AIPS HELP file for UVFIXPRM in 31DEC20
As of Wed Jun 3 1:10:00 2020
Type: Adverb (Real(20))
Use: The task specific parameters for UVFIX. Specifies
geometry and time information.
Null value: Usually 0.
UVFIX Recomputes u, v, and w with optional tangent point
1 => array type, 0=VLA, 1=VLBI, 2=other.
2 => array number, 0 => loop over all.
3+4 => array BX, meters. (proper defaults for UVFIXPRM(1)=
5+6 => array BY, meters. 0 or 1)
7+8 => array BZ, meters.
Here X is in the direction of the intersection of the
meridian of the reference location (long=0 for earth
centered) and the equator; Y is 90 deg. EAST along the
equator from X; Z is in the direction of the N. pole.
BX = UVFIXPRM(3) + UVFIXPRM(4),
BY = UVFIXPRM(5) + UVFIXPRM(6),
BZ = UVFIXPRM(7) + UVFIXPRM(8).
The addition of two parameters allows the coordinates
to be specified with more precision than a single adverb
allows; on a 32-bit machines adverb values are only
accurate to 7 significant digits.
11 => UT1-UTC in seconds, no default.
12 => IAT-UTC in seconds, default = year-1961 which is OK
until mid-1982 when after which it is off 1 (or more)
second(s). Accurate values for both UT1-UTC and
IAT-UTC can be obtained from USNO Bulletin no. 7.
13 => Clock error. This is mostly used for VLA data for
which the time labels are in error by half of the
MODCOMP online averaging time. Usually 5 seconds.
(no default). The clock error is subtracted from
times in the file.
14 => Frequency in Hz. If .LE.0 the value in the AN file
will be used.