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where
Symbol
Description
Units
Status
np
number of integrated pulses
none
input
pfa
probability of false alarm
none
input
pd
probability of detection
none
input
impr_of_np
improvement factor
output
dB
The integration loss is defined as
L
NCI
=
n
P
⁄
In
()
(2.50)
Figure 2.6b
shows a plot of the integration loss versus . This figure can be
reproduced using MATLAB program
Ðfig2_6b.mÑ
given in Listing 2.8 in Sec-
tion 2.11. It follows that, when non-coherent integration is utilized, the corre-
sponding SNR required to achieve a certain
n
P
P
D
given a specific
P
fa
is now
given by
(
SNR
)
NCI
=
(
n
P
×
(
SNR
)
)
⁄
L
NCI
(2.51)
1
which is very similar to Eq. (1.86) derived in
Chapter 1.
2.4.3. Mini Design Case Study 2.1
An L-band radar has the following specifications: operating frequency
, operating bandwidth
f
0
=
1.5
GHz
B
=
2
MHz
, noise figure
F
=
8
dB
,
system losses
L
=
4
dB
, time of false alarm
T
fa
=
12
minutes
, detection
range
R
=
12
Km
, the minimum required SNR is
SNR
=
13.85
dB
, antenna
1
m
2
gain , and target RCS . (a) Determine the PRF , the
pulsewidth , the peak power , the probability of false alarm , the corre-
sponding , and the minimum detectable signal level . (b) How can you
reduce the transmitter power to achieve the same performance when 10 pulses
are integrated non-coherently? (c) If the radar operates at a shorter range in
the single pulse mode, find the new probability of detection when the range
decreases to
G
=
5000
σ
=
f
r
τ
P
t
P
fa
P
D
S
min
9
Km
.
A Solution
Assume that the maximum detection corresponds to the unambiguous range.
From that the PRF is computed as
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