<s>
A	O
head-up	B-Application
display	I-Application
,	O
or	O
heads-up	B-Application
display	I-Application
,	O
also	O
known	O
as	O
a	O
HUD	B-Application
(	O
)	O
or	O
Head-up	B-Application
Guidance	I-Application
System	I-Application
(	O
HGS	O
)	O
,	O
is	O
any	O
transparent	B-Device
display	I-Device
that	O
presents	O
data	O
without	O
requiring	O
users	O
to	O
look	O
away	O
from	O
their	O
usual	O
viewpoints	O
.	O
</s>
<s>
A	O
HUD	B-Application
also	O
has	O
the	O
advantage	O
that	O
the	O
pilot	O
's	O
eyes	O
do	O
not	O
need	O
to	O
refocus	O
to	O
view	O
the	O
outside	O
after	O
looking	O
at	O
the	O
optically	O
nearer	O
instruments	O
.	O
</s>
<s>
Although	O
they	O
were	O
initially	O
developed	O
for	O
military	O
aviation	O
,	O
HUDs	B-Application
are	O
now	O
used	O
in	O
commercial	O
aircraft	O
,	O
automobiles	O
,	O
and	O
other	O
(	O
mostly	O
professional	O
)	O
applications	O
.	O
</s>
<s>
Head-up	B-Application
displays	I-Application
were	O
a	O
precursor	O
technology	O
to	O
augmented	B-General_Concept
reality	I-General_Concept
(	O
AR	B-General_Concept
)	O
,	O
incorporating	O
a	O
subset	O
of	O
the	O
features	O
needed	O
for	O
the	O
full	O
AR	B-General_Concept
experience	O
,	O
but	O
lacking	O
the	O
necessary	O
registration	O
and	O
tracking	O
between	O
the	O
virtual	O
content	O
and	O
the	O
user	O
's	O
real-world	O
environment	O
.	O
</s>
<s>
A	O
typical	O
HUD	B-Application
contains	O
three	O
primary	O
components	O
:	O
a	O
projector	O
unit	O
,	O
a	O
combiner	O
,	O
and	O
a	O
video	O
generation	O
computer	O
.	O
</s>
<s>
The	O
projection	O
unit	O
in	O
a	O
typical	O
HUD	B-Application
is	O
an	O
optical	O
collimator	O
setup	O
:	O
a	O
convex	O
lens	O
or	O
concave	O
mirror	O
with	O
a	O
cathode-ray	B-Device
tube	I-Device
,	O
light	O
emitting	O
diode	O
display	O
,	O
or	O
liquid	B-Device
crystal	I-Device
display	I-Device
at	O
its	O
focus	O
.	O
</s>
<s>
the	O
focal	O
point	O
is	O
perceived	O
to	O
be	O
at	O
infinity	B-Application
.	O
</s>
<s>
The	O
combiner	O
is	O
typically	O
an	O
angled	O
flat	O
piece	O
of	O
glass	O
(	O
a	O
beam	O
splitter	O
)	O
located	O
directly	O
in	O
front	O
of	O
the	O
viewer	O
,	O
that	O
redirects	O
the	O
projected	O
image	O
from	O
projector	O
in	O
such	O
a	O
way	O
as	O
to	O
see	O
the	O
field	O
of	O
view	O
and	O
the	O
projected	O
infinity	B-Application
image	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
The	O
computer	O
provides	O
the	O
interface	O
between	O
the	O
HUD	B-Application
(	O
i.e.	O
</s>
<s>
Other	O
than	O
fixed	O
mounted	O
HUD	B-Application
,	O
there	O
are	O
also	O
head-mounted	B-General_Concept
displays	I-General_Concept
(	O
HMDs	O
)	O
.	O
</s>
<s>
These	O
include	O
helmet-mounted	B-Application
displays	I-Application
(	O
both	O
abbreviated	O
HMD	O
)	O
,	O
forms	O
of	O
HUD	B-Application
that	O
feature	O
a	O
display	O
element	O
that	O
moves	O
with	O
the	O
orientation	O
of	O
the	O
user	O
's	O
head	O
.	O
</s>
<s>
Many	O
modern	O
fighters	O
(	O
