USER’S MANUAL__________________________________________________________________
46 __________________________________________________________________ M211322EN-D
bin. This type of averaging is useful to lower the number of range bins that
the host computer must process.
Range averaging of the autocorrelations may be performed over 2 bins to
16 bins. Prior to range averaging, any bins that exceed the selectable
clutter-to-signal threshold are discarded. This prevents isolated strong
clutter targets from corrupting the range average, which improves the
sub-clutter visibility.
2.9.1.5 Moment Extraction
The autocorrelations serve as the basis for the Doppler moment
calculations:
- Mean velocity—From Arg [ R1 ]
- Spectrum width—From |R1| and |R2| assuming Gaussian spectrum
- dBZ—From R0 with correction for ground clutter, system noise, and
gaseous attenuation. Uses calibration information supplied by host
computer
- dBT—Identical to dBZ, except without ground clutter
These are the standard parameters that are output to the host application.
2.9.1.6 Thresholding
The RVP900 calculates several parameters that are used to threshold
(discard) bins with weak or corrupted signals. The thresholding parameters
are:
- Signal quality index (SQI=|R1|/R0)
- LOG (or incoherent) signal-to-noise ratio (LOG)
- SIG (coherent) signal-to-noise ratio
- CCOR clutter correction
These parameters are computed for each range bin and can be applied in
AND/OR logical expressions, independently for dBZ, V, and W.
2.9.1.7 Speckle Filter
The speckle filter can be selected to remove isolated single bins of either
velocity/width or intensity. This feature eliminates single pixel speckles,
which allows the thresholds to be reduced for greater sensitivity with fewer
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