The hemispheric resonator gyroscope (HRG) revisited: An interview with Safran

The high-end inertial system market is expected to feel significant effects from covid-19, especially in applications associated with commercial aerospace, such as aircraft navigation and attitude heading. Yole Développement (Yole) outlines this in its recent report High-End Inertial Sensors for Defense, Aerospace and Industrial Applications 2020. One key aspect of this market lies in the multitude of technologies used, both older and newer ones.

High-end inertial sensor technologies have historically gone through various cycles, which typically span 20 years, from the technology’s first application to its maturity. Initially, mechanical gyros appeared, and then optical ring laser gyroscopes (RLGs) and fiber optic gyroscopes (FOGs) followed. Those are very mature technologies, typically used in legacy aerospace and defense applications. Currently, MEMS technologies are focused on achieving better performance to compete with the traditional technologies. At the same time, hemispheric resonator gyroscopes (HRGs) have reached maturity and could widen the application spectrum, thanks to interesting breakthroughs in high-volume manufacturing by Safran. This may change the landscape in the mid-to-long-term, with traditional RLGs, FOGs and other mechanical gyro businesses at the receiving end of increased competition. To gain more insight on the HRG activities of Safran Electronics and Defense (SED), Yole Custom Project Business Developer, Dimitrios Damianos PhD spoke with Yan Lenoir, VP of Safran’s navigation programs.

High-end inertial technology maturity

Dimitrios Damianos (DD): Safran is well-known in the high-end inertial system market. Having a diversified portfolio of all kinds of gyro and inertial measurement unit (IMU) technologies for numerous applications, what would you say are your company’s strengths and your products’ killer applications and volume drivers?

Yan Lenoir (YL): Our leading position in the high-end inertial system market is the result of our expertise across the full spectrum of inertial technologies as well as our mastering the most cutting-edge technologies. This technological expertise enables Safran to provide inertial navigation solutions for all applications. Three product killers stand out from Safran’s portfolio. Firstly, a tactical airborne combat IMU designed for Safran’s AASM HAMMER. Secondly comes the Geonyx family for land vehicles. Thirdly come the ADIRU and Skynaute products for commercial aircraft.

DD: How have the last one to two years been for your high-end inertial business? What were the main drivers?

YL: Over the past two years, Safran has introduced its new generation of HRG-based Inertial Navigation System (INS) designed to equip all types of platform. At Eurosatory and Euronaval in 2018, Safran launched Geonyx for land vehicles as well as Argonyx and Black-Onyx for surface vessels and submarines. With the best cost, size weight and power (C-SWaP) for inertial navigation systems in the market, Safran’s then-new HRG-based ONYX core broke down market performance standards. These performance metrics, specifically unrivalled mean time between failures (MTBF) and low cost of ownership, were welcomed by customers.

DD: Safran recently announced a breakthrough in HRG manufacturing. What were the main technical challenges that you had to overcome and how did you overcome them?

YL: Safran Electronics & Defense has constantly invested in R&D in order to develop disruptive gyroscope technologies based on the Coriolis effect, specifically HRG, CVG and MEMS.
Our success is based on the ability to overcome industrial challenges through the large-scale manufacturing of a resonating gyro fitted with flat electrodes, the HRG Crystal. For the purpose of sustaining our transition from RLG to HRG, Safran has invested in a high-tech manufacturing facility called CORIOLIS, in service since 2012. Developing this industrial facility has enabled us to acquire mass-production capabilities.
Furthermore, in parallel with the development of high-tech means of production, Safran has been able to break the market standard through innovation. Indeed, Safran’s HRG Crystal scores better than 0.0001°/h, which brings this technology one step closer to quantum gyro performance.

HRG Crystal
Courtesy of Safran

DD: Could you explain briefly where HRGs could be positioned, besides very high end markets such as space? What are the technical requirements for HRGs to successfully enter these markets?

YL: Safran is indeed well positioned in the high-end market segments such as space. For instance, Ariane 6 space launchers are equipped with HRG-based SpaceNaute INS. HRG’s range of application is however much broader. Safran’s HRG versatility enables the technology to address all civilian and defense market segments.

DD: What are HRG’s technical strengths/weaknesses against RLG, FOG and MEMS?

YL: Not only is Safran’s HRG Crystal competitive regarding costs of ownership, but it also much more versatile when it comes to its range of high-volume applications. From strategic ballistic missiles to tactical weapons in the military domain and from commercial gyrocompass to ADIRU in the civilian domain, HRG is able to address the full spectrum of volume driver market segments.

In order to so, HRG relies on different competitive advantages. Whereas a FOG’s performance is constrained by fiber length, HRGs do not depend on gyro size, but rather on the balancing quality of the resonator. A similar relation between laser length and navigation accuracy applies to RLG technology, which has much higher manufacturing costs than Safran’s HRG Crystal. Hence, HRG Crystal is more competitive than other technologies in terms of both performance/price ratio and performance scalability. In this respect, it has the best C-SWaP of any navigation grade inertial unit in the market.

Although Safran was the first manufacturer of resonating gyros at industrial scale, it was not the first manufacturer of this technology. For the past 20 years, Northrop Grumman has produced HRG designed for space applications. Due to its low-volume high-value applications, Northrop Grumman’s HRG is positioned at the very high end of the performance/price matrix and is subsequently not strongly competitive outside space applications. Safran has overcome HRG’s initial lack of competitiveness through successful industrialization.

