1 - NGA

control; tmvorso.
ground data-see ground truth.
ground dlatarrca-The grea!drsb dtiance
bdween fwe gmtmd pdfiirss, as oorrtmafad
with ti ranger the afraigfrt.%te d=farrce
between two points. A& sefled ground
rang..
MIL-HDBK-850
ground @rrad forward (GGF)-(eeriel
phdogmphy) The nel gain per phoiogreph in
IIledirecfic lnefmgh fforaq%rclfie dovertep. The
GGFkeuaed frrsonpufe ffrerxsrrtmrrof
expoaure=3 In a aft@ of aerial phmgmphy.
ground galrrod .Idawaya (QGS)- (aerial
photography) The net IrAerel pin par tliihf fcf a
apesifii aidebp. The GGS b used 10 sornpme
the rrurrber of flight Iii- for an arm to be
photographed.
ground Irrtormatlon-sae ground truth.
ground nsdlr-(JCS) The point on the ground
verficeffy bermelh the perepesfiie senfer of the
camera lens, On e true verkai phc.togreph ths
coinddee wkh the prfnci@ point. Atso celled
ground plumb point.
ground pw’alld-The intersection of the
pksne of the photograph with the plane of
refemmce of the ground. See also axis of
homology.
ground photogrammetry-See terrtsatrlal
photogrammotry.
ground photograph-See tormatrfel
photograph,
ground plmra-The horisonfal plene paeaing
through the ground nadir of a camera station.
ground plumb point-See ground rradlr.
ground pyramid-A rnmponerrt of an
andyiicaf method for determining the pr-iae
degree of photographic tilt, representing e
epedk apelkl oorrfigumtian from three ground
scmfml pdrds (forming a triengle) on the ground
to the @q%raure etafiin of the phonograph
cmfainirrg the identical points. When used with
the photo pyramid, the ground pyremid permits
the axecf arrafyiical dafermkratti c4 tiil In the
photograph. See aleo photo pymmld.
114
ground ranga-See ground diatanao.
ground mBolutloKThs mirimurn diatmrce
which sen be defeded Mweem two edjacarrf
k+aturas, or the rrsinirrwrn size of a feature
axpmaad insizeot c@jeordisfMaes ontfte
ground.
ground mturrr-(JCS) The raffection from the
terrain as diiyed arder mmrdad 65 an
irmge.
ground qmd+fCS) The herknfal
cOMpOnMt cd the sfmad d an aircraft relative to
the aarfh’a utriese.
ground ●tatlon-A monumented atatiom:
eeteblbfd by fiifd eurvey mathode, wtiih IS
U* as a baas for ground station equipment for
the procurement of shoren or ehiran contmliad
photography or control defa.
ground ●mvey-A eurvey made by ground
methods, ae distinguished fmm an eeriel eurvey.
A ground eurvey may or may nd irrslude the
uea of Photographs.
ground swing-An error-causing sorrdidion in
electronic dietarroe meesuring whii is brought
about by the reffadion of the microwave baem
from the ground or water surface. The reflected
beam mixes with ha direct beam et the
reseiving antenna, thereby changing the pheee
of the d!recf beam and causing an error in the
diefarrce rnaesured. By varying the carrier
frequensy, the war bewrnes Syclic, rmking
poeeible mean inelrument reedinga thet ere
subatanfiilly accurate.
ground trec*See ground parsilol.
ground track-The vertical projectbn of the
flight prfh omo the surfas.a of Wre aerfh.
ground trrsth-A ferm coined for
dattikrformetion obtained frum actual ground
rneaeurement of euriaodshurfase feeturoe 10
aid in the interpretation of rerrrofefy eenaerf
data. Afeo called ground data; ground
information.
ground-sp=co coordlnato ●yatmn-A
scheme by which Fostions of tnangulafion
stalks, confrd poirrta, and other ground
featume are raleted by diefwrse end azimuth or
by x. and y-cwrdinetes.