ROVworld Subsea Information

CodaOctopus launches pre-calibrated weather-proof mounting for Octopus F180 iner
Date: Thursday, July 03, 2008 @ 10:00:00 EDT

CodaOctopus launches pre-calibrated weather-proof mounting for Octopus F180 inertial sensorsCodaOctopus is pleased to announce an innovative new option which will significantly reduce the time taken to install a motion sensor on survey vessels of all sizes. CodaOctopus has designed a pre-calibrated weather-proof mounting to house the Octopus F180 inertial sensors and it also accommodates the twin Novatel antennas, enabling the system to be calibrated prior to being installed.

Currently available as an integrated element of the Coda Underwater Inspection System (UIS), the new mounting will be available as an optional accessory for all F180 one-box models later this year.

Conventional installation of any inertial attitude and positioning system on a vessel involves measuring offsetsbetween the primary antenna and the inertial sensors and also measuring between the antennas. The measurementsare entered into the system and accuracy is refined as the vessel then performs manoeuvres, such as figures-of-eight and circles, at varying speeds. Depending on the size of the vessel, its ability to manoeuvre and other limitations such as cost and weather, calibration can take several hours in some cases.

New precalibrated Octopus F180 mountingWith the new Octopus pre-calibrated mounting option, the offset measurements are already set and the need for calibration is removed, so speeding up installation. Once the mounting (containing the inertial sensors) is bolted into place on the vessel, the Octopus F180 system can be up and running in 15 minutes. The time-saving benefits of this new option have already been acknowledged by the US Coast Guard, currently utilising Octopus F190s on pre-calibrated mountings as part of their Coda Underwater Inspection Systems for port and harbour security.

The installation advantage was also evident in the case of BP's Schiehallion FPSO, when calibration of their Octopus F180+ simply would not have been possible using the conventional process. With the FPSO connected to sea-bed well heads, manoeuvring in figures of eight is obviously impossible and so the custom made mounting for the system eliminated this stage altogether. Within 15 minutes the critical position of the turret was being accurately measured by the F180+.

In other F180series news, three output strings have been implemented and are now available with all new Octopus F180series systems. Members of CodaOctopus team receive these additional strings for their existing F180 systems as part of their annual membership.

• Tighter integration between the Octopus F180series and the Reson range of multibeam sensors can now be achieved with the Reson UTC string.

• The implementation of the new Trimble PTNL GGK string enables the provision of time, position and height above ellipsoid. The precision of the 'height above ellipsoid' field is such that, if used with an RTK (1cm) correction, then real time tidal corrections can be performed.

• The new NMEA Rate of Turn string provides the rate of turn in units of degrees per minute. The output is passed through a new 2.5 Hz (Bessel) filter, which has been designed to produce an order of magnitude improvement in signal to noise whilst minimising phase delay.

This article comes from ROVworld Subsea Information

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