such	O
as	O
the	O
F/A	B-Application
-18	I-Application
,	O
F-16	O
,	O
and	O
Eurofighter	O
)	O
use	O
both	O
a	O
HUD	B-Application
and	O
HMD	O
concurrently	O
.	O
</s>
<s>
The	O
F-35	O
Lightning	O
II	O
was	O
designed	O
without	O
a	O
HUD	B-Application
,	O
relying	O
solely	O
on	O
the	O
HMD	O
,	O
making	O
it	O
the	O
first	O
modern	O
military	O
fighter	O
not	O
to	O
have	O
a	O
fixed	O
HUD	B-Application
.	O
</s>
<s>
HUDs	B-Application
are	O
split	O
into	O
four	O
generations	O
reflecting	O
the	O
technology	O
used	O
to	O
generate	O
the	O
images	O
.	O
</s>
<s>
First	O
Generation	O
—	O
Use	O
a	O
CRT	B-Device
to	O
generate	O
an	O
image	O
on	O
a	O
phosphor	O
screen	O
,	O
having	O
the	O
disadvantage	O
of	O
the	O
phosphor	O
screen	O
coating	O
degrading	O
over	O
time	O
.	O
</s>
<s>
The	O
majority	O
of	O
HUDs	B-Application
in	O
operation	O
today	O
are	O
of	O
this	O
type	O
.	O
</s>
<s>
Second	O
Generation	O
—	O
Use	O
a	O
solid	O
state	O
light	O
source	O
,	O
for	O
example	O
LED	O
,	O
which	O
is	O
modulated	O
by	O
an	O
LCD	B-Device
screen	I-Device
to	O
display	O
an	O
image	O
.	O
</s>
<s>
Newer	O
micro-display	O
imaging	O
technologies	O
are	O
being	O
introduced	O
,	O
including	O
liquid	B-Device
crystal	I-Device
display	I-Device
(	O
LCD	B-Device
)	O
,	O
liquid	B-Device
crystal	I-Device
on	I-Device
silicon	I-Device
(	O
LCoS	B-Device
)	O
,	O
digital	B-General_Concept
micro-mirrors	I-General_Concept
(	O
DMD	O
)	O
,	O
and	O
organic	B-Device
light-emitting	I-Device
diode	I-Device
(	O
OLED	B-Device
)	O
.	O
</s>
<s>
HUDs	B-Application
evolved	O
from	O
the	O
reflector	O
sight	O
,	O
a	O
pre-World	O
War	O
II	O
parallax-free	O
optical	O
sight	O
technology	O
for	O
military	O
fighter	O
aircraft	O
.	O
</s>
<s>
During	O
the	O
early	O
1940s	O
,	O
the	O
Telecommunications	O
Research	O
Establishment	O
(	O
TRE	O
)	O
,	O
in	O
charge	O
of	O
UK	O
radar	B-Application
development	O
,	O
found	O
that	O
Royal	O
Air	O
Force	O
(	O
RAF	O
)	O
night	O
fighter	O
pilots	O
were	O
having	O
a	O
hard	O
time	O
reacting	O
to	O
the	O
verbal	O
instruction	O
of	O
the	O
radar	B-Application
operator	O
as	O
they	O
approached	O
their	O
targets	O
.	O
</s>
<s>
They	O
experimented	O
with	O
the	O
addition	O
of	O
a	O
second	O
radar	B-Application
display	O
for	O
the	O
pilot	O
,	O
but	O
found	O
they	O
had	O
trouble	O
looking	O
up	O
from	O
the	O
lit	O
screen	O
into	O
the	O
dark	O
sky	O
in	O
order	O
to	O
find	O
the	O
target	O
.	O
</s>
<s>
In	O
October	O
1942	O
they	O
had	O
successfully	O
combined	O
the	O
image	O
from	O
the	O
radar	B-Application
tube	O
with	O
a	O
projection	O
from	O
their	O
standard	O
GGS	O
Mk	O
.	O
</s>
<s>
IV	O
radar	B-Application
to	O
the	O
microwave-frequency	O
AI	O
Mk	O
.	O
</s>
<s>
VIII	O
radar	B-Application
found	O
on	O
the	O
de	O
Havilland	O
Mosquito	O
night	O
fighter	O
.	O
</s>
<s>
In	O
1955	O
the	O
US	O
Navy	O
's	O
Office	O
of	O
Naval	O
Research	O
and	O
Development	O
did	O
some	O
research	O
with	O
a	O
