
ZENO
®
-3200 USER MANUAL
Coastal Environmental Systems (206) 682-6048 Page D-15
When the vehicle is stationary, the True Wind Vector Average Process can
only provide true wind speed and true wind direction data if a compass is
installed.
The vehicle's course over ground and speed over ground can be obtained from a GPS receiver.
332
If no
compass is present, the orientation of the anemometer must be provided as a constant input for Line Item
#6, the Compass Input. The orientation is specified so that the measured wind direction will be zero
degrees when the anemometer is pointing toward the front (or bow) of the vehicle.
The process uses the following calculations to determine true wind speed (S
true
), true component wind
direction (DC
true
) and true independent wind direction (DI
true
) from the measured wind speed (S
meas
),
measured wind direction (D
meas
), compass (C), speed over ground (S
gnd
) and course over ground (D
gnd
):
2.5. Barometric Pressure Process
Inputs: 4 Barometric pressure sensor or process input
Outputs: 1 Average sea level Barometric pressure
2 Most recent sea level Barometric pressure calculation
E1 Process Error Code
Assumptions: Data input to this function should be scaled to millibars
This process calculates immediate barometric pressure (P
imm
) and average barometric pressure that are
corrected to sea level by using the Barometer Elevation (H
baro
) parameter located in the System Functions
Menu.
333
The measured barometric pressure (P
meas
) is corrected by a factor of one millibar for every 8
meters that the barometric pressure sensor is above sea level using the following equation:
The average barometric pressure is calculated across the Sample Interval from the corrected immediate
barometric pressure using equations similar to the Averaging Process.
334
332
Refer to Section 10.3.4.
333
Refer to Section 5.8.
334
Refer to Category #1, Process #2.
true
true
true
truetruetruetruetruetrue
true
true
true
truetruetrue
vehicleitruevehicleitrue
gndgndvehiclegndgndvehicle
truemeasitruemeasi
x
y
DI
SvySux
u
v
DC
vuS
vvvuuu
DSvDSu
CDSvCDSu
arctan
,
arctan
,
cos,sin
cos,sin
22
8
baro
measimm
H
PP
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