Ultra-high Precision Quantum Inertial Navigation Technology
- Chinese keyword
- Atomic gyroscopes, quantum inertial navigation systems
- English keyword
With the establishment of Beidou system in China and various GNSS systems in the world, navigation and location service have become the fields of rapid development in geodesy in recent years. However, the non-autonomous navigation and positioning method widely used at present, which relies on receiving external source signals, has its limitations. First, it depends on navigation satellites. Once the satellites are destroyed, the system will fail. Second, it is difficult to realize indoor underwater, underground and canyon positioning. Based on this, people have developed an autonomous inertial navigation and positioning system, but the traditional technology has low accuracy due to the large zero drift of inertial gyro. Therefore, it is very necessary to develop a high-precision inertial navigation system that does not need to rely on GNSS, is not limited by geographical environment, and has long-term positioning.
Since this century, With the rapid development of quantum technology, Atomic gyro technology based on this has gradually developed. Theoretically, its zero bias stability can reach 10-8-10-10/h, which is 4-6 orders of magnitude higher than the current highest precision gyroscopes. It is the development direction of the next generation of ultra-high precision gyroscopes. It is expected to be applied to strategic nuclear submarines in the future and used to build long-endurance ultra-high precision quantum inertial navigation systems that do not rely on satellite navigation.
Ultra-high precision atomic gyroscopes are divided into atomic interference gyroscopes and atomic spin gyroscopes.
In 2003, the Advanced Program Research Agency (DARPA) of the U.S. Department of Defense launched a program called "Precision Inertial Navigation System" (PINS), which regards atomic inertial sensor technology with cold atomic interference technology as the core as the next generation of dominant inertial technology. Under the support of PINS program, AOSense Company of the United States and Kasevich Team of Stanford University jointly developed a mobile inertial sensing system integrating single-axis accelerometer, single-axis gyroscope and gravity gradiometer. The main body size is less than 1 m3, the zero bias stability is better than that, and the drift of the demonstration system reaches 5 m/h under the condition of real-time compensation. Since then, DARPA has further integrated and miniaturized atomic gyroscopes. In addition, AOSense has produced a small commercial cold atomic gravimeter in 2010, measuring noise of 1g/Hz. In 2003, the "Space High Precision Atomic Interferometry Program" (HYPER) launched by the European Space Agency (ESA) was the first satellite mission using high precision atomic inertial technology and was scheduled to be launched in 2020. Two double-loop atomic gyroscopes composed of four atomic interferometers measure acceleration and rotation angular velocity in two orthogonal directions. The two atomic gyroscopes work in different modes by controlling the velocity of atoms through laser, and realize gyroscopes with sensitivity of sum and accelerometers with sensitivity of sum respectively. With the support of the plan, the sensitivity of the atomic inertial sensor developed by the Institute of Quantum Optics of Hanover University in Germany has reached, and that of the atomic inertial sensor developed by the Paris Observatory in France has reached.
Atomic spin gyroscope started slightly later than atomic interference gyroscope, but its development speed is very fast. In 2002, Princeton University discovered the spin-free exchange relaxation (SERF) state of atoms. The coherence of atomic spins can be improved in SERF state, thus greatly improving the signal-to-noise ratio of devices. In 2005, Princeton University set up a SERF atomic spin gyro research platform for the first time, achieving a gyro bias stability of 0.04 °/h and drift in 2011. In recent years, some U.S. Companies have also started the development of SERF atomic spin gyroscope prototypes. Among them, Twinleaf Company contacted and obtained the support of the U.S. Department of Defense. It completed the development of high-precision principle prototypes from 2009 to 2010, and completed the development of miniaturized biaxial atomic spin gyroscope principle prototypes of magnitude from 2010 to 2012, with a volume of less than 8 cm × 10 cm.
The research on high-precision atomic gyroscopes in China started relatively late. In the past, the research work in the field of atomic interference technology and atomic spin polarization was mainly concentrated in the basic research field, and rarely involved in the research of inertial application. In recent years, with the upsurge of foreign research, follow-up research has begun to appear. Compared with the development of foreign technology, the overall situation lags behind by one research stage, but the gap is rapidly narrowing.
In the field of atomic interference gyro technology, the main research institutes in China include Tsinghua University, Wuhan Institute of Physics, Chinese Academy of Sciences, Beijing University of Aeronautics and Astronautics, Huazhong University of Science and Technology and Zhejiang University. Wuhan Institute of Physics, Chinese Academy of Sciences, is mainly engaged in the development of pulse fountain type cold atomic interference gyroscopes and gravimeters. It is the first unit in China to start research in the technical field of atomic interference gyroscopes, achieving zero bias stability better than 0.2/h. Tsinghua University proposed an independent continuous measurement scheme for cold atomic beams, and took the lead in realizing interference signals based on continuous cold atomic beams in the world, achieving zero bias stability better than 5/h. At present, this scheme has been extended to the research work of atomic interference gravimeters and gravity gradiometers. Beijing University of Aeronautics and Astronautics has developed a cold atom interference gyro based on cesium atom magnetic guidance, which achieves better sensitivity than.
The research on SERF atomic spin gyroscopes in China started a little later, mainly represented by Beijing University of Aeronautics and Astronautics. In 2008, Beihang began to carry out exploration and research on SERF atomic spin gyroscopes. In 2011, it realized the effect of atomic spin gyroscopes for the first time in China. In 2015, it completed the development and testing of the second generation principle prototype of SERF atomic spin gyroscopes, with a volume of less than 0.05 m3 and a zero bias stability of better than 0.05/h.
With the rapid development of global quantum technology, The difficulties and challenges in developing ultra-high precision quantum inertial navigation technology lie in: Complete the breakthrough from laboratory prototype to practical high-precision inertial measurement equipment, further improve the integration level, measurement accuracy and long-term stability of atomic inertial devices, and realize the miniaturization and integration of quantum inertial navigation systems, thus meeting the diversified needs of various users.
In view of the country's great demand for the development of ultra-high precision strategic gyroscopes and the technical blockade of high precision gyroscopes abroad, it is necessary to carry out key research and key technology research on ultra-high precision quantum inertial navigation technologies based on atomic interference gyroscopes, atomic spin gyroscopes, atomic accelerometers, atomic clocks, etc.
The breakthrough of ultra-high precision quantum inertial navigation technology can overcome the disadvantages of the existing inertial navigation system errors accumulated over time, and provide China's strategic submersible with completely passive autonomous, long-range/long endurance, safe concealment, all-weather and ultra-high precision navigation and positioning system free from external environment restrictions, which has great strategic significance.
Integrated quantum inertial measurement equipment can also be used in various carriers such as precision weapons, underwater unmanned underwater vehicles, ships, aircrafts, satellites, etc. It does not rely on GNSS to provide extremely precise long-term navigation and positioning information in various restricted geographical environments such as underwater, underground, tunnels, canyons, etc.
Atomic interference technology can also be used for precise gravity/gravity gradient measurement on the ground and in space, which will greatly improve the accuracy of gravity field measurement and is of great significance to geodesy, geodynamics research, orbit determination of space vehicles, resource exploration, deep earth exploration, etc.
In addition, atomic interference technology can also be used to measure gravitational constant and fine structure constant, and provides a new way to verify the weak equivalence principle.