mockup	O
HUD	B-Application
concept	O
unit	O
along	O
with	O
a	O
sidestick	O
controller	O
in	O
an	O
attempt	O
to	O
ease	O
the	O
pilot	O
's	O
burden	O
flying	O
modern	O
jet	O
aircraft	O
and	O
make	O
the	O
instrumentation	O
less	O
complicated	O
during	O
flight	O
.	O
</s>
<s>
While	O
their	O
research	O
was	O
never	O
incorporated	O
in	O
any	O
aircraft	O
of	O
that	O
time	O
,	O
the	O
crude	O
HUD	B-Application
mockup	O
they	O
built	O
had	O
all	O
the	O
features	O
of	O
today	O
's	O
modern	O
HUD	B-Application
units	O
.	O
</s>
<s>
HUD	B-Application
technology	O
was	O
next	O
advanced	O
by	O
the	O
Royal	O
Navy	O
in	O
the	O
Buccaneer	O
,	O
the	O
prototype	O
of	O
which	O
first	O
flew	O
on	O
1958	O
.	O
</s>
<s>
The	O
aircraft	O
was	O
designed	O
to	O
fly	O
at	O
very	O
low	O
altitudes	B-Application
at	O
very	O
high	O
speeds	O
and	O
drop	O
bombs	O
in	O
engagements	O
lasting	O
seconds	O
.	O
</s>
<s>
This	O
led	O
to	O
the	O
concept	O
of	O
a	O
"	O
Strike	O
Sight	O
"	O
that	O
would	O
combine	O
altitude	B-Application
,	O
airspeed	O
and	O
the	O
gun/bombsight	O
into	O
a	O
single	O
gunsight-like	O
display	O
.	O
</s>
<s>
There	O
was	O
fierce	O
competition	O
between	O
supporters	O
of	O
the	O
new	O
HUD	B-Application
design	O
and	O
supporters	O
of	O
the	O
old	O
electro-mechanical	O
gunsight	O
,	O
with	O
the	O
HUD	B-Application
being	O
described	O
as	O
a	O
radical	O
,	O
even	O
foolhardy	O
option	O
.	O
</s>
<s>
The	O
Cintel	O
HUD	B-Application
business	O
was	O
taken	O
over	O
by	O
Elliott	O
Flight	O
Automation	O
and	O
the	O
Buccaneer	O
HUD	B-Application
was	O
manufactured	O
and	O
further	O
developed	O
,	O
continuing	O
up	O
to	O
a	O
MarkIII	O
version	O
with	O
a	O
total	O
of	O
375	O
systems	O
made	O
;	O
it	O
was	O
given	O
a	O
'	O
fit	O
and	O
forget	O
 '	O
title	O
by	O
the	O
Royal	O
Navy	O
and	O
it	O
was	O
still	O
in	O
service	O
nearly	O
25	O
years	O
later	O
.	O
</s>
<s>
BAE	O
Systems	O
,	O
as	O
the	O
successor	O
to	O
Elliotts	O
via	O
GEC-Marconi	O
Avionics	O
,	O
thus	O
has	O
a	O
claim	O
to	O
the	O
world	O
's	O
first	O
head-up	B-Application
display	I-Application
in	O
operational	O
service	O
.	O
</s>
<s>
A	O
similar	O
version	O
that	O
replaced	O
the	O
bombing	O
modes	O
with	O
missile-attack	O
modes	O
was	O
part	O
of	O
the	O
AIRPASS	O
HUD	B-Application
fitted	O
to	O
the	O
English	O
Electric	O
Lightning	O
from	O
1959	O
.	O
</s>
<s>
At	O
this	O
point	O
,	O
the	O
HUD	B-Application
expanded	O
its	O
purpose	O
beyond	O
weapon	O
aiming	O
to	O
general	O
piloting	O
.	O
</s>
<s>
In	O
the	O
1960s	O
,	O
French	O
test-pilot	O
Gilbert	O
Klopfstein	O
created	O
the	O
first	O
modern	O
HUD	B-Application
and	O
a	O
standardized	O
system	O
of	O
HUD	B-Application
symbols	O
so	O
that	O
pilots	O
would	O
only	O
have	O
to	O
learn	O
one	O
system	O
and	O
could	O
more	O
easily	O
transition	O
between	O
aircraft	O
.	O
</s>
<s>
The	O
modern	O
HUD	B-Application
used	O
in	O
instrument	O
flight	O
rules	O
approaches	O
to	O
