The atomic magnetometer is currently one of the most-sensitive sensors and plays an important role in applications for detecting weak magnetic fields. This review reports the recent progress of total-field atomic magnetometers that are one important ramification of such magnetometers, which can reach the technical level for engineering applications. The alkali-metal magnetometers, helium magnetometers, and coherent population-trapping magnetometers are included in this review. Besides, the technology trend of atomic magnetometers was analyzed for the purpose of providing a certain reference for developing the technologies in such magnetometers and for exploring their applications.

An aeromagnetic survey is an important method in magnetic anomaly detection and geophysical prospecting. The magnetic field is typically measured by optically pumped magnetometers (OPM) installed on the aircraft. The measurement accuracy of the OPM is easily affected by the platform-generated magnetic fields. Therefore, aeromagnetic compensation is necessary. The traditional compensation model only considers the permanent, induced, and eddy current interference magnetic field of the aircraft platform. However, the interference field produced by the avionics system, and the relative motion between the aircraft and the magnetometer, are still not taken into account. To address this issue, we proposed a novel strategy to eliminate the additional interference of the platform with two OPMs. Among them, the OPM located farther away from the aircraft serves as a sensing magnetometer, whereas the near OPM serves as a reference magnetometer. The coherent noise suppression method is used to process the residual magnetic field interference after compensation. By establishing the interference magnetic transfer function between the two sensors, the interference field can be suppressed. The results of the experiments demonstrate the effectiveness of the novel strategy, and the standard deviation of residual interference drops from 0.065 nT to 0.045 nT.

At present, the research and application of aeromagnetic compensation are almost all based on the Tolles–Lawson (T–L) model. With the development of unmanned aerial vehicles (UAVs), the number of intelligent electronic devices in UAVs is increasing, and the magnetic environment of the platform is becoming more and more complicated. Research shows that the magnetic interference caused by airborne electronic equipment has been very significant, sometimes even reaching 100 nT. The traditional airborne magnetic compensation method based on the T–L model cannot effectively compensate the magnetic interference caused by airborne electronic equipment. Aiming at the problem of magnetic interference of airborne electronic equipment of UAVs, this paper analyzes the origin of magnetic interference of airborne electronic equipment using experiments, and it was found that it is related to the power supply current, and the characteristics of magnetic interference are similar to permanent magnet materials. Based on this feature, we eliminated the magnetic interference caused by the working current of airborne equipment by establishing a linear compensation model based on the current’s source. The experimental data show that the current interference source model proposed in this paper can effectively compensate the magnetic interference generated by airborne electronic equipment and the compensation improvement ratio (IR) is greater than 10.

Fe-based amorphous alloys have advantages of low iron loss and high effective permeability, which are widely used in sensors and actuators. Power efficiency is one of the most important indicators among power conversion applications. We compared the magnetomechancial power conversion factors of metallic glassy ribbons FeCoSiB (Vitrovac 7600) and FeSiB (Metglas 2605SA1). We investigated the crystallization process under different annealing temperatures and tested the magnetomechancial coupling factors (k) and quality factors (Q) by using resonant and anti-resonant methods. We found that the maximum coupling factor of the annealed Vitrovac ribbons was 23% and the figure of merits k²Q was 4–7; however, the maximum coupling factor of the annealed Metglas ribbons was 73% and the maximum value of k²Q was 16. We can observe that the Metglas 2605SA1 ribbons have higher values of the magnetomechanical power efficiency than those of the Vitrovac 7600 ribbons, which means they are better to be used in subsequent research regarding acoustically driven antennas.

Eliminating the magnetic interference of the carrier platform is an important technical link and plays a vital role in aeromagnetic survey. The traditional compensation method is based on the Tolles–Lawson (T-L) model and establishes the linear relationship between the aircraft interference magnetic field and the aircraft attitude. The compensation coefficients are solved by designing the calibration flight. At present, almost all aeromagnetic systems use the fluxgate magnetometer fixed to the aircraft to realize the attitude measurement of the flight platform. However, the fluxgate magnetometer has problems, such as non-orthogonal error, zero drift error, and linearity error limited by the production process, and the fluxgate magnetometer is also very susceptible to external magnetic interference as a magnetic sensor. These lead to the aircraft attitude calculated by the fluxgate magnetometer being inaccurate, thus reducing the compensation effect. In this article, we analyze the influence of the fluxgate magnetometer noise on compensation and propose a new conjunctive compensation method based on inertial navigation systems (INS) and fluxgate magnetometer information to improve the compensation effect. The flight experiment data show that the proposed method can significantly improve the quality of aeromagnetic data. Compared with the traditional compensation method only based on fluxgate magnetometer information, the improved ratio is increased by 30–60%, and it is a real-time compensation method. It shows that the proposed method has a remarkable compensation effect for aeromagnetic interference.

A miniature three-axis induction magnetometer (IM) for borehole logging was designed, manufactured and tested. The form of the proposed IM is a cube with 12 coils at edges, which are embedded in a ring cylinder. Thus, the 12 coils are placed along with X, Y and Z axis. Each axis consists of 4 coils that are connected in series. The length, inner and outer diameters of the ring cylinder are 40 mm, 43 mm and 64 mm, respectively. The weight of the IM is 450 g. The working frequency bandwidth is set within 1Hz-10 kHz. The equivalent induction magnetic noise (EIMN) level of the IM is measured as a value less than ${\rm{pT/\sqrt Hz\ @\ 100Hz}}$ for three axes. The features and the noise performances of the proposed IM shows a potential for the use of borehole logging.