During the Sea Air Space 2017 show in Washington, DC, Naval Sea Systems Command (NAVSEA) highlighted the coming advent of digital solid-state technologies over legacy MILSPEC analog ones. NAVSEA commented on the benefits sought in such a shift: advanced performances, ease of maintenance, enhanced availability and lowest total cost of ownership.

Naval navigation is currently witnessing a transformation, notably in the field of inertial technology. Recent months have seen some of the most demanding navies in the world discarding legacy inertial technologies in favor of a full, strap-down, solid-state technology: Fiber Optic Gyroscopes (FOG). The most striking example of such a mutation is certainly the Royal Navy decision in 2016 to retrofit their 35 major combatant surface ships and submarines with FOG inertial systems, following its previous selection of FOG for the new Queen Elisabeth-Class aircraft carriers and Astute-class nuclear submarines.

iXblue, a global leader in the design and manufacture of innovative solutions for navigation and positioning purposes, is recognized as the driving force behind this transformation. MARINS series, iXblue’s range of MILSPEC FOG inertial systems, has established itself as the new standard for combat vessels as witnessed by its recent selection by numerous navies (UK, Germany, UAE, Sweden, France...). On top of it, MARINS M7, Royal Navy’s choice, offers an unrivalled drift performance of less than 1nm in 72 hours in pure inertial mode for application in surface GNSS-denied or stealth submarine navigations. 

Guillaume Dandrieux, former naval officer and iXblue’s director of business development for naval affairs, explains: “The medium-term preeminence of FOG technology in the strategic naval field was anticipated some years ago by several recognized experts in the inertial domain, such as those found at the Massachusetts Institute of Technology (MIT) and the Draper Laboratory in Cambridge, MA. They acknowledged that FOG technology was to become unchallenged for strategic applications. The advent of FOG systems is therefore not a surprise and the US Navy is turning towards this technology for all of their future needs. iXblue has been the accelerator of this transition in the naval domain. It is the result of our deliberate R&D program over the last 30 years. We develop, manufacture and integrate internally all components to include optical fiber, coil winding, modulator and laser sources to maintain full control over the global system performance chain. This policy allows us to continue to reach for the highest performance while the possibilities offered by FOG technology are theoretically unlimited.”

Fiber Optic Gyroscope technology (FOG) relies on the same physical principles as the elder Ring Laser Gyroscope (RLG), but with true solid-state strap-down architecture. This differentiation relieves FOG from all well-known drawbacks experienced by RLG users. Unlike RLG, FOG components’ properties do not wear out with time and usage. This positively impacts the system’s lifetime and exempts the users from unnecessary preventive maintenance and intermediary recalibration work. Solid-state architecture makes the system intrinsically silent with no radiated interference noise. In a FOG, two identical laser beams are injected and propagate in opposite directions through a fibre optic coil. The actual angular velocity of the coil, hence of the system, is then accurately measured by an interferometric measurement of the resulting phase difference between both beams. iXblue makes its FOG impervious to temperature changes and magnetic disturbance through advanced modelling of environmental sensitivities, specific designs and in-house testing and calibration. They are made resistant to extreme shocks and vibrations to meet the most stringent military requirements.

Another big advantage of FOG is its low electrical consumption compared to other technologies. FOG inertial systems offer a very good compromise in terms of low electrical performance and radiated heat versus size and drift performance. This is a prerequisite to equip underwater systems like UAV, SDV and ROV where these constraints, along with the necessary noise discretion, are paramount. Guillaume Dandrieux comments: “iXblue equips a majority of UAV systems for defense purposes. Our range of PHINS C-series is specifically designed for OEM integration within UAV systems of all sizes. We have developed strong collaborations with UAV suppliers to make these PHINS C-series INS perfectly fitted for their systems and applications. In addition, we propose acoustic positioning solutions that together with the FOG INS authorize hybrid navigation with even greater performance”. In March 2017, two iXblue MARINS M7 have been ordered by SPAWAR Pacific to equip the LDUUV prototype under development by the US Office of National Research. The language used to support this purchase communicated the position iXblue currently holds in this market: “The iXblue MARINS M7 INS possesses unique and highly specialized capabilities for undersea autonomous navigation. The MARINS M7 is a proprietary integrated navigation system which, to the government’s knowledge, provides the best available position, velocity and heading accuracy in a package which can be mounted within a UUV. No alternative systems exist which can allow for the critical unaided (pure inertial) navigation required to support the UMTJC2 mission”.

