the
legacy
version
will
be
renamed
or
removed.
-
Tape Initialization File:
-
This
file
tells
SCHED the
properties
of
the
tape
systems
at
the
stations
and
where
to
start
on
each
tape.
Since
tapes
are
no
longer
in
use,
this
file
is
mostly
obsolete.
However
it
can
be
used
to
specify
use
of
a
recording
system
at
a
station
that
is
different
from
what
is
given
as
the
default
in
the
station
catalog.
This
is
generally
only
useful
during
periods
when
stations
are
transitioning
between
different
recording
systems.
Note
that
many
old
files,
often
used
as
templates,
contain
tape
initialization
sections.
These
should
be
removed.
-
Reference Pointing Control File:
-
SCHED can
insert
scans
for
reference
pointing
at
high
frequencies
on
the
VLBA
and
VLA.
This
file
contains
information
needed
to
control
that
function.
It
will
only
be
of
interest
for
observations
above
15
GHz
on
the
VLA
and
at
86
GHz
on
the
VLBA.
The
standard
reference
pointing
control
file
is
at
$SCHED/catalogs/peak.cmd
There
is
a
special
version
related
to
reference
pointing
when
using
the
new
wideband
(RDBE/MARK5C)
system
on
the
VLBA.
It
is
$SCHED/catalogs/peak_RDBE.cmd.
-
Spectral Line Rest Frequencies:
-
SCHED can
adjust
the
observing
frequency
to
remove
the
Doppler
shifts
due
to
the
motions
of
the
Earth
around
the
Sun
and
to
the
Sun
with
respect
to
a
desired
reference
frame.
To
do
this,
SCHED needs
to
know
the
rest
frequency
of
the
line
being
observed.
This
is
given
in
a
lineinit
section
imbedded
either
in
the
main
file
or
in
the
reference
pointing
control
file.
There
is
a
file,
$SCHED/catalogs/linefreqs.dat,
distributed
with
SCHED,
that
gives
the
rest
frequencies
for
many
of
the
maser
lines
commonly
observed
with
VLBI.
-
Ephemeris file:
-
SCHED can
be
used
to
schedule
observations
of
planets.
To
do
so,
it
obtains
positions
from
a
JPL
ephemeris
file.
Mostly
this
is
used
for
single-dish
calibration
observations.
-
Satellite file:
-
SCHED can
also
be
used
to
schedule
observations
of
satellites.
To
do
so,
it
obtains
orbital
elements
from
the
SATFILE
or
TLEFILE
which
are
specified
in
the
SATINIT
section.
This
is
used
for
holography
and
for
spacecraft
navigation
projects.
Satellite
tracking
is
discussed
in
the
Satellite
tracking
section
SCHED processes the input files and creates several output files. Most follow a naming convention
that starts with the project code (bv016 will be used in the examples here) followed by a file type
indicator, then a period, then a two letter station code (pt for Pie Town in the examples below). The
experiment code is read by SCHED in the EXPCODE parameter in the main schedule input. The station
code comes from the station catalog and a list if given in Appendix A.1. The output files
are:
-
Summary File:
-
This
file
gives
a
rather
extensive
summary
of
the
setups
and
observations.
This
is
the
most
useful
output
file
for
the
user
as
it
shows
how
SCHED has
interpreted
the
input
commands.
The
file
will
be
called,
for
example,
bv016.sum.
The
items
displayed
for
each
scan
can
be
controlled
with
the
parameter
SUMITEM.
-
sched.runlog:
-
This
file
reflects
most
of
what
you
see
on
the
screen
when
SCHED is
running,
plus
may
contain
additional
messages
that
help
debug
problems
should
they
occur.
-
Operator Schedule Files:
-
These
files,
of
which
there
is
one
per
antenna,
give
much
more
information
about
the
schedule
than
can
be
included
in
the
summary
file
and
are
useful
when
that
level
of
detail
is
needed.
They
were
originally
meant
for
the
use
of
operators
of
manually
controlled
antennas,
but
now
most
antennas
are
computer
controlled
and
these
files
are
more
useful
for
the
scheduler.
The
files
are
named,
for
example,
bv016sch.pt.
-
VLBA type Antenna Control Files (crd files):
-
These
files
provide
the
legacy
on-line
control
systems
of
the
type
found
at
VLBA
antennas
with
the
information
they
need
to
control
the
observations.
There
is
one
file
per
antenna
that
uses
a
VLBA
control
computer
for
either
full
control
of
the
station
or
for
control
of
just
the
data
acquisition
system
(data
recorders,
baseband
converters
etc.).
The
files
are
named,
for
example,
bv016crd.pt.
Note
that
the
VLBA
antennas
currently
are
in
transition
with
some
items
controlled
by
the
legacy
system
and
some
by
the
new
control
system
which
is
commanded
using
the
VEX
file.
