Correct installation parameters are crucial for sonar operation

The quality and accuracy of the ST90 presentations depend on the hull unit being correctly installed, and that all necessary parameters related to this installation have been entered into the software

Ship origin / Ship dimensions

When you have several different sensors and transducers on your vessel, and you wish each of them to provide accurate data, you need to know their relative physical positions. To do this, you must establish one or more common reference points. This reference point is also used to position the sonar echoes relative to the ship symbol on the display presentation.

Use the Ship page to define a specific reference point (Ship Origin or origo) for the various sensors connected to the ST90 system. Do this as accurately as possible. This information is used to create a new origin in the vessel coordinate system.

Transducer

When the installation trunk is mounted, it may not be positioned with the mounting holes perfectly aligned to the centre line of the vessel. When the hull unit is placed on the trunk, the "forward" mark on the transducer shaft sleeve - and thus also "forward" on the transducer - may not point forward at all, but several degrees off the centre line. To obtain accurate echo presentations, this misalignment must be adjusted by changing the installation parameters.

Note:

Providing the correct value for this rotation is crucial for the sonar performance. An inaccurate or incorrect value will cause the sonar echoes to be presented at the wrong bearing.

Use the Transducer page to define the physical location of the transducer in the vessel coordinate system, as well as the installation angles (rotation). Do this as accurately as possible.

Motion sensor

The physical rotation of the motion reference unit (MRU) relative to the transducer is required to allow the ST90 system to adjust for roll and pitch as accurately as possible.

Note:

Correct values for motion sensor rotation are critical for the sonar performance.

Use the MRU (Motion Reference Unit) page to insert the physical location and rotation of the motion reference sensor (MRU) with reference to the vessel coordinate system.

The Installation Parameters pages allow you to define the relationship between the physical locations of the various sensors and the transducer. All relevant system units and sensors must be defined with their physical offset values in relation to the defined Ship Origin in the vessel’s coordinate system. You will only need to define these installation parameters once. These pages are located in the Installation dialog box.