Navigation requirements vary a great deal according to platform missions, performance, environment, market prices or even usage time, among other numerous factors. Safran’s ability to master the full spectrum of inertial navigation technologies enables the company to offer the most suitable solution to address each market need.

DD: How does Safran position against its competitors’ technologies and what are your value propositions?

YL: Safran is the number one company in Europe and number three worldwide for inertial navigation systems used in air, land and naval applications. Over the past four years, Safran has broken down past market standards by introducing a major technological breakthrough relying on a patented technology, the HRG CrystalTM, whose unique performance levels have been acknowledged in the US by DARPA. This technological lead enables Safran to provide the best C-SWaP navigation solutions portfolio designed to address all types of applications. In addition to these characteristics, HRG CrystalTM has a long MTBF that provides Safran’s navigation solutions with highly competitive costs of ownership and reduced maintenance costs.

High End Inertial Safran
Courtesy of Safran

DD: We have seen a lot of consolidation in the high-end inertial and end-user markets. What’s your view on that?

YL: The outbreak of covid-19 and the subsequent global economic crisis are likely to trigger adjustments in high-end inertial key players’ market positions. Surely, players addressing most of the main military and civilian segments of inertial navigation markets will be in a stronger position to cope with the aftermath of the current economic crisis. The current situation will also provide governments with more incentives to safeguard inertial businesses concerned with sovereign activities, especially in the military segments. Should merger and acquisition opportunities arise, we expect the consolidation trend to continue in the years to come.

DD: China is believed to be ramping up its domestic inertial volume production, especially on the MEMS side, to increase industrial and other autonomous-everything applications. Do you have a better view on the Chinese market? What is Safran doing to better penetrate this market?

YL: The high number of academic and scientific articles on HRG and MEMS published in China highlights Chinese enduring interest in resonating technologies. This being said however, typical lead-time to reach high technology readiness levels and manufacturing readiness levels is typically 10 to 20 years. Lastly, China’s navigation market is a rather captive one. Thus, it is the main platform integrators that grant Chinese market access.

DD: What is Safran’s strategy on export regulations like ITAR and ITAR-free to better address the US and other global markets?

YL: Safran complies with international law and national export regulations. Our products are designed in accordance with national law provisions and are ITAR-free. Regarding the US and export control regulations, Safran addresses this market through local subsidiaries. Strengthening our local footprint to adhere to local markets is a key enabler to capture more market volume.

DD: What can we expect from Safran in the next couple of years in the high-end inertial business?

YL: Just like tech companies did in the early 2000s in processor technologies, Safran has initiated the development of multi-core technology in lightweight multi-platform equipment.
Capitalizing on in-house expertise built with HRG Crystal’s development and production, Safran’s efforts in MEMS technologies have led to record-breaking performance.
Safran seeks to increase its navigation system performance while monitoring progress made in quantum technologies.


Yan Lenoir Safran 2020

Upon his graduation in 2000, Yan Lenoir joined Safran Group as navigation technologies engineer. For the next seven years, he has worked on the development of the then new HRG-based compact inertial core of the HAMMER guidance kit. Capitalizing on the success of this development, Yan has then worked on the integration of HRG-based inertial gyroscopes in space telecom satellites in partnership with ESA and CNES. After a 3-years long experience in avionics and helicopters programs, Yan has ultimately taken the lead of the navigation programs department of Safran Electronics & Defense’s Defense Division with the objective of speeding up the worldwide deployment of HRG Crystal based products.”


Dimitrios Damianos - Yole Développement

Dimitrios Damianos, PhD, is a Custom Project Business Developer and Technology & Market Analyst at Yole Développement (Yole).
Fully dedicated to photonics & sensing activities, Dimitrios supports the development of strategic projects, following Yole’s leading customers within the semiconductor industry. In parallel, he plays a key role in the expansion of Yole’s market & technical knowledge, maintaining long term relationships with key accounts and ensuring their expectations are met.
As a Technology & Market Analyst in imaging and sensing, he oversees the day-to-day production of valuable technology & market reports and custom consulting projects.
Dimitrios also regularly presents and delivers keynotes at international conferences and exhibitions. In addition, he has authored and co-authored several technical & market reports as well as scientific papers in international peer-reviewed journals.
Dimitrios holds a BSc in Physics and MSc in Photonics, both from the University of Patras (GR), as well as a PhD. in optics & microelectronics from the University of Grenoble-Alpes (FR).

Related reports

High End Inertial 2020 - Yole Développement

High-End Inertial Sensors for Defense, Aerospace and Industrial Applications 2020
High-end inertial sensors are still the backbone of systems that will enable autonomous transportation and the new space industry despite COVID-19.

AASM: Armement Air-Sol Modulaire (French guided munition. Translation : Air-Ground modular armament)
ADIRU: Air Data Inertial Reference Unit
CVG: Coriolis Vibratory Gyroscope
C-SWaP: Cost, Size, Weight and Power
DARPA: Defense Advanced Research Projects Agency (USA)
FOG: Fibre-Optic Gyroscope
HAMMER: Highly Agile Modular Munition Extended Range
HRG: Hemispherical Resonating Gyroscope
ITAR: International Traffic in Arms Regulations (USA)
MEMS: Microelectromechanical systems
MRL: Manufacturing Readiness Level
MTBF: Mean Time Between Failures
RLG: Ring Laser Gyroscope
TRL: Technology Readiness Level