landing	O
was	O
developed	O
in	O
1975	O
.	O
</s>
<s>
Klopfstein	O
pioneered	O
HUD	B-Application
technology	O
in	O
military	O
fighter	O
jets	O
and	O
helicopters	B-Application
,	O
aiming	O
to	O
centralize	O
critical	O
flight	O
data	O
within	O
the	O
pilot	O
's	O
field	O
of	O
vision	O
.	O
</s>
<s>
Use	O
of	O
HUDs	B-Application
then	O
expanded	O
beyond	O
military	O
aircraft	O
.	O
</s>
<s>
In	O
the	O
1970s	O
,	O
the	O
HUD	B-Application
was	O
introduced	O
to	O
commercial	O
aviation	O
,	O
and	O
in	O
1988	O
,	O
the	O
Oldsmobile	O
Cutlass	O
Supreme	O
became	O
the	O
first	O
production	O
car	O
with	O
a	O
head-up	B-Application
display	I-Application
.	O
</s>
<s>
Until	O
a	O
few	O
years	O
ago	O
,	O
the	O
Embraer	O
190	O
,	O
Saab	O
2000	O
,	O
Boeing	O
727	O
,	O
and	O
Boeing	O
737	O
Classic	O
(	O
737-300/400/500	O
)	O
and	O
Next	O
Generation	O
aircraft	O
(	O
737-600/700/800/900	O
series	O
)	O
were	O
the	O
only	O
commercial	O
passenger	O
aircraft	O
available	O
with	O
HUDs	B-Application
.	O
</s>
<s>
HUDs	B-Application
have	O
become	O
standard	O
equipment	O
on	O
the	O
Boeing	O
787	O
.	O
</s>
<s>
Furthermore	O
,	O
the	O
Airbus	O
A320	O
,	O
A330	O
,	O
A340	O
and	O
A380	O
families	O
are	O
currently	O
undergoing	O
the	O
certification	O
process	O
for	O
a	O
HUD	B-Application
.	O
</s>
<s>
HUDs	B-Application
were	O
also	O
added	O
to	O
the	O
Space	O
Shuttle	O
orbiter	O
.	O
</s>
<s>
There	O
are	O
several	O
factors	O
that	O
interplay	O
in	O
the	O
design	O
of	O
a	O
HUD	B-Application
:	O
</s>
<s>
For	O
aviation	O
applications	O
,	O
the	O
major	O
benefit	O
of	O
a	O
wide	O
FOV	O
is	O
that	O
an	O
aircraft	O
approaching	O
the	O
runway	O
in	O
a	O
crosswind	O
might	O
still	O
have	O
the	O
runway	O
in	O
view	O
through	O
the	O
combiner	O
,	O
even	O
though	O
the	O
aircraft	O
is	O
pointed	O
well	O
away	O
from	O
the	O
runway	O
threshold	O
;	O
whereas	O
with	O
a	O
narrow	O
FOV	O
the	O
runway	O
would	O
be	O
'	O
off	O
the	O
edge	O
 '	O
of	O
the	O
combiner	O
,	O
out	O
of	O
the	O
HUD	B-Application
's	O
view	O
.	O
</s>
<s>
The	O
HUD	B-Application
image	O
is	O
viewable	O
by	O
one	O
or	O
both	O
eyes	O
,	O
depending	O
on	O
technical	O
and	O
budget	O
limitations	O
in	O
the	O
design	O
process	O
.	O
</s>
<s>
Because	O
the	O
light	O
rays	O
are	O
parallel	O
the	O
lens	O
of	O
the	O
human	O
eye	O
focuses	O
on	O
infinity	B-Application
to	O
get	O
a	O
clear	O
image	O
.	O
</s>
<s>
Collimated	O
images	O
on	O
the	O
HUD	B-Application
combiner	O
are	O
perceived	O
as	O
existing	O
at	O
or	O
near	O
optical	O
infinity	B-Application
.	O
</s>
<s>
This	O
means	O
that	O
the	O
pilot	O
's	O
eyes	O
do	O
not	O
need	O
to	O
refocus	O
to	O
view	O
the	O
outside	O
world	O
and	O
the	O
HUD	B-Application
display	O
–	O
the	O
image	O
appears	O
to	O
be	O
"	O
out	O
there	O
"	O
,	O
overlaying	O
the	O
outside	O
world	O
.	O
</s>
<s>
This	O
feature	O
is	O
critical	O
for	O
effective	O
HUDs	B-Application
:	O
not	O
having	O
to	O
refocus	O
between	O
