USER’S MANUAL__________________________________________________________________
220 _________________________________________________________________ M211322EN-D
N sub c = Noise level at calibration time.
N sub r = Noise level at ray processing time.
If we answer yes to "Enable noise power based correction of Z0" in the Mp
non-volatile setup section, then Figure 45 on page 216 becomes:
Figure 46 New Radar Equation
In this equation, the dBZ0 is the term . The dBZ0 fed
into the RVP900 is the basic , while the processor modifies the
value by the ratio Nr/Nc. Values read out by the GPARM command, etc.
will be the modified value.
Note that this is the only place where the calibration-time noise level Nc is
used in the processing. It is possible for this value to be unknown, in which
case it is set to "nan" internally. In this case, if you request the corrected
values, the correction will not be applied, and you will get the message
"Cannot enable Z0 noise correction because calibration is missing" in the
rvp log file.
6.3.4 Velocity
For a Doppler power spectrum that is symmetric about its mean velocity,
the velocity is obtained directly from the argument of the autocorrelation
at the first lag, that is,
λ is the radar wavelength, is the sampling time (1/PRF). θ
1
is
constrained to be on the interval [-π, π]. When θ
1
= ± π, then V =± V
u
where
the unambiguous velocity is ,
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