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optical landing system
velocities and other parameters of hardware or
phenomena.
optical landing system Refined form of mirror sight in
which gyrostabilized light beams indicate to approaching
pilot deviation from glidepath (USN, USMC).
optical line of sight LOS through atmosphere, which in
precision measures is not to be regarded as straight.
optical linescan Term used for various line-by-line scanning
at optical wavelengths, including RBV (video).
optically flat panel Window used in visual sighting
systems through which light passes with near-zero
distortion.
optical maser See laser.
optical Mems Mems operating at optical wavelengths.
optical pyrometer Instrument giving numerical readout
of temperature of hot surface by measuring incandescent
brightness.
optical reference point Index mark on canopy or elsewhere
providing pilot with sightline guidance in vertical
or near-vertical landing.
optical turbulence Fluctuating distortion of light rays
caused by time-varying gradients of refractive index.
optimal control model The most recent [1970] model of a
pilot [for example], based on the assumption that “a welltrained
well-motivated operator behaves in a
near-optimal manner, subject to his inherent limitations,
constraints and task.”
optimized profile Flight trajectory calculated to minimize
energy consumption throughout flight (but for
operational reasons seldom attainable).
optimum angle of attack That giving maximum L/D and
thus highest cruise efficiency.
optimum angle of glide That at which glide ratio is a
maximum.
optimum coupling Matched radio impedance in which
load equals output of amplifier or transmission line, for
maximum power transfer.
optimum height Height of air burst or conventional
explosion producing maximum effect against given target.
option 1 Acquisition of particular place in aircraft or
other major equipment item production programme, with
or without deposit and without agreement to purchase.
2 Variation in standard of product offering customer
choice, eg avionic fit, long-range tankage, de-icers etc.
3 Alternative decisions open to commander engaged in
battle.
optional, or optimal, yield management Determining
traffic mix by class code and fare type to maximize
revenue.
opto-electronic Combining optical and electronic
subsystems in single device; term appears to be used
synonymously with EO.
optronics Technology of systems using wavelengths
from optical to electronic. Appendix 4.
optrotheodolite Doubtful designation for precision
position-correlating instrument combining laser and
video camera.
OPU Overspeed protection unit.
Opute Operational utility evaluation (Pads, 4).
OPV Optionally [or operationally] piloted vehicle; some
of this class are helicopter UAVs.
OQAR Optical quick-access recorder.
OQPSK Offset quadrature phase-shift keyed, or
keying.
orbiter
OR 1 Operational research.
2 Operational requirement[s] (UK).
3 Operational readiness; also (1985) operationally
ready (DoD).
4 See OR gate.
5 Open rotor.
6 Other ranks.
7 On request.
8 Over-run lights.
9 Operational reliability.
O/R, o/r On request.
Oracle 1 Operational research and critical-link
evaluation.
2 Optical and RF combined-link experiment (USAF).
Orads Optical ranging and detecting systems (USA).
Oralloy Classified metal alloy, not necessarily based on
U-235, used as preferred primary fissile material in NW,
with or without tritium.
Orange Could be friendly or hostile, uncertain.
Orange Force Simulated hostile force during exercise
(NATO, IADB).
oranges Weather (RAF, WW2).
Oranges Sour Air-intercept code: weather unsuitable
for mission (DoD).
Oranges Sweet Air-intercept code: weather suitable for
mission (DoD).
Orasis Optical real-time adaptive spectral identification
system.
ORB, Orb 1 Operations record book (RAF).
2 Omnidirectional radio beacon.
orbat Order of battle.
orbit 1 Closed elliptical or quasi-circular path of body
revolving around source of gravitational attraction
balanced by its own centrifugal force.
2 Closed pattern, usually circular or racetrack,
followed repeatedly by aircraft, eg in air-intercept loiter
or when holding.
3 To follow an * as in (1) or (2).
orbit[al] decay Decay (1).
orbital elements See orbital parameters.
orbital manoeuvring vehicle Used from Shuttle and later
from space station to position and retrieve satellites about
1,000 miles distant (NASA).
orbital parameters Basic numerical values describing
orbit, such as apogee, perigee, inclination and period.
orbital period Time to complete one revolution (relative
to space, ignoring such irrelevancies as rotation of
primary body); symbol P, whose square is always proportional
to cube of semi-major axis of orbit (distance from
centre of primary to apogee).
orbital rendezvous See rendezvous.
orbital transfer vehicle 1 The first * was a reusable tug
shuttling between a planetary or lunar orbiter and higher
orbits.
2 Part of the planned MSP, a vehicle for orbit transfers
and servicing, potentially reducing spacecraft weight and
extending on-orbit life.
orbit determination Calculation of orbital parameters of
unknown satellite.
orbiter 1 Portion of spaceflight system designed to orbit,
as distinct from booster stages, tanks, etc.
2 In particular, bus to inspect planetary body from a
distance, with or without probes.
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