Recently, the team of Ding Wei/Yingying Wang, researchers from the School of Physics and Electro-Optical Engineering (SOPE) of Jinan University, and the team of Zhao Xiaoming/Ro Wei/Li Maochun, researchers from the Seventy-seventh Research Institute of the China State Shipbuilding Corporation (CSG), have launched an in-depth cooperation, and have made significant progress in the field of high-precision hollow-core fiber-optic gyroscopes. The relevant results were published in Nature Communications.
"We successfully developed the world's first navigation-grade precision hollow-core fiber-optic gyroscope with a zero-bias instability of 0.0017°/h, which is nearly 30 times lower than the existing record, and the prototype has operated continuously and stably for more than 185 hours." Ding Wei, co-corresponding author of the paper, told China Science Bulletin that the landmark achievement marks China's complete leap from theoretical innovation to engineering application research in the field of hollow-core fiber optic gyroscope technology, engraving a distinctive Chinese mark for the development of global inertial navigation technology.
Inertial navigation technology uses inertial sensors (accelerometers and gyroscopes) to measure the acceleration and angular velocity of a moving body, which in turn can be extrapolated to derive state information such as position, velocity and attitude. This technology does not rely on external reference signals such as satellites, and is known as the "pearl of industry" technology in the civil and military fields. The angular velocity sensor is the key component of the entire inertial navigation system.
Compared with other gyroscopes, fiber optic gyroscopes are the most promising angular velocity sensors by virtue of their all-solid-state, fast startup, unaffected by acceleration, large dynamic range, compact structure, digital output, etc. They are able to meet the full precision requirements from consumer level, tactical level, navigation level to strategic level. Among them, the interferometric fiber optic gyroscope is currently the most successful commercial fiber optic sensor, and the global market size is expected to exceed $3.6 billion by 2033. However, due to high technological thresholds, the market is mainly dominated by a few countries such as the U.S., France, China, Israel, Japan, and Germany.
Although significant progress has been made in interferometric fiber-optic gyroscope technology, traditional solid-core optical fibers lead to high cost and energy consumption due to the sensitivity of the material (silica glass) to environmental factors such as temperature, magnetic field, glare and radiation, and the system needs to rely on complex protection and compensation mechanisms. Therefore, since the 1970s, researchers have continued to seek alternative technologies with greater environmental adaptability, mainly forming two routes: resonant fiber optic gyro and hollow-core fiber optic gyro. However, these two solutions are facing major engineering challenges and have not yet fundamentally solved the problems faced by interferometric fiber optic gyroscopes since the 1970s.
Since the concept of air-core fiber optic gyro was proposed in 2006 (only one year later than air-core fiber optic communication), this field has gradually become a research hotspot. Despite the excellent environmental adaptability of air-core fibers, the technical bottlenecks of mode spuriousness, backscattering, and polarization crosstalk that existed in early air-core fibers have long constrained the realization of their high-precision measurement performance. It is worth noting that the hollow-core fiber communication technology has achieved large-scale application, while the practical process of hollow-core fiber gyro is still lagging behind.
The research team has made a number of key contributions in the development of hollow-core fiber optic communication in China, and witnessed the complete process of hollow-core fiber optic communication technology from laboratory to application. The team members are keenly aware that the hollow-core fiber gyroscope is at a critical stage of moving from technology verification to practical application. This research has achieved two major technological leaps through a series of innovations: first, accuracy breakthrough: the first time the hollow-core fiber-optic gyroscope has been upgraded to navigation-grade accuracy (0.001°/h order of magnitude); and second, environmental stability: the temperature sensitivity has been reduced by an order of magnitude compared with that of the solid-core fiber-optic gyroscope. These breakthroughs have laid a solid technical foundation for the development of a new generation of high-precision inertial navigation systems.
