1 - NGA

I
I
least altitude.
.— ..— .—. .——_ _
IJPPr MOtb~6WVeYbg) Rotation of the
upper *M 0/ a repasting ~.
war tinah-Tranti d a cdtdd ~ ~w
the ippar brench of ths celrdal meridiin. Also
celled cmtpartor transit. See also
culmination,
uaar httaflaca-Ths method by wlich the
human qaamtcx mmmunidns with the vWiOuS
dste base and appliibrra modules.
user raqulramant ●mlysls (URA)-The
study of the needs C4 ths polerrtisl system
Uaara.
UTO tfme-Tfre mesn universal time ~
frem otmewetii ol Iims ot eisr transils. Sinca
tha directions CAthe maridismr chsnge with tima
b-usa of the motion c4 the pole, the IJTO time
will, thus, be affected and N, thamfora, ba
Irrsgutsr. See also UT1 tlma; UT2 tlma.
UT1 tlms-l%e true angulsr rotation of the
Emth about its instantaneous spin sscis in the
mean ~untorisl 6y61em of dstas. UTl is
cbtsirrsd fmm Lrro by 00r1adii UTo f’w the
dfierence between the instsrrtsrreous and
maen kmgttude e! the obsawing station, Sines
LITI is keyed ~ to the instmda-s
mtden ef the Esrth, wlii is not sttitly uniform,
UTI does not ~- urdicimly. Saa also UTO
time; UT2 tlms.
UT2 tlma-llre mean angulsr motion ot the
Esrth, treed of pmdHtb& periodic vtui.don bul
still affected by bregular vatiatii and aeculsr
varMerra. UT2 la cbtgin.art b UTI ~
cOrmdng u—rlfor Maaaral vartstions in rcddii
rote. Sae elso UTO tlma; UTl tlma;
unlvoraal tlmo coordlrmted.
MIL-HDBK-850
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