These flag bits are output in the optional flag word. The second pass called Clutter sensoring
involves linearly interpolating all the autocorrelation values in range over the interval of
clutter bins including the osets at either sides if the oset is larger than 1:
0
=
*
0
+
*
0
, ℎ =
,
Note that the same thing is done for all the filtered autocorrelations and crosscorrelations
(lagged moments R
1
, R
2
, and dual-polarization crosscorrelations) as soon as any of the
filtered autocorrelation R
0H
, R
0V
, or R
0HV
exceeds the threshold. The unfiltered
autocorrelations (total power) T
0H
, T
0V
, and T
0HV
are conserved.
7.4.2
Range Averaging and Clutter Microsuppression
Range averaging can be performed over 2, 3, ..., 16 bins. This reduces the number of bins in
the
final output to save processing both in the RVP900 and in the host computer.
This is accomplished by averaging the T
0
, R
0
, R
1
and R
2
values.
At the user's option, the range averaged data can be restricted to include only those bins
which have an estimated clutter-to-signal ratio that falls within the CCOR threshold interval.
By excluding isolated point clutter targets from the range average the sub-clutter visibility
of the averaged data is increased. Specifically, the Doppler test that is applied to each bin in
order that it contribute to the overall sum is:
10log
0
10log
0
>
ℎℎ
The total power T
0
is conserved after the exclusion of the isolated point clutter targets.
More Information
‣
Range Averaging and Clutter Microsuppression (page 44)
7.4.3
Reflectivity
The corrected reflectivity Z is output using a log scale based on the following equation:
= 10log
0
+
0
+ 20log + +
This equation is a dB version of the familiar radar equation for distributed targets. The
relationship between the measured autocorrelation function, the received signal and the
noise can be expressed as:
0
=
+
where g
t
and g
r
represent the transmitter and receiver gains, S is the average back
scattered power from the targets and N is the measured average noise power. Neglecting
attenuation and the contribution of ground clutter (for the moment), the radar equation can
be written as.
RVP900 User Guide M211322EN-J
200
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