HUD-displayed	O
symbolic	O
information	O
and	O
the	O
outside	O
world	O
onto	O
which	O
that	O
information	O
is	O
overlaid	O
is	O
one	O
of	O
the	O
main	O
advantages	O
of	O
collimated	O
HUDs	B-Application
.	O
</s>
<s>
It	O
gives	O
HUDs	B-Application
special	O
consideration	O
in	O
safety-critical	O
and	O
time-critical	O
manoeuvres	O
,	O
when	O
the	O
few	O
seconds	O
a	O
pilot	O
needs	O
in	O
order	O
to	O
re-focus	O
inside	O
the	O
cockpit	O
,	O
and	O
then	O
back	O
outside	O
,	O
are	O
very	O
critical	O
:	O
for	O
example	O
,	O
in	O
the	O
final	O
stages	O
of	O
landing	O
.	O
</s>
<s>
Collimation	O
is	O
therefore	O
a	O
primary	O
distinguishing	O
feature	O
of	O
high-performance	O
HUDs	B-Application
and	O
differentiates	O
them	O
from	O
consumer-quality	O
systems	O
that	O
,	O
for	O
example	O
,	O
simply	O
reflect	O
uncollimated	O
information	O
off	O
a	O
car	O
's	O
windshield	O
(	O
causing	O
drivers	O
to	O
refocus	O
and	O
shift	O
attention	O
from	O
the	O
road	O
ahead	O
)	O
.	O
</s>
<s>
Modern	O
HUD	B-Application
eyeboxes	O
are	O
usually	O
about	O
5	O
lateral	O
by	O
3	O
vertical	O
by	O
6	O
longitudinal	O
inches	O
(	O
13x8x15	O
cm	O
)	O
.	O
</s>
<s>
Boresight	O
–	O
Aircraft	O
HUD	B-Application
components	O
are	O
very	O
accurately	O
aligned	O
with	O
the	O
aircraft	O
's	O
three	O
axes	O
–	O
a	O
process	O
called	O
boresighting	O
–	O
so	O
that	O
displayed	O
data	O
conforms	O
to	O
reality	O
typically	O
with	O
an	O
accuracy	O
of	O
±	O
7.0milliradians	O
( ±24minutes	O
of	O
arc	O
)	O
,	O
and	O
may	O
vary	O
across	O
the	O
HUD	B-Application
's	O
FOV	O
.	O
</s>
<s>
For	O
example	O
,	O
objects	O
(	O
such	O
as	O
a	O
runway	O
threshold	O
)	O
that	O
are	O
3	O
degrees	O
below	O
the	O
horizon	O
as	O
viewed	O
from	O
the	O
cockpit	O
must	O
appear	O
at	O
the	O
−3	O
degree	O
index	O
on	O
the	O
HUD	B-Application
display	O
.	O
</s>
<s>
Compatibility	O
–	O
HUD	B-Application
components	O
are	O
designed	O
to	O
be	O
compatible	O
with	O
other	O
avionics	O
,	O
displays	O
,	O
etc	O
.	O
</s>
<s>
On	O
aircraft	O
avionics	O
systems	O
,	O
HUDs	B-Application
typically	O
operate	O
from	O
dual	O
independent	O
redundant	O
computer	O
systems	O
.	O
</s>
<s>
On	O
other	O
aircraft	O
(	O
the	O
Boeing	O
787	O
,	O
for	O
example	O
)	O
the	O
HUD	B-Application
guidance	O
computation	O
for	O
Low	O
Visibility	O
Take-off	O
(	O
LVTO	O
)	O
and	O
low	O
visibility	O
approach	O
comes	O
from	O
the	O
same	O
flight	O
guidance	O
computer	O
that	O
drives	O
the	O
autopilot	O
.	O
</s>
<s>
Typical	O
aircraft	O
HUDs	B-Application
display	O
airspeed	O
,	O
altitude	B-Application
,	O
a	O
horizon	O
line	O
,	O
heading	O
,	O
turn/bank	O
and	O
slip/skid	O
indicators	O
.	O
</s>
<s>
Other	O
symbols	O
and	O
data	O
are	O
also	O
available	O
in	O
some	O
HUDs	B-Application
:	O
</s>
<s>
Since	O
being	O
introduced	O
on	O
HUDs	B-Application
,	O
both	O
the	O
FPV	O
and	O
acceleration	O
symbols	O
are	O
becoming	O
standard	O
on	O
head-down	B-Application
