iXBlue expands growing range of positioning products

In April, iXBlue unveiled what it describes as its “next generation” of underwater acoustic positioning systems, GAPS-NG. Like its predecessor GAPS, GAPS-NG is a portable, pre-calibrated ultra-short baseline (USBL) positioning system that incorporates an inertial navigation system (INS) and global positioning system (GPS) technology. GAPS was designed to work in demanding environments, notably acoustically challenging and/or extremely shallow water, where other systems commonly fall down.

“Our overall aim with the new system was to make life easier and better for the user,” said Hubert Pelletier, sales and marketing director at the company’s acoustic products division. “We know that users value the basic performance advantages that GAPS offers, but we wanted to make the system more flexible and easier to use, and also to improve its functionality.

“We have listened to our customers and come up with a package of measures to respond to the feedback we have received from customers over the past few years.”

iXBlue has improved GAPS principally by providing the system with new, generic I/Os, ethernet connectivity and its standard web-based man-machine interface (MMI) – an interface already available across the product range that enables the system to be interrogated via the web and its operating parameters very simply modified on screen.

The enhancements make GAPS-NG compatible with more underwater transponders and easier to interface with a variety of peripheral systems and sensors. The result, says the company, is a more practical underwater positioning system that can be quickly adapted to a variety of applications. GAPS is widely used for towfish and diver tracking, and remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) navigation and positioning. The company claims that GAPS-NG opens up the possibility of applications involving telemetry and dynamic positioning.

“We feel that with GAPS-NG we have taken underwater positioning to the next level,” claimed Mr Pelletier. “We expect a series of applications to emerge as users begin to appreciate the practical benefits of the new system.”

Recent weeks have also seen iXBlue enhance the functionality of inertial navigation system PHINS, which provides position, heading, attitude, depth and heave data. Its high accuracy inertial measurement capability is based on iXBlue’s fibre-optic gyroscope technology.

The new DP-PHINS product is designed to interface with any third-party acoustic positioning equipment to provide INS-enhanced acoustic data input to a dynamic positioning (DP) system. DP-PHINS can also take data from a range of additional sensors, some not normally associated with DP, such as Doppler velocity logs, for use in maintaining vessel position.

The company notes that using INS with acoustics in this way produces positioning data that is more accurate and is updated at a higher rate. As a result, stationkeeping performance is significantly improved, vessels use less fuel, and wear and tear on the DP system components is reduced.

A spokesperson for iXBlue said DP-PHINS was developed at the request of one of the world’s leading subsea engineering and construction companies, which operates a large fleet of specialist vessels. The company was keen to improve the quality of the acoustic data provided to the DP systems on its vessel systems. This was because, during GPS ‘outages’, purely acoustic data was not able to control the DP systems with the level of reliability that the company required. This was particularly the case when operating in deep water, when acoustic data can often be degraded by excessive noise.

Jim Titcomb, offshore technical manager at iXBlue, said the DP-PHINS system had been thoroughly tested in collaboration with the client. “We found that acoustic positioning data delivered to the vessel’s DP desk was up to three times more accurate than the data produced when using acoustic equipment on its own. We are now planning to deploy the system on a commercial basis with the client for routine operations,” he explained.

April also saw Forum Subsea Rentals, the Aberdeen-based equipment rental specialist make a further significant investment in inertial navigation technology from iXBlue. The latest investment makes Forum Subsea Rentals one of the world’s largest stockists of iXBlue products.

The equipment is due to be utilised for ROV positioning in survey and construction support applications on major projects worldwide. The contract includes a quantity of Rovins subsea inertial navigation systems as well as Octans gyrocompasses. The Octans gyrocompasses can be upgraded to the full INS capability of the Rovins.

The positioning solution provided by Rovins can be enhanced with the use of a Doppler velocity log which can be coupled directly to the INS or fitted elsewhere on the vehicle. In either case, for best performance, it is necessary to perform an alignment calibration procedure. Although this can be performed on site, users often prefer to have the sensors coupled and calibrated prior to mobilisation to a project.

iXBlue engineers assisted Forum in the preparation and calibration of six Rovins/DVL sets to be mobilised to a project early in 2013. A survey vessel was hired for a week during which the coupled systems were calibrated and a number of Forum engineers were fully trained in the procedure by the iXBlue engineers. OSJ