1 - NGA

individual major error sources with the quarrfifled
error or uncalainty which each contributes to a
total system accrsracy or probable error.
●rror ●queflo-The probability equation
wtrbzh expresses the laws 01 the occurrence of
random errors. This equation expresses the
relatbnship between obsemed values, PIUS fketorder
cxwredrnn terms, and theoretical vafues.
The error equatimt ie the basis of the method of
feast squares, used fn rhe adjustment o!
obeewalions for detarminirrQ lha most probable
vah.re of a resuft from those observations,
error lntervaf-Sea confldance interval.
error of cloeure-1. (general) The amount
by which a quanftty oMainetY by a serfes of
related measurements diffem from me true or
fixed value of tha same quanffly. Also called
clonlng error; closure. 2. (angles) The
arneum by which lhe actual aum 01 a series of
angles fails 10 equal the theoretically exact value
of that sum. Also called angular error of
cioeute. 3. (azimuth) The amount by which
two va!ues of the azimuth of a line, derived by
dtierent surveys or along ditferanl mutes, fail to
be exactly equal 10 each other. Also called
azimuth error of closure. 4. (leveling) The
amoum by which rwo vatues of the elevation of
the same bench mark, derived by difterem
surveys or through diflarent survay routes or by
independent observations, fail 10 be exacily
equal 10 each olher. Also called levellng error
01 cloaura. See alaa clrcult closure. 5.
~loop) The error In lhe closure of a swvay on
ttseff. Loops do nof pmtecf against systematic
errors in dietenw measurement or blunders in
starting posifbn or azimuth. Atao called foop
error of cloeure. 6. (horizon) The amoum by
which Ihe sum of a series of adjacent measured
horfzomal anglas around a point falls to equal
axactiy 360”. Meaauremarrf of the last angle of
the series Is called cioalng tha horizon; also
callad ctcxauro of horizon; horizon
closure. 7. (triangie) The amount by which the
sum of Ihe three observed angies of a lriangfe
falls to ecpal exactly 1SO” ptus the spherical
axcem of tha triangle. Atao callad closure of
triangie; triangfe cioeure; triangle error
of cfoaure. 8. (traverse) The amount by which
a value of the positkm of a traverse station, as
obtained by computation through a travarse,
fails to agree with another vatue of tha same
atatbn as determined by a different set of
observations or mu!ea of survey. Also calied
closure of traverse; error of survey;
horizontal cloeure error; travarse error
MIL-HDBK-850
87
of cloeure. See also Ilnaar error of
ctoaure; reiative error ot ciosure.
error of Collimation-See collimation
error.
error of Obaewatlon-The difference
between an obsewed value of a quamity and a
value adopted as representing the fdeai or true
vaiue of that quantity.
error of rurt-(micmmeter) The dfflerence, in
eeconds of arc, between the infemMd vaiue of
one tum of lhe micmmeter screw and ifs actual
value as determined by maasuring tha spaca
batwean two adjasant graduation ma~a of Ihe
circle with the micrometer. Aieo calied mn; mn
of micrometer.
error of survey-See error of ciosure,
cfetinition 8.
arror of the maan-See standard error of
the mean.
error—1. The difference between an obearved
or compuled vaiue of a quantify and Iha Idaai or
true value of that quarrtffy. 2. An errer is
genersliy ciasstfied as one of three types: (i) a
blunder (mistake) which can be identified and
corrected; (2) a systematic error, either constant
or variable, which must be compensated foc
and (3) a random error, one of the ctaas of small
inaccuracies due 10 imperfections in equipment,
surrounding condiiiona, or human fimifations.
See aieo rsbsoiute error; actual erro~
accumulative error; biunder;
chronometer error; Clrcult CIOSUrO;
circular error; circular error probable:
cfrcular near-cerfrxlnty error; circular
standard error; clamplng error;
collimation error; compass fndex error;
compensating error; constant ●rror;
curved-path srror; eccentric errori
erratic error; extarnal srrofi gnsdueflon
arror; gross error; Indax error; inherited
error; Instrument srror; iaw of
propagation of error; ilnear error; mean
square error: moduiaflon error: natural
arror; naar-cenafnty error; orthomefric
error; parallactfc error; periodic errors:
peraonaf error; pointing error; poslffonal
error; principabdlafance error; prlnclpalpolnt
error; prlsmafic error; probabie
error; random error; reslduel error;
resultant error; scafe error; shade error;
standard arror; ●yetemsflc error;
fheoretlcal error.