Graphics Programs Reference
In-Depth Information
P c
2πσ t
f 2
t 2
W ()
=
-------------------
exp
(
–
)
(7.33)
where is the clutter power (constant), and is the clutter rms frequency
(which describes the clutter spectrum spread in the frequency domain). It is
given by
P c
σ t
σ 2
σ 2
σ 2
σ t
=
++
(7.34)
is the standard deviation for the clutter spectrum spread due to wind veloc-
ity; is the standard deviation for the clutter spectrum spread due to antenna
scanning; and is the standard deviation for the clutter spectrum spread due
to the radar platform motion (if applicable). It can be shown that 1
σ v
σ s
σ v
w
λ
σ v
=
----------
(7.35)
Θ a T scan
σ s
=
0.265
-------------------
(7.36)
v
---
σ s
sin
θ
(7.37)
where
λ
is the wavelength and
σ w
is the wind rms velocity;
Θ a
is the antenna
3-db azimuth beamwidth (in radians);
T scan
is the antenna scan time;
v
is the
platform velocity; and
θ
is the azimuth angle (in radians) relative to the direc-
tion of motion.
The clutter power at the input of an MTI filter is
f 2
t 2
P c
2πσ t
C i
=
-------------------
exp
–
---------
d
(7.38)
–
Factoring out the constant
P c
yields
f 2
t 2
1
2πσ t
C i
=
P c
---------- - -----
exp
–
---------
d
(7.39)
–
It follows that
1. Berkowtiz, R. S., Modern Radar, Analysis, Evaluation, and System Deign , John
Wiley & Sons, New York, 1965.
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