Crystal clear – hemispherical resonator gyroscope is a navigation game changer

SAFRAN has developed what it believes is a game changer. The hemispherical resonator crystal gyroscope has no moving parts so is maintenance-free.

SAFRAN’s hemispherical resonator crystal gyroscope has no moving parts so is maintenance-free.

Everybody thinks they know what a gyroscope is: it spins at high speed, the whole assembly goes somewhere inside an aircraft or ship and it tells you which way is up and which way is north. And it’s probably quite big and delicate.

That may once have been true, but not any more. SAFRAN Electronics & Defense has developed what it believes is a game changer called the HRG Crystal gyro. HRG stands for Hemispherical Resonator Gyroscope; it has no moving parts so is maintenance-free.

The gyro is an integral part of a new generation of Inertial Navigation Systems (INS) that’s light, small and tough enough to be used on manned and unmanned aircraft, surface ships, submarines and guided missiles.

The product of 10 years of development and progressive miniaturisation, SAFRAN believes its HRG Crystal technology offers the highest accuracy available in the world at the lowest cost. The company’s Australian sales and marketing director, Anthony Bianco, says that in submarine applications it provides the capability you would find in a current nuclear-powered submarine at one 20th of the cost, in a package the size of half a shoebox.

The US Government’s Defence Advanced Research Projects Agency (DARPA) tested SAFRAN’s HRG Crystal technology and found, to use the industry jargon, its Size Weight and Power (SWAP) requirements are an order of magnitude lower than for any other system. For unmanned systems it provides location accuracy for its cost and SWAP needs that is unavailable elsewhere.

Every INS gyro “drifts” during a mission, but the drift of an HRG Crystal navigation system has proven to be tiny. So, if the GPS network is brought down by hostile action, a submarine or surface ship can still navigate accurately for almost a month without needing any external reference. And its guided weapons can still function as advertised.

Furthermore, if the ADF wanted to jam hostile GPS signals in contested areas, the navy, RAAF and army could still operate there safely if they had this technology on-board, Bianco says.

“We have seen this extensively in Ukraine where ‘navigation warfare’ and the jamming of GNSS (Global Navigation Satellite System) signals has become so prolific that the military have had to reduce their over-reliance on GPS significantly,” Bianco says.

“There are a plethora of adverse GNSS signal events in the South China Sea and the situation continues to deteriorate in this regard.

“It’s hard to imagine a future conflict where navigation warfare won’t be prevalent.”

The INS “drift” problem was eased slightly when traditional gyros were replaced by Ring Laser Gyroscopes and then by Fibre Optic Gyros (FOGs), but SAFRAN took a conscious decision 15 years ago to focus instead on the then-nascent technology of HRG Crystals.

A small, robust gyro with no moving parts and without the complication of large fibre optic windings provides obvious advantages on the battlefield as well as the factory. Its shock and vibration resilience has seen it dominate artillery firing, targeting and pointing application markets, Bianco says.

The company’s R&D has given it a 10-year lead. SAFRAN has mastered both the technology itself and the essential miniaturisation that allows it to be deployed in a wide variety of military applications. The company’s HRG Crystal technology has now been adopted by the US DoD, French Armed Forces and the majority of NATO and allied countries.

Just one other company in the world (to Bianco’s knowledge) manufactures HRG Crystal INSs and it is based in the US. That company hasn’t managed yet to miniaturise the system but the US Department of Defence acknowledges the value of HRG Crystal technology and has acquired several thousand different systems that use it.

Here in Australia, Bianco can see emerging opportunities in the navy’s Continuous Naval Shipbuilding program as well as in upgrades to existing surface ships and submarines.

Australian military customers have also taken a keen interest in the technology for a number of autonomous platform applications, he says, and preparations are underway to extensively trial the technology.

Looking further ahead, SAFRAN believes quantum technology will provide the next revolution in Position, Navigation and Timing (PNT) systems. But these are three to 10 years away, depending on the application, Bianco says, and there are still question marks over exactly how deployable a quantum system will be, or which military applications it can succeed in.

Quantum will further enhance current navigation systems but, as Australia’s Defence Science and Technology Organisation and Defence’s own published quantum roadmaps point out, quantum advancements will not replace current inertial technologies universally. So HRG Crystals represent the leading edge of current INS technology.

“Our Defence force needs ready solutions now, which they can upgrade with quantum sensors in the future, which is exactly what we are providing,” he says.