## 3 The Impact of the Electromagnetic Interference on Drones
### Influence of Electromagnetic Interference of Converter Station on UAV Communication
#### 3.1.1 Impact on UAV Data Link Communication System
Commonly used diversity reception, equalization transformation and channel coding to overcome. Under the broadband interference of the converter equipment, whether the multipath effect has any special effects, and the application performance of the anti-fading technology is still unclear, and further experimental observation is needed. Although the electromagnetic spectrum space exists objectively, the current UAV does not have the ability to identify electromagnetic interference, let alone determine whether the interference frequency will fall within the working frequency band, and there are huge security risks [20]. If the data link is interfered, it may cause the UAV to lose connection or even crash out of control. If it affects the power transmission equipment, it will cause more serious safety accidents. Therefore, the study of the impact of electromagnetic interference on the UAV data link is very important. Literature [17] used a certain type of UAV as the test object to build a continuous wave irradiation test system, and found the interference effect through electromagnetic irradiation. The result found that the UAV main remote-control data link is easily affected by high-frequency continuous wave interference. The lower the frequency, the larger the loss-of-lock sensitivity threshold. The single-frequency continuous-wave will interfere with the UAV's main remote-control data link, which is manifested as a loss of lock phenomenon. At this time, the ground control station loses control of the UAV [17]. The continuous wave electromagnetic radiation effect test system for UAV (Figure 3) has three module: continuous wave radiation emission system, subject (the tested UAV), and dynamic monitoring system (Table 2). In addition, based on the analysis of the UAV body structure, it can be seen that electromagnetic interference may have an effect on the UAV main remote-control data link through the following four channels [23]. 1. The main remote-control antenna is the aircraft signal receiver. The antenna has the strongest signal receiving capability within the normal working frequency band of the UAV. Therefore, the same frequency interference can easily affect the demodulation of the digital circuit, resulting in an excessive bit error rate. It will receive interference signals with a certain energy, and the duplexer is the only way for interference current conduction, and its filtering attenuation ability directly affects the working state of the subsequent circuit. 2. In order to carry more mission loads while satisfying the purpose of lightness of the fuselage, the fuselage of the UAV generally uses composite materials. Electromagnetic waves can easily pass through the fuselage shell and enter the cabin, which increases the complexity of the internal electromagnetic environment. 3. In order to achieve the purpose of structural connection and ventilation, the surface of the fuselage has different degrees of holes, openings and other electrical unconnected parts, which are likely to cause electromagnetic leakage. \begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt}} \hline \hline
**Module** & **Function** \\ \hline Continuous wave radiation emission system & Launch an electromagnetic wave with adjustable parameters to the subject to radiatly interfere with the UAV data link \\ \hline Subject (the tested UAV) & Place in an open area during normal work, and check the working status under interference \\ \hline Dynamic monitoring system & Monitor the ground control station’s telemetry display window to report information, and use the “lost lock” phenomenon as the evaluation criterion for continuous wave electromagnetic interference on the data link. The loss of the main uplink channel means that the ground control station cannot send control commands to the drone and the aircraft is out of control, If the downlink telemetry link loses lock at this time, the drone will completely disappear from the ground control station’s “view” \\ \hline \hline \end{tabular}
\end{table}