Kongsberg Simrad ST90, Reference Manual

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System description
The Simrad ST90 is a long range and low frequency fish finding sonar with a 360 degrees
coverage. The ST90 system is designed for medium and large sized fishing vessels.
If high performance is your number 1 criteria when choosing a sonar; such as long range,
high resolution, narrow beams and high source levels, this is your natural choice. We made
no compromises during the design of the ST90 system. Our goal was simply to make
the ultimate high performance fish finding sonar. With the ST90 system we use lower
frequencies than the SX90 and SU90 sonars. In order to achieve this, a completely new
transducer has been designed. Each element is larger than the previous SX90 and SU90
elements, but the number of elements is the same as the SU90. This allows for the same
narrow beam, and ultimately a longer range. The ST90 system has been designed to search
with very long ranges in all weather and sea conditions. Whether it is heavy weather, hard
bottom, open waters, weak targets - all echoes are handled by the ST90 system due to the
fully stabilized and very narrow beams combined with the cutting edge signal processing.
The centre operational frequency is XXXXX kHz. You can select any operational frequency
from 14 to 24 kHz.
The cylindrical multi-element transducer allows the omnidirectional sonar beams to be
tilted electronically. This allows you to automatically track schools of fish, and to observe
the whole water volume around the vessel.
The ST90 system offers a number of standard interface lines for communication with
peripheral devices and sensors. Typical inputs are geographical information from a
positioning system, vessel speed and current heading. By default, the ST90 system uses a
built-in motion sensor. For improved operational accuracy, an external motion reference unit
(MRU) can be connected.
The narrow beam opening angle and the high source level makes the ST90 system a very
powerful and high resolution low frequency sonar. The narrow beams provided by the
ST90 system give you several advantages.
• They increase the range and resolution, and offer a vertical view with additional details
and a clearer picture.
• They make the ST90 system even more ideal when you need to search for fish close to
the sea bottom, or close to the surface, at long ranges.
• They provide a far better vertical view with less "bottom climbing" that what is seen on
sonars with a wider beam.
• The narrow beams also decrease the noise level.
The ST90 system offers the same user interface and operating software as our other sonars,
echo sounders and catch monitoring systems. This enables easier and faster training of
new users.
Simrad ST90 Reference Manual