-
VEX file:
-
This
is
the
main
output
file
needed
by
the
stations
for
antenna
and
recording
system
control
and
by
the
correlators
to
process
observations.
It
is
now
used
by
most
VLBI
systems
around
the
world,
not
just
the
Goddard
“Field
System”.
For
the
VLBA,
it
is
used
to
control
the
RDBE,
MARK5C,
and
some
antenna
data
path
switches.
The
legacy
system,
commanded
by
the
crd
files
described
above,
still
controls
the
antenna
pointing
among
various
functions.
Both
are
needed.
A
single
VEX
file
describes
the
observations
for
all
antennas.
-
V2D file:
-
This
is
a
template
correlator
setup
file
for
the
(VLBA)
DiFX
correlator.
Information
that
needs
to
be
modified
from
what
is
in
the
VEX
file
can
be
specified
by
the
analysts
in
this
file.
It
is
also
the
path
to
transmit
information
about
multiple
phase
centers
per
pointing
to
the
correlator.
-
Flag file:
-
SCHED writes
a
file
with
the
.flag
extension
that
can
be
helpful
in
data
processing.
It
contains
flag
entries,
in
the
format
appropriate
for
the
AIPS
task
UVFLG,
that
cover
the
times
when
data
are
being
recorded,
but
the
antenna
is
expected
to
be
slewing.
For
the
VLBA,
the
monitor
flags
would
usually
take
care
of
such
times,
but
for
other
types
of
stations,
such
information
is
not
always
available
from
the
logs.
-
Preempt file:
-
Starting
in
Oct.
2011,
the
VLBA
will
be
providing
observations
of
up
to
1.5
hours
on
the
Pie
Town
to
Mauna
Kea
baseline
to
the
USNO
for
EOP
determination.
This
is
in
return
for
financial
support
for
operations.
These
observations
will
preempt
the
scheduled
project
on
the
two
stations.
There
is
some
flexibility
to
choose
the
exact
time
of
the
preemption
so
the
user
has
been
given
some
ability
to
guide
the
choice.
Important
scans
can
be
protected
using
the
PREEMPT
parameter.
Information
in
the
preempt
file,
which
is
also
in
the
summary
file,
is
used
by
operations
when
picking
the
time
for
the
EOP
observations.
-
Plots:
-
Sched
can
make
plots
of
u-v
coverage
and
of
various
combinations
of
azimuth,
elevation,
paralactic
angle,
hour
angle,
UT,
and
GST
against
each
other.
Plots
can
be
made
of
the
time
antennas
are
up.
Plots
can
be
made
of
beams.
The
plot
capability
can
be
used
to
plot
the
distribution
of
your
sources,
and
of
the
all
sources
in
the
catalog,
on
the
sky.
This
is
useful
for
looking
for
calibrators.
In
advanced
modes,
stations
can
be
moved
around
to
explore
UV
coverages
in
array
configuration
design
projects.
Also
quality
factors
can
be
calculated
and
plotted
with
contours
over
a
map
of
the
stations.
There
is
interactive
control
over
the
plotting,
the
only
interactive
part
of
SCHED.
Much
of
this
capability
is
mainly
useful
in
experiment
planning.
-
DiFX configuration file:
-
When
making
jobs
for
the
DiFX
correlator,
especially
as
used
for
the
VLBA,
a
.v2d
file
is
used
to
give
information
not
readily
deduced
from
the
.vex
file.
SCHED now
writes
a
template
for
that
file.
That
file
is
also
be
used
to
pass
lists
of
phase
centers
when
utilizing
the
DiFX
multiple
phase
center
capability.
-
Optimized Schedule:
-
When
one
of
SCHED’s
optimization
modes
is
turned
on,
or
geodetic
segments
are
requested,
the
program
writes
out
a
file,
such
as
bv016.sch
containing
the
basic
scan
inputs
for
a
new
main
schedule
file.
If
desired,
the
user
can
use
this
to
construct,
and
perhaps
modify,
a
new
optimized
main
schedule
input.
This
used
to
be
the
way
all
optimized
schedules
were
constructed,
but
now
that
SCHED fully
processes
an
optimized
schedule,
it
is
rarely
used
or
needed.
The
newer
use
is
to
make
it
easy
to
reproduce
geodetic
segments
when
something
else
is
changed
that
would
otherwise
change
the
results
of
the
optimization.
-
frequencies.list:
-
If
the
user
specifies
the
parameter
FREQLIST,
SCHED will
read
the
frequency
catalog
and
make
a
table
of
all
known
setups
which
can
be
used
to
make
observations
in
the
specified
frequency
range.
Then
SCHED will
quit
without
doing
further
processing.
This
is
useful
for
planning
and
for
information
while
making
setup
files.