Graphics Programs Reference
In-Depth Information
where , , , , ,
, , and (from Chapter 3 ). The search
pulsewidth is and the track waveforms are .
First consider the missile case. The single pulse SNR at the maximum detec-
tion range
G
=
34.5 dB
λ
=
0.1 m
T e
=
290 Kelvin
F
=
6 dB
L
=
8 dB
0.5 m 2
4 m 2
σ m
=
σ a
=
P t
=
20 KW
τ′
=
20µ s
12.5µ s
i
20µ s
m
R max
=
55 Km
is given by
) 2
10 3
–
6
10 3.45
) 2
20
×
×
20
×
10
×
(
×
(
0.1
×
0.5
SNR m
=
--------------------------------------------------------------------------------------------------------------------------------------
=
(5.47)
) 4
4( 3
10 3
–
23
10 0.8
10 0.6
×
(
55
×
×
1.38
×
10
×
290
×
×
8.7028
SNR m
=
9.39 dB
Alternatively, the single pulse SNR, with pulse compression, for the aircraft is
) 2
10 3
–
6
10 3.45
) 2
20
×
×
20
×
10
×
(
×
(
0.1
×
4
SNR a
=
--------------------------------------------------------------------------------------------------------------------------------------
=
(5.48)
) 4
4( 3
10 3
–
23
10 0.8
10 0.6
×
(
90
×
×
1.38
×
10
×
290
×
×
9.7104
SNR m
=
9.87 dB
Using these calculated SNR values into the MATLAB program
Ðmyradar_visit2_2.mÑ (see Chapter 2) yields
P DC Aircarft
=
0.999
(5.49)
P DC Missile
=
0.9984
which clearly satisfies the design requirement of
P D
0.995
.
Next, consider the matched filter and its replicas and pulsed compressed out-
puts (due to different waveforms). For this purpose use the program
Ðmatched_filter_gui.mÑ. Assume a receive window of 200 meters during
search and 50 meters during track.
Fig. 5.15 shows the replica and the associated uncompressed and com-
pressed signals. The targets consist of two aircraft separated by 50 meters. Fig.
5.16 is similar to Fig. 5.15, except it is for track waveform number 4 and the
target separation is 20 m.
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