Lateral wave plays an important role in electromagnetic (EM) wave propagation in layered conducting media. The full utilization of lateral wave in marine layered media may provide an innovative way of trans-media wireless communication. However, the existing approaches for solving lateral wave are tedious and complicated. In this letter, a simple model was presented to obtain lateral wave and other EM components in marine layered media. The model based on vector potential has simple process, definite physical meaning and high accuracy. The theoretical computations were compared with the experimental data on sea. The good agreement of the two results verified the rationality and reliability of the model. In addition, the lateral wave near the sea surface was investigated theoretically and experimentally. The results show that lateral wave has a good performance of propagation from seawater to air. The present approach is more concise and the results can gain more physical insight relative to applying asymptotic expansion methods.

Electromagnetic (EM) waves are one of the important carriers to realize information exchange between nodes in underwater wireless sensor networks (UWSNs). Building an accurate channel model is conducive to promoting the application of underwater electromagnetic communication (UEMC) in UWSNs. However, due to the complexity of the computational process, most of the channel models in existing studies are too simple to accurately represent the channel characteristics. Therefore, a new medium- and long-range UEMC channel modeling method based on the Goos–Hänchen (GH) shift is proposed in this paper. In this work, the process of medium- and long-range propagation of underwater EM waves was explained, and the attenuation of underwater EM fields under different paths was analyzed. The expression of the underwater EM field components was obtained, and its accuracy was verified. A medium- and long-range UEMC channel model was established based on the obtained EM field, and the channel response and path loss were obtained. The simplified formulas suitable for ocean engineering were given for the first time, and the impact of parameters on the channel was analyzed. The results show that the medium- and long-range UEMC is affected by communication frequency, EM parameters, seawater depth, and node location at the same time. The studies in this work are helpful for the deployment of nodes and the selection of communication frequencies in UWSNs.

Underwater electromagnetic (EM) waves are one of the important carriers for information exchange in seawater. It is necessary to study the propagation characteristics to ensure their application in seawater. However, the existence of the underwater radiation source makes the amplitude coefficients in the seawater layer vary greatly, which increases the difficulty of solving the underwater EM field. There are no good targeted solutions carried out in existing studies. In this letter, a new efficient method is proposed to solve the underwater EM field generated by radiation sources in seawater. This method divides the EM field in seawater into the secondary field and the background field. The effects of singularities produced by radiation sources are overcome, and the difference between the amplitude coefficients in the solution equation is reduced by discarding the use of amplitude coefficients from the radiation source. Except for the background field, the method does not require more additional calculations and space compared to traditional methods. Underwater EM fields can be obtained with lower computing resources and shorter computing time. In addition, experiments and numerical simulations were conducted to verify the accuracy, efficiency, and universality of this method. The results show that this method is superior to the traditional method in both efficiency and accuracy.

Electromagnetic (EM) waves are one of the important carriers for information exchange in seawater. The EM parameters of seawater are important factors that affect the performance of EM wave propagation. In the real marine environment, non-constant EM parameters make it impossible to consider seawater as a homogeneous media in the model. However, there are few targeted analyses in the existing studies. In this paper, an N-layered media model was established to investigate the influence of non-constant EM parameters on EM wave propagation in seawater. A direct global matrix method is proposed to solve the EM fields, whose result accuracy does not decrease with the increasing number of layers. The necessity and correctness of the model and methods are verified through numerical simulations and sea experiments. Combined with the existing marine environment database, the propagation characteristics of EM waves in different EM parameter profiles of seawater were analyzed through numerical experiments. The results indicated that the non-homogeneous seawater has a great impact on the intensity, phase, change rate, and spatial distribution of EM waves. Furthermore, the influence is not only reflected in the underwater EM field but also in the air and increases with frequency.

Due to the stable propagation of magnetic signals in ocean and air, magnetic detection technology has become an effective means for nonacoustic detection. The magnetic anomaly signal and shaft‐rate magnetic signal radiated by underwater vehicles are currently the most effective magnetic detection signals. Existing magnetic detection methods primarily focus on studying either magnetic anomaly signal or shaft‐rate magnetic signal. However, since a target can generate both of these magnetic signals simultaneously, detecting one type may lead to the neglect of the other, reducing detection accuracy. To overcome the limitations of existing technologies, this paper presents a combined detection method for magnetic anomaly and shaft‐rate magnetic signals. The detection process is divided into magnetic anomaly signal detection based on orthogonal basis function (OBF) and shaft‐rate magnetic signal detection based on adaptive line spectrum enhancement (ALE). Especially for the detection of magnetic anomaly signal, this paper proposes a preprocessing method based on the LOESS smoothing technique, utilising noise characteristics, and combines it with the CFAR criterion for decision‐making. This approach significantly improves the detection accuracy of the magnetic anomaly signal. Finally, the simulation and experimental results show that combining magnetic anomaly and shaft‐rate magnetic signals for combined detection can effectively improve the detection accuracy.

This research study investigated the composite magnetic fields of underwater vehicles in the presence of ocean waves under varying conductivity, analyzed their spatiotemporal characteristics, attenuation laws, and influence mechanism. We integrated the modeling of three types of magnetic fields to obtain a composite magnetic field: the magnetic anomaly field generated by a ferromagnetic vehicle was simulated with a hybrid ellipsoid–dipole model, the wake magnetic field generated by its motion, and the ocean wave magnetic field generated by wind-driven waves were derived from the velocity fields. Simulation results show that the magnetic anomaly and wake magnetic fields are mainly influenced by vehicle speed, course, and diving depth, while the ocean wave magnetic field is affected by wind speed and direction. The composite magnetic field’s intensity increases with vehicle and wind speed but decreases with the increase in diving depth. This study offers a comprehensive analysis of the composite magnetic fields of underwater vehicles in the presence of ocean waves, emphasizing the significant impact of vehicle motion and marine environmental parameters. These insights are essential to gaining a deeper understanding of the magnetic fields generated by underwater vehicles as they navigate ocean waves.