<s>
Cosine	B-Error_Name
error	I-Error_Name
occurs	O
in	O
measuring	O
instrument	O
readings	O
when	O
the	O
user	O
of	O
an	O
instrument	O
does	O
not	O
realize	O
that	O
the	O
vector	O
that	O
an	O
instrument	O
is	O
measuring	O
does	O
not	O
coincide	O
with	O
the	O
vector	O
that	O
the	O
user	O
wishes	O
to	O
measure	O
.	O
</s>
<s>
Rather	O
than	O
measuring	O
the	O
desired	O
vector	O
(	O
in	O
this	O
case	O
,	O
orthogonal	B-Application
width	O
)	O
,	O
the	O
instrument	O
is	O
measuring	O
the	O
hypotenuse	O
of	O
a	O
triangle	O
in	O
which	O
the	O
desired	O
vector	O
is	O
in	O
fact	O
one	O
of	O
the	O
legs	O
.	O
</s>
<s>
The	O
cosine	O
of	O
this	O
triangle	O
correlates	O
to	O
how	O
much	O
error	O
exists	O
in	O
the	O
measurement	O
(	O
hence	O
the	O
name	O
cosine	B-Error_Name
error	I-Error_Name
)	O
.	O
</s>
<s>
Although	O
many	O
workers	O
might	O
not	O
use	O
the	O
term	O
"	O
cosine	B-Error_Name
error	I-Error_Name
"	O
to	O
name	O
this	O
mistake	O
(	O
instead	O
calling	O
it	O
"	O
failing	O
to	O
measure	O
squarely	O
"	O
)	O
,	O
the	O
underlying	O
concept	O
is	O
the	O
same	O
.	O
</s>
<s>
A	O
context	O
in	O
which	O
potential	O
cosine	B-Error_Name
error	I-Error_Name
must	O
often	O
be	O
considered	O
is	O
in	O
the	O
use	O
of	O
an	O
indicator	O
(	O
distance	O
amplifying	O
instrument	O
)	O
.	O
</s>
<s>
Cosine	B-Error_Name
error	I-Error_Name
can	O
also	O
affect	O
laser	O
interferometry	O
.	O
</s>
<s>
Another	O
context	O
in	O
which	O
potential	O
cosine	B-Error_Name
error	I-Error_Name
draws	O
attention	O
is	O
in	O
lidar	O
traffic	O
enforcement	O
and	O
radar	O
traffic	O
enforcement	O
,	O
where	O
drivers	O
assert	O
that	O
the	O
speed	O
measurement	O
was	O
in	O
error	O
because	O
the	O
lidar	O
or	O
radar	O
signal	O
was	O
emitted	O
in	O
a	O
direction	O
not	O
directly	O
along	O
the	O
line	O
of	O
travel	O
.	O
</s>
<s>
(	O
Cosine	B-Error_Name
error	I-Error_Name
always	O
reduces	O
the	O
measured	O
speed	O
,	O
thus	O
favoring	O
the	O
motorist	O
.	O
)	O
</s>
<s>
It	O
is	O
demonstrably	O
true	O
that	O
missile-guiding	O
radars	O
are	O
capable	O
of	O
accurately	O
measuring	O
the	O
oblique	O
movements	O
of	O
enemy	O
aircraft	O
under	O
a	O
variety	O
of	O
conditions	O
,	O
but	O
to	O
what	O
degree	O
traffic	O
enforcement	O
radar	O
or	O
lidar	O
succeeds	O
at	O
this	O
problem	O
has	O
been	O
challenged	O
by	O
defendants	O
,	O
who	O
speak	O
of	O
the	O
cosine	O
effect	O
or	O
cosine	B-Error_Name
error	I-Error_Name
effect	I-Error_Name
.	O
</s>
<s>
The	O
longer	O
the	O
length	O
of	O
the	O
instrument	O
,	O
the	O
easier	O
it	O
is	O
to	O
control	O
cosine	B-Error_Name
error	I-Error_Name
.	O
</s>
<s>
If	O
the	O
instrument	O
is	O
very	O
small	O
,	O
then	O
optical	O
alignment	O
techniques	O
can	O
be	O
used	O
to	O
reduce	O
cosine	B-Error_Name
error	I-Error_Name
.	O
</s>
