<s>
A	O
multistatic	B-Algorithm
radar	I-Algorithm
system	O
contains	O
multiple	O
spatially	O
diverse	O
monostatic	B-Algorithm
radar	I-Algorithm
or	O
bistatic	B-Algorithm
radar	I-Algorithm
components	O
with	O
a	O
shared	O
area	O
of	O
coverage	O
.	O
</s>
<s>
An	O
important	O
distinction	O
of	O
systems	O
based	O
on	O
these	O
individual	O
radar	B-Application
geometries	O
is	O
the	O
added	O
requirement	O
for	O
some	O
level	O
of	O
data	B-General_Concept
fusion	I-General_Concept
to	O
take	O
place	O
between	O
component	O
parts	O
.	O
</s>
<s>
Multistatic	B-Algorithm
radar	I-Algorithm
is	O
often	O
referred	O
to	O
as	O
"	O
multisite	O
"	O
or	O
"	O
netted	O
"	O
radar	B-Application
and	O
is	O
comparable	O
with	O
the	O
idea	O
of	O
macrodiversity	B-Protocol
in	O
communications	O
.	O
</s>
<s>
A	O
further	O
subset	O
of	O
multistatic	B-Algorithm
radar	I-Algorithm
with	O
roots	O
in	O
communications	O
is	O
that	O
of	O
MIMO	B-Algorithm
radar	I-Algorithm
.	O
</s>
<s>
Since	O
multistatic	B-Algorithm
radar	I-Algorithm
may	O
contain	O
both	O
monostatic	O
and	O
bistatic	O
components	O
,	O
the	O
advantages	O
and	O
disadvantages	O
of	O
each	O
radar	B-Application
arrangement	O
will	O
also	O
apply	O
to	O
multistatic	O
systems	O
.	O
</s>
<s>
A	O
system	O
with	O
transmitters	O
and	O
receivers	O
will	O
contain	O
of	O
these	O
component	O
pairs	O
,	O
each	O
of	O
which	O
may	O
involve	O
a	O
differing	O
bistatic	B-Algorithm
angle	I-Algorithm
and	O
target	O
radar	B-Application
cross	O
section	O
.	O
</s>
<s>
Increased	O
coverage	O
in	O
multistatic	B-Algorithm
radar	I-Algorithm
may	O
be	O
obtained	O
via	O
the	O
spreading	O
of	O
the	O
radar	B-Application
geometry	O
throughout	O
the	O
surveillance	O
area	O
-	O
such	O
that	O
targets	O
might	O
be	O
more	O
likely	O
to	O
be	O
physically	O
closer	O
to	O
transmitter	O
receiver-pairs	O
and	O
thus	O
attain	O
a	O
higher	O
signal-to-noise	O
ratio	O
.	O
</s>
<s>
By	O
weighting	O
and	O
integrating	O
individual	O
returns	O
(	O
such	O
as	O
through	O
likelihood	O
ratio	O
based	O
detectors	O
)	O
,	O
detection	O
can	O
be	O
optimised	O
to	O
place	O
more	O
emphasis	O
on	O
stronger	O
returns	O
obtained	O
from	O
certain	O
monostatic	O
or	O
bistatic	B-Algorithm
radar	I-Algorithm
cross	O
section	O
values	O
,	O
or	O
from	O
favourable	O
propagation	O
paths	O
,	O
when	O
making	O
a	O
decision	O
as	O
to	O
whether	O
a	O
target	O
is	O
present	O
.	O
</s>
<s>
This	O
is	O
useful	O
where	O
multipath	O
or	O
shadowing	O
effects	O
might	O
otherwise	O
lead	O
to	O
the	O
potential	O
for	O
poor	O
detection	O
performance	O
if	O
only	O
a	O
single	O
radar	B-Application
is	O
used	O
.	O
</s>
<s>
Many	O
stealth	O
vehicles	O
are	O
designed	O
to	O
reflect	O
radar	B-Application
energy	O
away	O
from	O
expected	O
radar	B-Application
sources	O
in	O
order	O
to	O
present	O
as	O
small	O
a	O
return	O
to	O
a	O
monostatic	O
system	O
