<s>
Pulse-Doppler	B-Algorithm
signal	I-Algorithm
processing	I-Algorithm
is	O
a	O
radar	B-Application
and	O
CEUS	O
performance	O
enhancement	O
strategy	O
that	O
allows	O
small	O
high-speed	O
objects	O
to	O
be	O
detected	O
in	O
close	O
proximity	O
to	O
large	O
slow	O
moving	O
objects	O
.	O
</s>
<s>
This	O
signal	O
processing	O
strategy	O
is	O
used	O
in	O
pulse-Doppler	B-Algorithm
radar	I-Algorithm
and	O
multi-mode	O
radar	B-Application
,	O
which	O
can	O
then	O
be	O
pointed	O
into	O
regions	O
containing	O
a	O
large	O
number	O
of	O
slow-moving	O
reflectors	O
without	O
overwhelming	O
computer	O
software	O
and	O
operators	O
.	O
</s>
<s>
It	O
is	O
also	O
used	O
to	O
measure	O
blood	O
flow	O
in	O
Doppler	B-Algorithm
ultrasonography	I-Algorithm
.	O
</s>
<s>
Pulse-Doppler	B-Algorithm
begins	O
with	O
coherent	O
pulses	O
transmitted	O
through	O
an	O
antenna	O
or	O
transducer	O
.	O
</s>
<s>
This	O
disruption	O
causes	O
some	O
of	O
the	O
transmit	O
energy	O
to	O
be	O
reflected	O
back	O
to	O
the	O
radar	B-Application
antenna	O
or	O
transducer	O
,	O
along	O
with	O
phase	B-Device
modulation	I-Device
caused	O
by	O
motion	O
.	O
</s>
<s>
The	O
same	O
tone	O
that	O
is	O
used	O
to	O
generate	O
the	O
transmit	O
pulses	O
is	O
also	O
used	O
to	O
down-convert	B-Algorithm
the	O
received	O
signals	O
to	O
baseband	B-Algorithm
.	O
</s>
<s>
The	O
reflected	O
energy	O
that	O
has	O
been	O
down-converted	O
to	O
baseband	B-Algorithm
is	O
sampled	O
.	O
</s>
<s>
Samples	O
are	O
collected	O
until	O
the	O
radar	B-Application
begins	O
to	O
fire	O
another	O
transmit	O
pulse	O
.	O
</s>
<s>
Enough	O
samples	O
must	O
be	O
taken	O
to	O
act	O
as	O
the	O
input	O
to	O
the	O
pulse-Doppler	B-Algorithm
filter	O
.	O
</s>
<s>
Phase	O
coherence	O
of	O
the	O
transmit	O
signal	O
is	O
crucial	O
for	O
pulse-Doppler	B-Algorithm
operation	O
.	O
</s>
<s>
Pulse-Doppler	B-Algorithm
signal	I-Algorithm
processing	I-Algorithm
separates	O
reflected	O
signals	O
into	O
a	O
number	O
of	O
frequency	O
filters	O
.	O
</s>
<s>
These	O
samples	O
are	O
organized	O
into	O
the	O
m×n	O
matrix	B-Architecture
of	O
time	O
domain	O
samples	O
shown	O
in	O
the	O
top	O
half	O
of	O
the	O
diagram	O
.	O
</s>
<s>
Detection	O
processing	O
for	O
pulse-Doppler	B-Algorithm
produces	O
an	O
ambiguous	O
range	O
and	O
ambiguous	O
velocity	O
corresponding	O
to	O
one	O
of	O
the	O
FFT	O
outputs	O
from	O
one	O
of	O
the	O
range	O
samples	O
.	O
</s>
<s>
For	O
monopulse	B-Algorithm
radar	I-Algorithm
,	O
signal	O
processing	O
is	O
identical	O
for	O
the	O
main	O
lobe	O
and	O
sidelobe	O
blanking	O
channels	O
.	O
</s>
<s>
The	O
sorted	O
detections	O
are	O
processed	O
with	O
a	O
range	B-Algorithm
ambiguity	I-Algorithm
resolution	I-Algorithm
algorithm	O
to	O
identify	O
the	O
true	O
range	O
and	O
velocity	O
of	O
the	O
target	O
reflection	O
.	O
</s>
<s>
Pulse	B-Algorithm
Doppler	I-Algorithm
radar	I-Algorithm
may	O
have	O
50	O
or	O
more	O
pulses	O
between	O
the	O
radar	B-Application
and	O
the	O
reflector	O
.	O
</s>
<s>
Pulse	B-Algorithm
Doppler	I-Algorithm
relies	O
on	O
medium	O
pulse	O
repetition	O
frequency	O
(	O
PRF	O
)	O
from	O
about	O
3kHz	O
to	O
30kHz	O
.	O
</s>
<s>
The	O
received	O
signals	O
from	O
multiple	O
PRF	O
are	O
compared	O
using	O
the	O
range	B-Algorithm
ambiguity	I-Algorithm
resolution	I-Algorithm
process	O
.	O
</s>
<s>
The	O
received	O
signals	O
are	O
also	O
compared	O
using	O
the	O
frequency	B-Algorithm
ambiguity	I-Algorithm
resolution	I-Algorithm
process	O
.	O
</s>
<s>
Invalid	O
signals	O
include	O
microwaves	O
made	O
by	O
sources	O
separate	O
from	O
the	O
transmitter	O
,	O
such	O
as	O
radar	B-Application
jamming	O
and	O
deception	O
.	O
</s>
<s>
The	O
radar	B-Application
uses	O
a	O
polar	O
coordinate	O
system	O
.	O
</s>
<s>
The	O
antenna	O
must	O
be	O
aimed	O
at	O
the	O
position	O
which	O
will	O
paint	O
the	O
target	O
with	O
maximum	O
energy	O
and	O
not	O
dragged	O
behind	O
it	O
,	O
otherwise	O
the	O
radar	B-Application
will	O
be	O
less	O
effective	O
.	O
</s>
<s>
The	O
amplitude	O
and	O
phase	O
for	O
the	O
signal	O
returned	O
by	O
the	O
reflector	O
is	O
processed	O
using	O
monopulse	B-Algorithm
radar	I-Algorithm
techniques	O
during	O
track	O
.	O
</s>
<s>
This	O
is	O
called	O
angle	B-Algorithm
error	I-Algorithm
.	O
</s>
<s>
The	O
radius	O
of	O
the	O
capture	O
volume	O
is	O
approximately	O
the	O
distance	O
the	O
fastest	O
detectable	O
vehicle	O
can	O
travel	O
between	O
successive	O
scans	O
of	O
that	O
volume	O
,	O
which	O
is	O
determined	O
by	O
the	O
receiver	O
band	O
pass	O
filter	O
in	O
pulse-Doppler	B-Algorithm
radar	I-Algorithm
.	O
</s>
<s>
Pulse-Doppler	B-Algorithm
track	O
information	O
includes	O
object	O
area	O
,	O
errors	O
,	O
acceleration	O
,	O
and	O
lock	O
state	O
,	O
which	O
are	O
part	O
of	O
the	O
decision	O
logic	O
involving	O
join	O
tracks	O
and	O
split	O
tracks	O
.	O
</s>
