10.4.3 User Manual Contents April 17, 2020
Firmware: 5.2.1 Page 50 of 142
Sets the rate at which acoustic pulses are transmitted. Certain factors such as depth will limit
the maximum achievable ping rate. For instance, in deeper water, lower ping rates will be the
norm since signal travel time and path length from projector to reflective bottom, and then
back to receiver, are longer. Tx pulse Mode also affects ping rate. The system automatically
transmits with 200µs sweep time in shallow waters so that maximum ping rate is maintained.
If enabled, sets the ping rate to maximum possible value over the total effective range as
defined by the Swath width, swath Direction and Lower Gate. Ping rate is a function of the
two-way travel-time of the signal from projector to the bottom and back, plus a small duration
for ping processing and capacitor charge. The effective range is determined from the angular
swath width, swath pointing angle and lower depth or range gate.
System searches for greatest bottom detection range based on adaptive gate over a certain
number of pings and revises the transmission timing to match this. Lower Gate may therefore
be set to very deep values, but the system will ping at a much higher rate as it is based on
maximal adaptive gate for range. This is ideal for high resolution data over rapidly changing
bottoms or for surveys that don’t allow for full-time, hands-on operators (e.g. on AUVs). While
operating in this mode, sonar bandwidth and sweep time are determined by the Lower Gate.
If surveying in shallow waters, the Lower Gate should not be set too deep unless Auto
Mode/Resolution is disabled.
Sets the maximum ping rate of the sonar. Even if possible, the sonar will not ping faster than
the fixed rate. Useful for general bathymetric surveys with deep and shallow water to reduce
data volume in very shallow waters as the system will continually attempt to ping as fast as
possible up to the user defined threshold or the sonar range.
Most users do not require this. Ping is triggered externally and only happens if the sonar is
‘ready’ when the signal arrives, e.g. if the sonar cannot ping faster than 10Hz due to range,
but the external signal is 12Hz, then every other event will be skipped resulting in a 6Hz ping
rate per every other signal. The external signal polarity is configurable. Minimum delay from
transmit signal to center of transmit pulse is 500µs (half the transmit pulse buffer plus
additional). An adjustable trigger delay is possible in millisecond resolution.
If checked, this option directs sonar to sweep an along-track sector of angle given by Opening
Angle. If unchecked, the sonar is directed to ping in one direction, effectively behaving as a
conventional multibeam sonar. NOTE: It is not advised to conduct an entire multibeam
survey with scanning active. Use scanning only when attempting to further develop
areas of interest. For most applications, step size should be limited to 20.
This is configurable only if Scanning is enabled and the opening angle is set to a non-zero
value. The number of steps corresponds to the number of slices, or pings, in each defined
along-track sector.
The value in this field defines the angular direction forming the center of the along-track
sector, e.g. for a direction of 5°, and opening angle 20°, the STX will scan across a sector
from -5° to 15°.
Display all
Ang (STX
only):
If checked, this instructs the GUI to display all angles in the sector being scanned by the STX.
If unchecked, the GUI will display the angle defined in Display Angle.
Display
Angle
(STX only):
If Display all Ang is unchecked, this field will be greyed out. However, if the previous field is
unchecked, the user may define a single angle within the sector to visualize on the display.
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