Oculus M-Series Sonar
User Manual
16
3.3.
Target Visibility
Objects (or targets) that lie within the sonar’s beam will be acoustically “illuminated” and can have their echoes
received (target
), while objects that lie outside this (targets
and
) may not appear on the sonar display:
It should be noted that although the above diagrams show a boundary to the sonar beam, but this actually
represents the ‘half
-
power’ level of the sound waves.
Vertical targets outside this area may still be visible on the
display, but their echo level will decrease quickly as they get further away from the beam pattern.
Horizontally, images outside the beam pattern are not shown because of the fixed width nature of th
e ‘top
-
down’
display.
The sonar cannot determine the echoes incoming vertical arrival angle, so if two targets are in front of the sonar
at the same range vertically above each other the sonar will show both these as a single result made up from a
combination of their echoes.
