Download Zoom 4320A Specifications

BATS AND PORTABLE BATS
OPERATION
FILTERING provides operator a choice of various combinations of averaging, filtering, threshold
settings and also limits on certain parameters. Filtering includes averaging, target velocity checking, range gating, signal threshold, minimum xponder range, maximum xponder range and signal
rejection via signal quality checking. The filtering parameters are individual per target.
Filter Level: The Filter Level setting is variable from 1 to 10. A Filter Level setting of 1-5 is recommended for most dynamic applications (e.g., ROV tracking).
The higher settings of 6-10 are
appropriate for static applications such as station keeping. The parameter settings for the range
blanking gate and velocity filter “tighten up” as the Filter Level is increased with the premise that
dynamic targets such as AUV’s can change position quickly with respect to the vessel while static
targets such as a tow fish or other moored targets do not. Filter settings 6-10 cause the analog or
telemetry depth to average the last three readings. Filter settings 1-5 do not average the input
depth. Also see error code #5.
The table below shows the relationship between the range gate, velocity filter and averaging
weight Vs the Filter Level setting.
FILTER LEVEL/RANGE (blanking) GATE (Transponders & Responders Only)
If there is more than one sequential target the range blanking gate value is multiplied by the number of targets (e.g., filter level 2 with 4 targets enabled equates to a blanking gate of 80 meters
before the average target range). If the blanking gate exceeds the current range average then it is
set to a minimum (1m). The range average for each target is weighted based on the number of
good replies for that target. If there are no recorded good replies then the routine uses 100%
weight on the current value and is scaled down for up to 4 replies (e.g., if there have been 4 or
more consecutive good replies each new reply contributes 25% to the average). As replies are
missed, more weight gets added to the new reply. If there are more than 2 missed replies, the
blanking gate opens up by a factor of 2, until we exceed a maximum (currently 4) where it is wide
open.
TARGET FILTERING FUNCTION
Filter
Blanking Gate opens prior to av-
Velocity Filtering
Average Weighting
(4.5 m/s = 10 knots;
2.3 m/s = 5 knots)
Ratio of the weight of the
previous reply to the 10th
reply Vs Filter Level 3
erage reply (meters)
Level
1
(based on 1500m/s speed of sound)
-25 meters (-16 ms) x # Active targets
1
OFF
4.0:1
2
-20 meters x # Active targets
1
OFF
3.3:1
3
-15 meters x # Active targets 1
OFF
2.8:1
4
-10 meters x # Active targets
5
-5 meters x # Active targets
1
1
3-27
4.5 m/s + X % SR
2
2.5:1
4.5 m/s + X % SR
2
2.3:1