The purpose of this publication is to provide the descriptions, procedures and detailed parameter explanations required to allow for safe and efficient use of the ST90 system. The publication also provides you with a thorough understanding of the parameters and adjustments provided by the ST90 system.
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
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.
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. 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.
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. This task is only applicable is you are using an external motion reference unit on your ST90 system. Correct values for motion sensor rotation are critical for the sonar performance.
The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the ST90 system to increase the accuracy of the echo data. The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. It is placed inside the Motor Control Unit.
The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. It is placed inside the Motor Control Unit. For improved operational accuracy, an external motion reference unit (MRU) can be used. It is very important that the motion sensor is set correctly with stabilization offset values that are adapted to the physical installation angles of the hull unit. To align an external motion sensor to the internal sensor, you may need to adjust the stabilization offset values. This task is only applicable is you are using an external motion reference unit on your ST90 system.
The technical specifications summarize the main functional and operational characteristics of the ST90 system. They also provide information related to power requirements, physical properties and environmental conditions.
The ST90 system can send and receive information to and from several different peripherals. All transmissions take place as datagrams with data sentences. Each datagram has a defined format and length.