displays	I-Application
(	O
HDD	O
)	O
.	O
</s>
<s>
target	O
designation	O
(	O
TD	O
)	O
indicator	O
—	O
places	O
a	O
cue	O
over	O
an	O
air	O
or	O
ground	O
target	O
(	O
which	O
is	O
typically	O
derived	O
from	O
radar	B-Application
or	O
inertial	O
navigation	O
system	O
data	O
)	O
.	O
</s>
<s>
During	O
the	O
1980s	O
,	O
the	O
military	O
tested	O
the	O
use	O
of	O
HUDs	B-Application
in	O
vertical	O
take	O
off	O
and	O
landing	O
(	O
VTOL	O
)	O
and	O
short	O
take	O
off	O
and	O
landing	O
(	O
STOL	O
)	O
aircraft	O
.	O
</s>
<s>
A	O
HUD	B-Application
format	O
was	O
developed	O
at	O
NASA	O
Ames	O
Research	O
Center	O
to	O
provide	O
pilots	O
of	O
V/STOL	O
aircraft	O
with	O
complete	O
flight	O
guidance	O
and	O
control	O
information	O
for	O
Category	O
III	O
C	O
terminal-area	O
flight	O
operations	O
.	O
</s>
<s>
The	O
use	O
of	O
head-up	B-Application
displays	I-Application
allows	O
commercial	O
aircraft	O
substantial	O
flexibility	O
in	O
their	O
operations	O
.	O
</s>
<s>
Unfortunately	O
these	O
tended	O
to	O
be	O
the	O
same	O
aircraft	O
that	O
as	O
standard	O
supported	O
autoland	O
(	O
with	O
the	O
exception	O
of	O
certain	O
turbo-propp	O
types	O
that	O
had	O
HUD	B-Application
as	O
an	O
option	O
)	O
making	O
the	O
head-up	B-Application
display	I-Application
unnecessary	O
for	O
Cat	O
III	O
landings	O
-	O
this	O
delayed	O
the	O
adoption	O
of	O
HUD	B-Application
in	O
commercial	O
aircraft	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
studies	O
have	O
shown	O
that	O
the	O
use	O
of	O
a	O
HUD	B-Application
during	O
landings	O
decreases	O
the	O
lateral	O
deviation	O
from	O
centerline	O
in	O
all	O
landing	O
conditions	O
,	O
although	O
the	O
touchdown	O
point	O
along	O
the	O
centerline	O
is	O
not	O
changed	O
.	O
</s>
<s>
For	O
general	O
aviation	O
,	O
MyGoFlight	O
expects	O
to	O
receive	O
a	O
STC	O
and	O
to	O
retail	O
its	O
SkyDisplay	O
HUD	B-Application
for	O
$	O
25,000	O
without	O
installation	O
for	O
a	O
single	O
piston-engine	O
as	O
the	O
Cirrus	O
SR22s	O
and	O
more	O
for	O
Cessna	O
Caravans	O
or	O
Pilatus	O
PC-12s	O
single-engine	O
turboprops	O
:	O
5	O
to	O
10%	O
of	O
a	O
traditional	O
HUD	B-Application
cost	O
albeit	O
it	O
is	O
non-conformal	O
,	O
not	O
matching	O
exactly	O
the	O
outside	O
terrain	O
.	O
</s>
<s>
Flight	O
data	O
from	O
a	O
tablet	B-Device
computer	I-Device
can	O
be	O
projected	O
on	O
the	O
$	O
1,800	O
Epic	O
Optix	O
Eagle	O
1	O
HUD	B-Application
.	O
</s>
<s>
When	O
used	O
with	O
a	O
HUD	B-Application
however	O
,	O
the	O
camera	O
must	O
be	O
mounted	O
as	O
close	O
as	O
possible	O
to	O
the	O
pilots	O
eye	O
point	O
as	O
the	O
image	O
is	O
expected	O
to	O
"	O
overlay	O
"	O
the	O
real	O
world	O
as	O
the	O
pilot	O
looks	O
through	O
the	O
combiner	O
.	O
</s>
<s>
"	O
Registration	O
,	O
"	O
or	O
the	O
accurate	O
overlay	O
of	O
the	O
EVS	O
image	O
with	O
the	O
real	O
world	O
image	O
,	O
is	O
one	O
feature	O
closely	O
examined	O
by	O
authorities	O
prior	O
