Simrad ST90

Long-range 14-24 kHz fish-finding omnidirectional sonar

The Simrad ST90 is a long-range and low-frequency fish-finding sonar with 360 degrees coverage. It is specifically designed for medium and large-sized fishing vessels, offering high performance with characteristics such as long-range capability, high resolution, narrow beams, and high source levels. The ST90 represents a no-compromise approach in sonar technology, aiming to be the ultimate in high-performance fish-finding. Utilizing lower frequencies than the SX90 and SU90 sonars, the ST90 embodies innovative developments made by Simrad in pursuit of unparalleled sonar performance.

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. With the Simrad ST90, we use lower frequencies than the SX90 and SU90 sonars.

The centre operational frequency is 19 kHz, but you can select any operating 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 will enable you to automatically track schools of fish and observe the whole water volume around the vessel.

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-degree 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.

WINSON operating software

The SIMRAD ST90 uses the latest "Winson" software. This unique software platform is common for all Simrad sonars. It allows you to present the various sonar echoes in separate views, which can be placed on separate display monitors. Another great feature of the new software is its ability to "ping" all the beams simultaneously. This increases the ping rate and thus offers a more frequent update of the sonar echoes in the views.

Sonar operating panel

You can set up your SIMRAD ST90 sonar with the Mk2 Sonar Operating Panel. This operating panel uses a handy multifunction joystick. The joystick facilitates tilt, vertical, and inspection beam control through simple pushes or twists of the knob. The operating panel communicates with the Processor Unit using an Ethernet connection. This communication format allows for advanced functionality. You can manage up to four different SIMRAD sonars using a single panel. Conversely, up to three panels in various locations on the vessel can operate a single sonar. The USB port on the operating panel also provides convenient software upgrades and user settings management. The sonar operating panel also features dedicated and customizable buttons and knobs, and its design allows for a straightforward upgrade from older panels using a mounting bracket.

Advanced transducer design

Our goal was to make the ultimate high-performance fish-finding sonar. To achieve this task, we designed a completely new transducer. 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, or 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.

Superior sonar capabilities

The narrow beam opening angle of the ST90 (6.5° @ 17 kHz) in conjunction with the high source level makes it a formidable tool for high resolution, low-frequency sonar exploration. The advantages of these narrow beams include enhanced range and resolution and a vertical view that yields additional details for a clearer image. This sonar is especially advantageous when pinpointing fish near the seafloor or surface at extended distances. Furthermore, the beams reduce noise levels and mitigate bottom climbing, a common issue in wider beam sonars. Another noteworthy feature is the ability to construct all sonar views from a single ping, significantly improving the update rate and providing real-time information.

Intuitive operation and connectivity

Providing several standard interface lines ensures seamless communication with peripheral devices and sensors, with typical inputs like geographical information, vessel speed, and heading. The built-in motion sensor, with options for an external MRU, enhances operational accuracy. The Simrad ST90 also emphasizes user-friendly interfaces and top-tier sonar presentations on high-resolution color monitors. It features advanced signal processing software inclusive of Hyperbolic FM (HFM) transmissions, or 'chirp' for a clutter-free picture and superb range resolution. The tracking function has been refined to utilize horizontal and vertical transmission echoes, underscoring the intuitive nature and advanced capabilities of the sonar system.


Keep your SIMRAD ST90 updated with the latest software version. Follow us on social media to keep up with the changes, and contact your dealer for upgrades. For the latest software version, check the dedicated MF90 software article.

End-user documentation

All relevant user- and installation manuals, certificates and drawings for the SIMRAD ST90 fish-finding sonar are available. To access the information, open the relevant article using the link at the bottom of this page. Several formats are provided, including interactive electronic technical manuals (IETM). Selected publications are also available in additional languages.

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