The MS70 has been designed for target strength measurements of objects in the water column. In order to obtain precision data that are both detailed and correct, it is necessary to align the transducer, measure the location and offset of each sensor in relation to the vessel’s coordinate system, and calibrate the complete
MS70 prior to use. Modest accuracy requirements apply when your MS70 system is only used to investigate objects in the water column.
The quality assurance tasks required for MS70 include:
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Aligning the transducer during installation |
The alignment and dimensional surveying must be done during the MS70 installation with the vessel in dry dock. The first calibration is normally done at sea during the Sea Acceptance Test. This calibration may not be complete, and must then be repeated later. The calibration is then repeated at regular interfaces, and prior to each survey.
Alignment
The alignment tasks required for MS70 include:
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Measure and adjust the transducer to ensure that it has been mounted horizontally within the given tolerances. |
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Measure and adjust the transducer to ensure correct orientation. |
NoteAligning the transducer for correct installation within the given tolerances requires professional skills. The installation engineers from Kongsberg Maritime are neither equipped nor trained to align a transducer, and they have no means of verifying the results until calibration at sea has been done.
Dimensional surveying
The dimensional surveying tasks required for MS70 include:
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Defining the vessel coordinate system The vessel coordinate system is established to define the relative physical locations of systems and sensors. 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.
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Defining the location of the origin in the coordinate system The origin is the common reference point where all three axis in the vessel coordinate system meet. All physical locations of the vessel’s sensors (radar and positioning system antennas, echo sounder and sonar transducers,
motion reference units etc) are referenced to the origin.
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Defining the vessel’s centre line |
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Measuring the location and orientation of each sensor (or sensor antenna) in the coordinate system By means of the vessel coordinate system, the physical location of every sensor can be defined using three numerical values
for X, Y and Z. These values must define the vertical and horizontal distances from a single reference point; the origin. The accuracy of the three numerical values for X, Y and Z defines the accuracy of the sensor data.
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Measuring the location and orientation of the MS70 transducer in the coordinate system |
NoteDetermining the relative positions and orientations of the sensors and the transducer with high accuracy is important. This requires professional land surveying done by qualified and trained surveyors using proven survey equipment and methods
. We recommend that you use third party consultants with well proven experience with vessel dimensional control. Sufficient time and satisfactory work conditions must be given to the survey work. The installation engineers from Kongsberg Maritime are neither equipped nor trained to do dimensional surveying.
The information provided by the dimensional survey is entered into the MS70 software as installation parameters.
Calibration
During the sea trials, calibration surveys are required as described in the MS70 end user documentation.
In order to check and verify the performance of the MS70 system, we strongly recommend that calibration surveys are done at regular intervals, or prior to any large survey. If existing sensors have been replaced, or new sensors have been installed, a new calibration is always required. A new calibration may also be required after an update of the MS70 software. Refer to the software release note.
The information provided by the calibration is entered into the MS70 software as operational parameters. This is done automatically.
NoteCalibration must be taken seriously. The final verification of correct installation can only be done during calibration at sea. Installation and operational parameters that do not meet the accuracy requirements may lead to a malfunctioning MS70 system. To achieve the best results, the calibration must be planned and done carefully. If the accuracy requirements are not met, and this is found to be the reason for a malfunctioning system, the vessel will
most likely need to be dry docked in order to repeat the dimensional survey.