Impact Subsea has developed the ISM3D underwater attitude and heading reference system (AHRS).
The ISM3D utilizes high grade MEMS (micro-electro mechanical systems) based accelerometers, angular rate gyroscopes and magnetometers all of which feed into an advanced fusion engine driven by a dual core micro-processor.
The unit provides heading to ±0.5° of local magnetic north with pitch and roll to ±0.05° accuracy.
For optimal performance, a hard and soft iron calibration can be performed on the unit once installed on the remotely operated vehicle, autonomous underwater vehicle or other underwater platform, to a provide consistent and accurate heading.
In areas where a large amount of steel of other magnetic disturber is present, the unit can be switched to operate using the angular rate gyroscopes and accelerometers, without input from the magnetometer. The low drift rate of the advanced MEMS based gyroscopes enables navigation to be conducted in areas where previously only a fiber or ring laser diode based heading sensor would suffice. In addition, the unit is provided in a titanium housing that is 65mm-long and depth rated to 6000m.
'With the ISM3D we have built on the AHRS capability packaged within our other products," said Ben Grant, managing director, Impact Subsea. "Utilizing extremely high grade MEMS sensors has enabled the creation of a high accuracy underwater sensor in a very compact housing."
The ISM3D will be on display at Ocean Business, Southampton, 4-6 April 2017, Stand A29.
Image: ISM3D/Impact Subsea