无人机数据链带内连续波电磁干扰效应研究

数据链是无人机的重要分系统，是确保无人机实现地空通信的关键一环，但容易受到外界电磁干扰的影响而发生通信中断甚至硬件损伤.针对某型无人机数据链的前门耦合电磁敏感特性，对数据链设备进行电磁干扰的等效注入试验，研究了单频和双频电磁干扰对数据链的效应规律，得到了数据链敏感频点的失锁阈值以及误码率和信噪比的变化趋势.研究表明:由于大功率干扰信号通过自动增益控制电路，在射频前端降低了中频工作信号的输出功率，导致数据终端信噪比降低、误码率上升；当双频干扰均位于带内时，与单频干扰相比，在射频前端对工作信号增益的压缩作用更强，导致失锁时双频干扰中的任意一个干扰功率均低于只有单频干扰时的阈值，表明数据链带内干扰存在多源非线性增强效应. 

Research on In-Band Continuous Wave Electromagnetic Interference Effect of Unmanned Aerial Vehicle Data Link

Data-link is an important sub-system of unmanned aerial vehicle (UAV) and a key link to ensure the UAV air-ground communication. However, it is easy to be affected by external electromagnetic interference, leading to communication interruption and even hardware damage. Based on the front-end coupling electromagnetic sensitivity of a certain UAV data link, an equivalent injection test was carried out. The effect law of single frequency and dual frequency electromagnetic interference on data link were studied, and the loss-of-lock threshold of the sensitive frequency points of the data link and the changing trend of the bit error rate and the signal noise ratio were obtained. The results show that:due to the high-power interference signal passing through the automatic gain control (AGC) circuit, the output power of the intermediate frequency (IF) useful signal is reduced in the radio frequency (RF) front end, resulting in a reduction of signal noise ratio (SNR) and an increase in the bit error rate (BER) in data terminal. When the dual-frequency interference is both in-band, the compression effect on the gain of useful signal at the front end is stronger than that of the single-frequency interference. Therefore, when the data-link is out of lock, the threshold of any one of the dual-frequency interference is lower than that of the single-frequency interference, which indicates that a multi-source nonlinear enhancement effect exists in the in-band jamming.