# Research Progress of Dynamic Measurement Technology of Atom Gravimeter
## 4 Application Direction of Dynamic Measurement
### Navigation  
An atom gravimeter is used in the field of navigation, which can collect high-precision gravity field information through real-time measurement, match it with the pre-measured gravity map database, and obtain the position information of the carrier, i.e., gravity-matching positioning. In addition, real-time and high-precision gravity field information can also directly improve mechanical arrangement and restrain inertial navigation error divergence, i.e., gravity compensation. The two are collectively referred to as gravity-assisted inertial navigation, which uses gravity information to improve the performance of inertial navigation from different aspects so as to realize the inertial navigation retuning under the condition of GNSS rejection, correct the error divergence with time, and improve the long-term stability. The advantage of gravity-assisted inertial navigation lies in its strong concealment and the fact that there is no need to transmit or receive external signals, so it is a veritable passive navigation system. Compared with the commonly used relative gravimeter, the advantages of an atom gravimeter are high precision, no drift, and no need for regular return correction. These characteristics provide a guarantee for underwater navigation with high precision and long voyages. However, the realization of gravity-assisted inertial navigation requires not only high-precision gravity measurement equipment, which is currently available, but also high-precision, high-spatial-resolution gravity reference maps and reliable matching algorithms. At present, there is no global ocean gravity reference map with a hundred-meter-level spatial resolution that meets the requirements of underwater navigation [64], so gravity-assisted inertial navigation cannot be fully applied. It is expected that after the completion of large-area, high-precision gravity mapping in the future, the advantages of atom gravimeter dynamic measurement can be brought into full play in gravity-assisted inertial navigation. Moreover, although most of the current atom interferometers are designed to be sensitive to acceleration in one direction, there is no fundamental limit to extending them to two- or three-dimensional measurement. Therefore, many researchers are committed to using quantum inertial sensors instead of traditional sensors to solve the problem of inertial navigation system error divergence with time and realize drift-free inertial navigation systems. In 2006, [PERSON] et al. developed an inertial navigation system measured entirely by atom interferometers. The atom cloud is emitted in a parabolic trajectory and interacts with the top Raman light, with four configurations providing measurements of angular velocity and acceleration in three directions. The angular velocity resolution was 1.4 \(\times\) 10\({}^{-7}\) rad/s (600 s), and the acceleration resolution was 64 uGal (600 s) [2]. In 2014, [PERSON] et al. demonstrated a dual-axis accelerometer and gyroscope, using two magneto-optical traps a few centimeters apart to trap atoms alternately, achieving a high data rate of 50 to 100 measurements per second with a sensitivity of 0.9 mGal/Hz\({}^{1/2}\) and 1.1 (urad/s)/Hz\({}^{1/2}\)[65]. The laboratory iXAtom, which is a collaboration between France's iXBlue and LP2N, aims to build an autonomous inertial device that does not rely on external correction. In 2016, the lab demonstrated a compact multi-axis atom interference accelerometer with a sensitivity of 230 mGal/Hz\({}^{1/2}\) in the normal gravity and microgravity environments of parabolic aircraft [66; 67]. In 2019, the team's [PERSON]. [PERSON] et al. proposed a method to manipulate atom wavepackets in multiple spatial dimensions. Two-dimensional interference can separate the acceleration components in two directions and the angular velocity component in one excitation, and the two-dimensional interference superposition of three orthogonal planes can measure the acceleration and angular velocity of three axes.