BlueNaute™: The Revolution That Maritime Navigation Has Been Waiting For
The International Maritime Organization, through the SOLAS (Safety of Life at Sea) treaty, requires that all vessels weighing more than 500 tons be equipped with at least one gyrocompass. The purpose of this gyrocompass is to independently indicate true north. This requirement is mainly fulfilled today through the use of technology that is more than 100 years old, the mechanical gyroscope. Additionally, this technology requires periodic maintenance operations (every 12 to 18 months) and has a limited lifespan, generally 3 to 5 years. Alternative solutions have existed for about twenty years. These so-called "maintenance-free" solutions, requiring no preventive maintenance, are generally built around a fiber-optic gyroscope (FOG). Much more expensive than mechanical gyroscope-based solutions, they have never really found their place on the market, despite generally offering additional features, such as indicating roll, pitch, and heading.
The Mechanical Gyroscope
Knowing one's position, speed, and orientation is a critical need for navigating. In the 19th century, navigation was carried out using instruments like the sextant, chronometer, compass, and log. With the sextant and chronometer, the stars could be observed in order to determine the ship's precise coordinates (latitude, longitude) at sighting points. This position was then maintained until the next sighting point through so-called "dead reckoning", meaning by incorporating the speed measured by the log along the heading indicated by the compass. At the same time, in the mid-19th century, scientific works showed that a top mounted on a suspended platform made it possible to keep a direction: whenever the top was spun at a sufficient speed, its axis of rotation would remain fixed relative to the stars. This observation built upon the evidence of the earth's rotation by the French scientist Léon Foucault, in the famous pendulum experiment carried out at the Pantheon in 1851. This led to a new navigation instrument: the gyroscope (from the Greek gyros – rotation and skopein - see). The first laboratory instrument was built by Foucault in 1852, and the use of the gyroscope to indicate north no longer seemed to be a problem, at least in theory. However, it would take 50 years to create a working model. In the meantime, it was necessary to be able to keep the top spinning, which was made possible through gradual progress in the field of electric motors; developing devices to keep the top spinning in a horizontal plane independent of variations in roll, offsetting the effects of the boat's variations in direction and speed.
The work carried out by Dr Hermann Anschütz and his cousin Max Schuler led to the first gyrocompass patent in 1904, which then led to a more sophisticated model that included two gyroscopes within a sphere floating in a liquid in 1924. This technology remains the gyrocompass market leader for the merchant marine more than 100 years after the first patent, an incredibly long lifespan. Floating gyroscopes, however, have two drawbacks. The tops, which are subject to wear, must be changed every 3 to 5 years, and the liquid must be replaced once every 1 to 2 years. These two preventive maintenance operations make the overall cost of owning these gyroscopes relatively high despite a very attractive initial purchase price.
A Revolution for 21st Century Navigation: The Hemispherical Resonator Gyro, or HRG
The number and complexity of the parts involved in building a high-precision measuring device have a direct impact on its reliability and on the cost of preventive and corrective maintenance. To put this observation in simpler terms, a gyroscope's reliability is first and foremost directly proportional to how many parts it has. The HRG is made of only a few basic parts and a simple design, making it extremely reliable.
The Sagem-patented HRG gyroscope uses the inertial characteristics of the plane of vibration of a wave resonating inside a miniature hemisphere that is mechanically uncoupled from the outside world. This sturdy construction is not subject to any mechanical wear, and therefore has a virtually unlimited lifespan, unlike mechanical gyroscopes. This is why it was first used for space applications, making it the only technology that has never failed in space, with more than 18 million hours in service without even the slightest incident. The HRG is the only technology that is both "maintenance-free" and ultra-reliable.
Although the high-performance characteristics and extreme reliability are unanimously recognized by the scientific community, it was still necessary to make this technology affordable enough to be used in a civilian gyrocompass. This challenge was met by Sagem through major technical innovations and substantial industrial investments.
Sagem's BlueNaute™ System: A First at Euronaval 2012
Thanks to the HRG technology's intrinsic properties, the BlueNaute™ navigation system requires no maintenance. With an MTBF* of more than 100,000 hours, it is unrivaled in terms of lifespan, reliability, and operational uptime. Thanks to the HRG's small form factor and environmental resilience, BlueNaute™ can easily be incorporated into all types of platforms. BlueNaute™ exists in different versions to cover all of the market's needs. BlueNaute™ is therefore the ultimate "maintenance-free" solution for container ships, tankers, cruise ships, off-shore support vessels, and mega-yachts.
* Mean Time Between Failure