<s>
The	O
UDOP	B-Algorithm
(	O
UHF	O
Doppler	O
)	O
multistatic	O
radar	O
and	O
multiradar	O
system	O
(	O
MSRS	O
)	O
utilizes	O
Doppler	B-Algorithm
radar	I-Algorithm
for	O
missile	O
tracking	O
and	O
trajectory	O
measurement	O
.	O
</s>
<s>
Five	O
receiving	O
stations	O
,	O
located	O
along	O
the	O
baselines	O
with	O
the	O
lengths	O
from	O
,	O
receive	O
signals	O
from	O
the	O
target	O
's	O
transponder	B-Architecture
at	O
900MHz	O
.	O
</s>
<s>
UDOP	B-Algorithm
had	O
relatively	O
low	O
cost	O
compared	O
with	O
other	O
high-accuracy	O
systems	O
.	O
</s>
<s>
These	O
MSRSs	O
include	O
the	O
AZUSA	B-Application
,	O
the	O
MISTRAM	O
,	O
and	O
the	O
UDOP	B-Algorithm
.	O
</s>
<s>
All	O
systems	O
employ	O
a	O
cooperative	O
beacon	O
transponder	B-Architecture
on	O
the	O
observed	O
target	O
and	O
a	O
ground-based	O
transmitting	O
station	O
with	O
several	O
receiving	O
stations	O
at	O
separate	O
,	O
precisely	O
located	O
sites	O
.	O
</s>
<s>
The	O
UDOP	B-Algorithm
used	O
an	O
AN/DRN	O
-11	O
transponder	B-Architecture
installed	O
in	O
the	O
Saturn	O
(	O
rocket	O
family	O
)	O
launch	O
vehicle	O
for	O
Project	O
Gemini	O
missions	O
.	O
</s>
<s>
The	O
C-band	B-Algorithm
CW	O
interferometric	O
AZUSA	B-Application
,	O
in	O
operation	O
from	O
the	O
1950s	O
,	O
has	O
one	O
transmitter	O
and	O
nine	O
receivers	O
located	O
along	O
two	O
crossed	O
baselines	O
with	O
the	O
total	O
lengths	O
of	O
about	O
.	O
</s>
<s>
The	O
AZUSA	B-Application
system	O
measures	O
range	O
by	O
phase	O
measurement	O
of	O
sideband	O
frequencies	O
modulating	O
the	O
carrier	O
,	O
coherent	O
range	O
by	O
Doppler	O
count	O
,	O
two	O
direction	O
cosines	O
,	O
and	O
two	O
cosine	O
rates	O
.	O
</s>
<s>
The	O
system	O
was	O
augmented	O
in	O
1965	O
by	O
short	O
baselines	O
of	O
a	O
few	O
meters	O
to	O
a	O
few	O
hundred	O
meters	O
in	O
contrast	O
to	O
the	O
conventional	O
UDOP	B-Algorithm
system	O
with	O
baselines	O
of	O
several	O
kilometers	O
and	O
longer	O
.	O
</s>
<s>
The	O
UDOP	B-Algorithm
system	O
was	O
used	O
extensively	O
for	O
the	O
Saturn	O
program	O
at	O
the	O
NASA	O
John	O
F	O
.	O
Kennedy	O
Space	O
Center	O
(	O
NASA-KSC	O
)	O
.	O
</s>
<s>
UDOP	B-Algorithm
is	O
a	O
2-way	O
,	O
coherent	O
,	O
continuous-wave	O
,	O
tracking	O
system	O
.	O
</s>
<s>
The	O
UDOP	B-Algorithm
system	O
,	O
a	O
descendant	O
of	O
Doppler	O
Velocity	O
and	O
Position	O
(	O
DOVAP	O
)	O
was	O
developed	O
by	O
NASA-KSC	O
.	O
</s>
<s>
UDOP	B-Algorithm
consists	O
of	O
three	O
basic	O
elements	O
:	O
</s>
<s>
A	O
simplified	O
,	O
functional	O
block	O
diagram	O
of	O
the	O
close-in	O
UDOP	B-Algorithm
tracking	O
system	O
is	O
shown	O
in	O
the	O
figure	O
.	O
</s>
<s>
The	O
50MHz	O
is	O
multiplied	O
to	O
450MHz	O
and	O
transmitted	O
to	O
the	O
transponder	B-Architecture
on	O
board	O
the	O
vehicle	O
as	O
an	O
interrogation	O
signal	O
.	O
</s>
<s>
The	O
transponder	B-Architecture
receives	O
the	O
450MHz	O
signal	O
,	O
doubles	O
and	O
re-transmits	O
at	O
900MHz	O
.	O
</s>
<s>
The	O
ground	O
stations	O
simultaneously	O
receive	O
the	O
50MHz	O
reference	O
signal	O
and	O
the	O
900MHz	O
transponder	B-Architecture
signal	O
.	O
</s>
<s>
The	O
UDOP	B-Algorithm
ground	O
receivers	O
are	O
double	O
,	O
superheterodyne	O
,	O
dual-channel	O
units	O
with	O
common	O
local	O
oscillators	O
.	O
</s>
<s>
The	O
UDOP	B-Algorithm
digitized	O
data	O
recorded	O
from	O
each	O
receiver	O
station	O
was	O
fed	O
to	O
a	O
computer	O
which	O
calculated	O
positions	O
X	O
,	O
Y	O
,	O
and	O
Z	O
.	O
</s>
<s>
The	O
origin	O
for	O
the	O
UDOP	B-Algorithm
system	O
is	O
at	O
the	O
vehicle	O
transmitting	O
antenna	O
at	O
vehicle	O
launch	O
position	O
.	O
</s>
