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g!rwd steka+surwying) A stake dtiven near
n hh, ueuafty eloped with the @ of the QUSrd
-ka over the hltr. The guard stake protxls,
and Ba merf@p identify, the hub. .
gulda marldian-An auslfiery governing line
PrOiecfed north afong an aatmnornic meridii,
fmm fminta esfabfiied on the base lie or a
sterderd paraibl, usuelfy at krtervels d 24 rnk
east or west of the princ!pal meridian, on whkh
tovmahip, aaction, and qumler aecfion eomam
are esfabliched. See also ●uxiliary guide
meridian; prlnetpal marldlan.
guld~ drafting or aoribing surface beering a
map frrwge to be tnaxtd by drafthg or scribing
for repmduckn. Also celled color ●operation
guida; drafting guldo; scribing guide.
Gunta~a chain-A measuring device used in
land suweying, oorrposad of 100 metal links
fastened together with rings, the length cd Ihe
chain being 66 feet. Alao called four-pole
chain; tour-rod chain. See else chsln.
gyroazlmuth theodollta-See gyrotfloodollto.
gyrooompaus-A compa6s whiih functions by
virlue d the co@as genersted in e retor when
ths latter’s esie is displaced from parallelism with
that of the Eerfh. A gyrocornps= is
independent of megnetiem and *II
eulcwneticefty align itseff in the celestial matiten.
However, it requires e sfesdy tmurca of motiie
power and is subject to dynamic error under
certein conditions. Certain aircdt corrpesses
alse u gpsoo@s to gain Sfabitii, while
ralyhg besiilty on the tmgnatic meridian:
theaa are to be distinguished from lhe hue
gyrocompass.
gyromagnatlc compe8s-(JCS) A directional
9Y~ whose az”mufh scale is M“nfained
iii atigntit whh the magnetic meridisn by a
megnefic detector unit.
gyromorldlan Indicating instrument-See
gyrothoodolito.
gyroscopa-A device consisting of e spinning
rolor and as.sAetad supporting readouts whiih
mskas use d Newion’a hw of Roiation 10 give
an indkdion of the errgufar velocii of the.
instrumanra case with r- to an inertial
reference frame. Thie instrument ie used as the
basic aaneor in many direct’kn%aaking,
MIL-HDBK-E150
115
duectii-keepirrg, and etfifude stabilization
ay6tems.
gyroacoplc ●ablllxetlon-Equilibrium in the
attitude ancVor oouraa of e shii or airborne
vehicle rnaintaind by the usa of gymecopes.
Atao, the maintenance (bytheuseof
gymecopes) of .s samare in a desired aftkrde
*n an eirbema vehiile.
gyrothacrdoiita-A heurieiiie with e
gymmqxm attached or buitf in, whereby a
true azimuth rdersnce can be aetabkhsd in
any Waether, day or night, without the aid&
Stars, Iw-ldrrmrks, er other ViaiMe stations. The
az”muth obtained fmm the gyro w hwrtiai
theodofiie ie assantieity the astronomic az”nuth
at the point of observation. This azimuth will
dfler from the corresponding geodetic ezimufh
by the emount of the Laplece cerractiwi.