24.11.2025
Strategic partnership between CNN MCO, Thales and CS Group to modernise three amphibious helicopter carriers of the French Navy, under the project management of the Fleet Support Service
As part of the French Navy’s programme for the maintenance in operational condition (MCO) of its vessels, CNN MCO, an Equans France company, has announced a strategic partnership with Thales and CS GROUP, a subsidiary to Sopra Steria, to equip the amphibious helicopter carriers (AHC) with a new, highly resilient inertial navigation system designed for electronic warfare environments. Together, the three companies form a 100% French and sovereign industrial consortium dedicated to naval performance.
Following successful tests confirming the effectiveness of the selected solution, deployment has just been successfully completed aboard the Mistral, during its technical maintenance period at the Toulon naval base.
The French Navy’s Fleet Support Service (SSF) is leading this initiative to upgrade navigation systems on the PHA-type amphibious helicopter carriers and has tasked CNN MCO as its fleet support contract holder with completing the work. Awarded in 2022 for a period of eight years, CNN MCO's contract covers all onboard systems on the three PHA vessels: Mistral, Tonnerre and Dixmude.
It also includes in-service support of the Somme BCR-type command and underway replenishment vessel. The objective is to ensure the availability at sea and full operational capability of these platforms in an increasingly demanding strategic environment. To address the progressive obsolescence of certain critical systems, the contract includes more than 40 modernisation studies. Conducted across three separate vessels, these studies have already resulted in 50 upgrades in the last two years. CNN MCO is managing these phases in close coordination with the SSF, from preliminary design studies through to shipboard integration
Autonomous, reliable navigation in the face of new threats
In a context of hybrid conflicts and widespread jamming of radionavigation systems, the French Navy is strengthening the autonomy and resilience of its navigation systems. The TopAxyz inertial navigation system developed by Thales relies solely on internally controlled data with no dependence on external sources.
Using shipboard sensors such as accelerometers and gyroscopes, TopAxyz measures the vessel’s movements to continuously calculate its position, speed and heading, without the need for external signals such as GPS. The result of over 40 years of expertise and experience, these systems have logged more than 50 million hours of operations across a wide range of applications, from space to civil and military aviation and land platforms.
With this technology, enhanced by spoofing and jamming detection functionality, the Navy is strengthening its ability to navigate reliably with a high degree of precision and discretion, even in the most sensitive areas.
A tailor-made navigation system
Within the consortium, CS GROUP, a subsidiary of Sopra Steria, brings its leading expertise in navigation systems. The Thales inertial navigation units will be integrated into CS Group’s global navigation system. As the navigation system forms the backbone of a warship — ensuring positioning accuracy and manoeuvring safety — this technological partnership guarantees precision, resilience and service continuity in the most demanding maritime environments.
With over 15 years of experience, CS GROUP has mastered the integration of all navigation sensors, the development of resilient and cyber-secure navigation data distribution systems, and the serial production of rugged embedded systems for harsh environments. The integration of these new systems, carried out by CNN MCO, complies with stringent safety requirements and leverages existing infrastructures.
To date, the retrofit studies have required nearly 1,500 hours of engineering by CNN MCO’s in-house design office, in partnership with Thales and CS Group.
Phased rollout coordinated with scheduled maintenance
Installation of these navigation systems and related equipment is aligned with the SSF’s vessel maintenance schedule through to 2027. The Mistral will be the first to benefit from the new system, followed by the Dixmude and Tonnerre. Once the Thales inertial units have been integrated into the navigation modules by CS Group, the systems will be installed by CNN MCO across the three vessels, with a progressive ramp-up aligned with this timeline. CNN MCO is responsible for integration, test supervision and equipment maintenance, working directly with the SSF teams. The aim is to optimise installation windows in order to ensure the operational availability of the systems at sea.
“This programme confirms CNN MCO’s ability to carry out complex upgrades in shipboard environments. We’re proud to contribute to the modernisation of sensitive equipment on these vessels as part of an all-French initiative, working with the SSF, Thales and CS Group.” – Céline Barazer, Deputy Director of CNN MCO, an Equans France company
“With 40 years of experience in inertial navigation systems for aircraft, space launchers, air defence systems and artillery, Thales is now bringing this know-how to naval operations. We’re proud to play a part in providing resilient navigation solutions for France's naval vessels as a prerequisite for ensuring freedom of action by armed forces at sea.” – Florent Chauvancy, Vice-President, Flight Avionics, Thales
“By contributing alongside CNN MCO and Thales to a 100% French solution, we reaffirm the importance of sovereign expertise serving the French Navy. A long-standing partner of the naval forces, CS GROUP is proud to support the fleet’s performance and safety, and to ensure the coherent and resilient integration of the entire navigation chain.” — Frédéric Dussart, Director, Defence & Security Activities, CS Group