Today, iXblue equips more than 35 navies worldwide. This enviable position has just been reached over the last 15 years. “We entered this market initially through retrofits while expanding our range of solutions. Now, iXblue FOG INS and AHRS are selected more often by our customers for their new ship designs. The iXblue family of AHRS/INS covers all types of requirements, from IMO-compliant AHRS designed for patrol ships under civilian classification rules up to full MILSPEC-compliant INS for submarines and aircraft carriers. Navies relying on iXblue systems benefit from the advantages of an up-to-date, solid-state technology with high reliability and availability and the best performance offered in the industry. In addition, iXblue systems share strong commonalities with regards to hardware, software, and interfaces. This results in significant savings at the fleet level in terms of integration, installation, configuration management, logistics, training and maintenance costs.

NETANS: Smart Data Distribution Units in an era of Navigation Warfare

Inertial is not the only domain in which iXblue is paving the way of a technological transition. Recent years have seen the development of NETANS, a new range of smart naval Data Distribution Units (DDU), tailored to meet the most challenging requirements of surface and subsurface combatant ships. Guillaume Dandrieux explains: “With the numerous retrofits we carried out on board all types of naval platforms, we rapidly realized that the best exploitation of the performance we offered with our inertial systems was not being achieved. We often had to interface with DDUs that were limited in terms of functionalities and capabilities. DDUs used merely to redistribute data from the various navigation sensors without bringing any additional value or intelligence in the navigation system chain. The decision was then made by iXblue to develop a range of scalable smart DDUs able to bring added value and meet the new challenges met by modern navies.“

Indeed, with the advent of military-grade GNSS systems, single-source uninterrupted, accurate and reliable real-time navigation data was once made easily accessible to surface vessels. At the same time, subsurface platforms remained very dependent on diverse sources of sensor data which has to be assessed, compared and post-processed to build up coherent and reliable navigation information. However, recent intense development in threats to GNSS signals has raised strong concerns in the military. To compound matters, navigation information has become even more critical for the success of naval operations, particularly as a significant contributor to the effective performance of increasingly sophisticated sensors and effectors on board surface combatants and submarines.

These developments put even more critical demands on navigation information, in terms of performance, reliability, robustness and availability. Moreover, there is a discernible trend towards convergence in surface and subsurface requirements, notably with regard to resilience in hostile environments.

To this end, iXblue NETANS DDUs do not only distribute the individual sensor data, they also acquire, analyze, correlate, validate, select and, if needed, raise alarms or even reject the diverse input data, to elaborate the most complete real-time merged and consolidated Navigation Information available to subscriber systems (and most notably the Combat System). Built-in navigation algorithms deliver the most reliable, coherent and accurate information, relying on the most consistent data (inertial, GNSS, magnetic, terrain, log, etc.), whatever the environmental conditions. NETANS key features include built-in redundancy management, hot-swapping capability and sensor auto-recognition to ensure data robustness, integrity and validity. NETANS DDUs are simple to install, with an integration process reduced to simple pre-recorded settings, easy to use through an intuitive interface, versatile and scalable. “NETANS has been installed on numerous combatant ships in the last decade to the satisfaction of all their naval users. iXblue MARINS / NETANS suite offers an unprecedented level of capability as a backbone for integrated navigation systems”

With the NETANS series, iXblue once again extends its scope of expertise in the Navigation domain, to bring the best-in-class navigation solutions and to achieve superiority in naval operations