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Simrad ST90

The Simrad ST90 is a long-range and low-frequency fish-finding sonar with 360 degrees coverage. The ST90 is designed for medium and large-sized fishing vessels.

If high performance is your number 1 criterion when choosing a sonar, such as long range, high resolution, narrow beams and high source levels, the Simrad ST90 is your natural choice. We made no compromises during the design of the ST90. Our goal was to make the ultimate high-performance fish-finding sonar. With the Simrad ST90, we use lower frequencies than the SX90 and SU90 sonars.


To achieve this, a completely new transducer was designed. Each transducer element is larger than the SX90 and SU90 elements, but the number of elements is the same as the SU90. This high number of elements allows for the same narrow beam and a longer range. The ST90 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 sonar due to the fully stabilized and very narrow beams combined with the cutting edge signal processing.

The centre operational frequency is 19 kHz, but you can select any operational frequency from 14 to 24 kHz in steps of 1 kHz. The cylindrical multi-element transducer allows the omnidirectional sonar beams to be tilted electronically from -10 to +84 degrees. These features allow you to track schools of fish automatically and to observe the whole water volume around the vessel.

The narrow beam opening angle (6.5° @ 17 kHz) and the high source level makes the ST90 a very powerful and high resolution low frequency sonar. The narrow beams provided by the ST90 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 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" than what is seen on sonars with a wider beam.
  • The narrow beams also decrease the noise level.

It is common for sonars to require many pings to build the various views in the echo presentation. These sonars may, for example, need one ping to build the 360 degrees omni view and then several other pings to fetch the echoes for the vertical views. On the ST90, all the sonar views in the presentation are built using the echoes from one single ping. This feature dramatically improves the update rate and provides better real-time information.

Providing several standard interface lines makes communicating with peripheral devices and sensors easy. Typical inputs are geographical information from a positioning system, vessel speed and the vessel's current heading. By default, the sonar uses a built-in motion sensor. An external motion reference unit (MRU) can be connected for improved operational accuracy.

The echo presentations are optimized for multiple displays. Provided that you have connected additional displays to your Processor Unit, you can use the Docking Views function to take any sonar view and place it on a separate display monitor. When you move an echo view to another display monitor, it will automatically be scaled for the best possible result.

It is common for sonars to require many "pings" to build the various views in the echo presentations. We create the echo presentations using the echoes from one single ping. This functionality dramatically improves the update rate and provides better real-time information.

You can record real-time sonar situations. This recording function allows you to replay complete echo sequences. The playback contains the same echo information. You can use it for mission history, training or troubleshooting purposes.

Compared to our previous sonars, we have improved the tracking function. It can now use echo information from both the horizontal and vertical transmissions.

We have placed great emphasis on an intuitive user interface and the best possible sonar presentations on a high-resolution colour monitor.

The sonar offers our celebrated signal processing software. This software includes Hyperbolic FM (HFM) transmissions. This pulse type is also known as "chirp". It ensures a clutter-free picture with a very high range resolution. The signal processing and beamforming are performed in a fast digital signal processing system using the full dynamic range of the echo signals.

Services and support

  • 24/7 Technical support

    Our 24/7 technical support team is there to help at any time, day or night, wherever your vessel is.

  • Conversions, retrofit and refit

    We understand the importance of having the right parts, available in the right place, at the right time.

  • Training

    Ensure that your crew is properly and thoroughly trained. This will reduce operational risk, downtime and maximise return on asset investment.