Artemis BP00707, Руководство пользователя

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Target Visibility
Targets that lie within the 90° sector (and the range of the sonar) will be shown on the
display, while targets that lie outside this area can’t be shown.
In the vertical plane, the sonar beam is 35° wide (regardless of scan angle), and again
targets within this beam will be visible, while targets above or below won’t be seen…
For each mechanical scan position, the sonar display shows the received echo strength
(as colour brightness) against distance from the sonar. This means the display could be
thought of as being very similar to an overhead “satellite” image, but with a few key
differences, discussed below…
Target (& Echo) Intensity
As the acoustic beam scans across the 90° field of vision, the sound travels from the
sonar (at approximately 1500 metres per second in water) until it hits the first target in
its path.
Depending on its composition, the target then reflects some proportion of this acoustic
energy back towards the sonar, which is received and displayed (with a colour
corresponding to the sound level received).
The greater the density difference of the target is to water, the more acoustic energy is
reflected.
 Gas bubbles, photo-synthesising aquatic plants, rocks, or any gas filled thin walled
targets will appear very brightly along with very solid metal or concrete structures.
 Thin walled, water-filled or water-logged targets (i.e. barrels, canisters, wooden
crates etc) will reflect some, but not as much sound as a solid target.
 Mud, silt or other particles in suspension are good absorbers and will return very
little acoustic energy.