to	O
approval	O
of	O
a	O
HUD	B-Application
based	O
EVS	O
.	O
</s>
<s>
This	O
is	O
because	O
of	O
the	O
importance	O
of	O
the	O
HUD	B-Application
matching	O
the	O
real	O
world	O
.	O
</s>
<s>
HUD	B-Application
systems	O
are	O
also	O
being	O
designed	O
to	O
display	O
a	O
synthetic	B-General_Concept
vision	I-General_Concept
system	I-General_Concept
(	O
SVS	O
)	O
graphic	O
image	O
,	O
which	O
uses	O
high	O
precision	O
navigation	O
,	O
attitude	O
,	O
altitude	B-Application
and	O
terrain	O
databases	O
to	O
create	O
realistic	O
and	O
intuitive	O
views	O
of	O
the	O
outside	O
world	O
.	O
</s>
<s>
In	O
the	O
1st	O
SVS	O
head	O
down	O
image	O
shown	O
on	O
the	O
right	O
,	O
immediately	O
visible	O
indicators	O
include	O
the	O
airspeed	O
tape	O
on	O
the	O
left	O
,	O
altitude	B-Application
tape	O
on	O
the	O
right	O
,	O
and	O
turn/bank/slip/skid	O
displays	O
at	O
the	O
top	O
center	O
.	O
</s>
<s>
Unlike	O
this	O
color	O
depiction	O
of	O
SVS	O
on	O
a	O
head	O
down	O
primary	O
flight	O
display	O
,	O
the	O
SVS	O
displayed	O
on	O
a	O
HUD	B-Application
is	O
monochrome	O
–	O
that	O
is	O
,	O
typically	O
,	O
in	O
shades	O
of	O
green	O
.	O
</s>
<s>
Airspeed	O
is	O
140	O
knots	O
,	O
altitude	B-Application
is	O
9,450	O
feet	O
,	O
heading	O
is	O
343	O
degrees	O
(	O
the	O
number	O
below	O
the	O
turn/bank	O
indicator	O
)	O
.	O
</s>
<s>
Under	O
such	O
conditions	O
the	O
pilot	O
is	O
given	O
a	O
graphical	O
depiction	O
of	O
where	O
the	O
aircraft	O
should	O
be	O
and	O
where	O
it	O
should	O
be	O
going	O
rather	O
than	O
the	O
pilot	O
having	O
to	O
mentally	O
integrate	O
altitude	B-Application
,	O
airspeed	O
,	O
heading	O
,	O
energy	O
and	O
longitude	O
and	O
latitude	O
to	O
correctly	O
fly	O
the	O
aircraft	O
.	O
</s>
<s>
In	O
mid-2017	O
,	O
the	O
Israel	O
Defense	O
Forces	O
will	O
begin	O
trials	O
of	O
Elbit	O
's	O
Iron	O
Vision	O
,	O
the	O
world	O
's	O
first	O
helmet-mounted	O
head-up	B-Application
display	I-Application
for	O
tanks	O
.	O
</s>
<s>
Israel	O
's	O
Elbit	O
,	O
which	O
developed	O
the	O
helmet-mounted	B-Application
display	I-Application
system	O
for	O
the	O
F-35	O
,	O
plans	O
Iron	O
Vision	O
to	O
use	O
a	O
number	O
of	O
externally	O
mounted	O
cameras	O
to	O
project	O
the	O
360°	O
view	O
of	O
a	O
tank	O
's	O
surroundings	O
onto	O
the	O
helmet-mounted	O
visors	O
of	O
its	O
crew	O
members	O
.	O
</s>
<s>
These	O
displays	O
are	O
becoming	O
increasingly	O
available	O
in	O
production	O
cars	O
,	O
and	O
usually	O
offer	O
speedometer	O
,	O
tachometer	B-Device
,	O
and	O
navigation	O
system	O
displays	O
.	O
</s>
<s>
Night	O
vision	O
information	O
is	O
also	O
displayed	O
via	O
HUD	B-Application
on	O
certain	O
automobiles	O
.	O
</s>
<s>
In	O
contrast	O
to	O
most	O
HUDs	B-Application
found	O
in	O
aircraft	O
,	O
automotive	O
head-up	B-Application
displays	I-Application
are	O
not	O
parallax-free	O
.	O
</s>
<s>
Add-on	O
HUD	B-Application
systems	O
also	O
exist	O
,	O
projecting	O
the	O
