1 - NGA

navigation chari-See aeronautical
chart; hydrographlc chart.
Sravlgallon alghi—An auxiliary device used
in the Iaking of aerial photography to show
nol only the vertical Iiekf of view buf also
the path ahead and behind the aircraft.
Navlgatlonal Flhmstrlps (NFS)—Filmstrips
depicting cartographic data as
photographed from lithographic copy
arrwng the JNC and TPC series for A-7
aircraft, ONC and JOG series for HH-53
aimraff. and all 4 chart series for Remoie
Map Reader (RMR) equipped (F-14 E).
Used In akcraft equipped wi!h a moving
map display system to provide in-cockpit
display of aircrafl horizontal position relative
to the chart data.
navigational planets—The tour planels
commonly used ior celestial navigation:
Venus, Mars, Jupiter, and Salurn.
nsvlgarlonal triangle—The spherical
triangle solved in compuling altitude and
azimuth or greal circle sailing problems.
The celestial triangle is Iormed on the
celestial sphere by the great circles
connecting the elevated pole, zenilh of the
assumed position of Ihe observer, and a
celestial body. The iarrastrial triangle is
formed on a spherical Earth by the great
circles connecting the pole and two places
on Earth, either the assumed position of
the obsamer and geographic position of the
body for calastial observations, or the
points of deparlure and declination for
great circle sailing problems. The
expression navigational lrtangle
aPPlies to either the celestial or terrestrial
trlangte used for solving navigation
problems.
NAVINFONET—See Navlga!lon
Informssllon Network.
NAVSTAR Globat Poaltlortlng System
(GPS)—A navigation and positioning
system, mnsisling of 24 saleltites, with
which Ihe three-dimensional position and
the velaclty of a user at a poinl on or near
tha Earlh can be determined in real lime.
Its raterance syslem ia WGS 84. The
users receiver will require tracking of a
minimum of four of the salelli!es trom any
tocation at any time to eslabtish position
MIL-HDBK-850
169
anct velocity.
Navy Navlgatlon Satellite System
(NNSS)—A set 01 tive or six saleltites in
polar otitl with which three-dimensisnat
position of a user can be determined. See
also brosdcast aphamarls; Dopplar
navlgatlon; praclae ephemarta.
near-certainty error (3.5 elgma, 3.5u)—
The 99.76 percent error kderval based on
the bivariate normal distribution function.
See also circular near-cartalnty error;
circutar error probable.
neat model—The portion of the gross
overtap of a pair of phonographs that is
actually utilized in photogrsmme!ric
procedures. Generally, tha neat model
aPPnJximaleS a rectangte whosa width
equals the air base and whose tength
equats the width between tlights. SeO atso
gross model.
neatllnes—(JCS) The lines that bound the
body 0! a map, usually parallets and
meridians [but may be conventional or
arbitrary grid lines]. Also catled shaet
Ilnes.
negative altltude—Angular distanca below
the horizon.
negative component In color mlxtura—
A componenl that is mixed wilh the sample
light in order to desaturate it sufficiently to
obtain a match with a mixture of the other
two components.
negetiva corrections—Changes mada
directly on a negative or a scribed surface.
See also negative engraving.
negative dellactlon angle—See
detlectlon sngle, definition 1.
negetlva engraving—The operation of
making corrections and additions to
negatives. This term shoutd not be applied
to the process 01 scribing on coaled
plastics,
negativa forming—in relief model making,
Iorming into a negalive motd,
negatlvs lens—A lens diverging a beam ot
parallel tigh! rays, with no raal focus being