as	O
possible	O
.	O
</s>
<s>
Conventional	O
radar	B-Application
typically	O
has	O
a	O
much	O
poorer	O
cross-range	O
resolution	O
compared	O
to	O
down-range	O
resolution	O
,	O
thus	O
there	O
is	O
potential	O
for	O
gains	O
through	O
the	O
intersection	O
of	O
constant	O
bistatic	B-Algorithm
range	I-Algorithm
ellipses	O
.	O
</s>
<s>
use	O
of	O
Doppler	O
information	O
,	O
increase	O
in	O
down-range	O
resolution	O
or	O
addition	O
of	O
further	O
spatially	O
diverse	O
radars	B-Application
to	O
the	O
multistatic	O
system	O
)	O
.	O
</s>
<s>
Target	O
features	O
such	O
as	O
variation	O
in	O
the	O
radar	B-Application
cross	O
section	O
or	O
jet	O
engine	O
modulation	O
may	O
be	O
observed	O
by	O
transmitter-receiver	O
pairs	O
within	O
a	O
multistatic	O
system	O
.	O
</s>
<s>
Most	O
existing	O
air	O
defence	O
systems	O
utilize	O
a	O
series	O
of	O
networked	O
monostatic	B-Algorithm
radars	I-Algorithm
,	O
without	O
making	O
use	O
of	O
bistatic	O
pairs	O
within	O
the	O
system	O
.	O
</s>
<s>
Increased	O
survivability	O
and	O
"	O
graceful	O
degradation	O
"	O
may	O
result	O
from	O
the	O
spatially	O
distributed	O
nature	O
of	O
multistatic	B-Algorithm
radar	I-Algorithm
.	O
</s>
<s>
A	O
fault	O
in	O
either	O
transmitter	O
or	O
receiver	O
for	O
a	O
monostatic	O
or	O
bistatic	O
system	O
will	O
lead	O
to	O
a	O
complete	O
loss	O
of	O
radar	B-Application
functionality	O
.	O
</s>
<s>
As	O
in	O
bistatic	B-Algorithm
radar	I-Algorithm
,	O
without	O
this	O
knowledge	O
there	O
would	O
be	O
inaccuracy	O
in	O
the	O
information	O
reported	O
by	O
the	O
radar	B-Application
.	O
</s>
<s>
For	O
systems	O
exploiting	O
data	B-General_Concept
fusion	I-General_Concept
before	O
detection	O
,	O
there	O
is	O
a	O
need	O
for	O
accurate	O
time	O
and	O
or	O
phase	O
synchronisation	O
of	O
the	O
different	O
receivers	O
.	O
</s>
<s>
This	O
fusion	O
process	O
may	O
range	O
from	O
the	O
simple	O
case	O
of	O
selecting	O
plots	O
from	O
the	O
receiver	O
closest	O
to	O
a	O
target	O
(	O
ignoring	O
others	O
)	O
,	O
increasing	O
in	O
complexity	O
to	O
effectively	O
beamforming	B-Algorithm
through	O
radio	O
signal	O
fusion	O
.	O
</s>
<s>
Data	B-General_Concept
fusion	I-General_Concept
will	O
always	O
mean	O
an	O
increase	O
in	O
processing	O
compared	O
to	O
a	O
single	O
radar	B-Application
.	O
</s>
<s>
However	O
it	O
may	O
be	O
particularly	O
computationally	O
expensive	O
if	O
significant	O
processing	O
is	O
involved	O
in	O
data	B-General_Concept
fusion	I-General_Concept
,	O
such	O
as	O
attempts	O
to	O
increase	O
resolution	O
.	O
</s>
<s>
Massachusetts	O
Institute	O
of	O
Technology	O
’s	O
Netted	O
Radar	B-Application
System	I-Application
.	O
</s>
<s>
Several	O
passive	B-Algorithm
radar	I-Algorithm
systems	O
make	O
use	O
of	O
multiple	O
spatially	O
diverse	O
transmitters	O
and	O
hence	O
may	O
be	O
considered	O
to	O
operate	O
multistatically	O
.	O
</s>