display	O
onto	O
a	O
glass	O
combiner	O
mounted	O
above	O
or	O
below	O
the	O
windshield	O
,	O
or	O
using	O
the	O
windshield	O
itself	O
as	O
the	O
combiner	O
.	O
</s>
<s>
In	O
2012	O
,	O
Pioneer	O
Corporation	O
introduced	O
a	O
HUD	B-Application
navigation	O
system	O
that	O
replaces	O
the	O
driver-side	O
sun	O
visor	O
and	O
visually	O
overlays	O
animations	O
of	O
conditions	O
ahead	O
,	O
a	O
form	O
of	O
augmented	B-General_Concept
reality	I-General_Concept
(	O
AR	B-General_Concept
)	O
.	O
</s>
<s>
Developed	O
by	O
Pioneer	O
Corporation	O
,	O
AR-HUD	O
became	O
the	O
first	O
aftermarket	O
automotive	O
Head-Up	B-Application
Display	I-Application
to	O
use	O
a	O
direct-to-eye	O
laser	O
beam	O
scanning	O
method	O
,	O
also	O
known	O
as	O
virtual	B-General_Concept
retinal	I-General_Concept
display	I-General_Concept
(	O
VRD	O
)	O
.	O
</s>
<s>
AR-HUD	O
'	O
s	O
core	O
technology	O
involves	O
a	O
miniature	O
laser	O
beam	O
scanning	O
display	O
developed	O
by	O
MicroVision	O
,	O
Inc	O
.	O
</s>
<s>
Motorcycle	O
helmet	O
HUDs	B-Application
are	O
also	O
commercially	O
available	O
.	O
</s>
<s>
Uniti	O
electric	O
city	O
car	O
will	O
replace	O
the	O
dashboard	B-Protocol
with	O
a	O
large	O
HUD	B-Application
to	O
display	O
information	O
directly	O
on	O
the	O
windscreen	O
.	O
</s>
<s>
In	O
recent	O
years	O
,	O
it	O
has	O
been	O
argued	O
that	O
conventional	O
HUDs	B-Application
will	O
be	O
replaced	O
by	O
holographic	O
AR	B-General_Concept
technologies	O
,	O
such	O
as	O
the	O
ones	O
developed	O
by	O
WayRay	B-General_Concept
that	O
use	O
holographic	B-Algorithm
optical	I-Algorithm
elements	I-Algorithm
(	O
HOE	O
)	O
.	O
</s>
<s>
Mercedes	O
Benz	O
introduced	O
an	O
Augmented	B-General_Concept
Reality	I-General_Concept
based	O
Head	B-Application
Up	I-Application
Display	I-Application
while	O
Faurecia	O
invested	O
in	O
an	O
eye	O
gaze	O
and	O
finger	O
controlled	O
head	B-Application
up	I-Application
display	I-Application
.	O
</s>
<s>
HUDs	B-Application
have	O
been	O
proposed	O
or	O
are	O
being	O
experimentally	O
developed	O
for	O
a	O
number	O
of	O
other	O
applications	O
.	O
</s>
<s>
In	O
the	O
military	O
,	O
a	O
HUD	B-Application
can	O
be	O
used	O
to	O
overlay	O
tactical	O
information	O
such	O
as	O
the	O
output	O
of	O
a	O
laser	O
rangefinder	O
or	O
squadmate	O
locations	O
to	O
infantrymen	O
.	O
</s>
<s>
A	O
prototype	O
HUD	B-Application
has	O
also	O
been	O
developed	O
that	O
displays	O
information	O
on	O
the	O
inside	O
of	O
a	O
swimmer	O
's	O
goggles	O
or	O
of	O
a	O
scuba	O
diver	O
's	O
mask	O
.	O
</s>
<s>
HUD	B-Application
systems	O
that	O
project	O
information	O
directly	O
onto	O
the	O
wearer	O
's	O
retina	O
with	O
a	O
low-powered	O
laser	O
(	O
virtual	B-General_Concept
retinal	I-General_Concept
display	I-General_Concept
)	O
are	O
also	O
in	O
experimentation	O
.	O
</s>
<s>
Head-up	B-Application
displays	I-Application
can	O
perform	O
real-time	O
language	O
translation	O
.	O
</s>
