Implementation Method of Anti Electromagnetic Interference in Identical and Adjacent Frequency for the Data link of UAV

The data link, which is the most important part of unmanned aerial vehicle (UAV), is easily affected by external electromagnetic interference (EMI) in identical and adjacent frequency. To deal with the problem of EMI in frequency band, a method that is early warning and then adopts frequency hopping or other measures is proposed, according to operating frequency band of the data link, the radiation effect experiments on a certain type of UAV’s data link under different flight distance are carried out. The experimental results reveal the dynamic range of lost-link thresholds of the data link, on the basis, the suitable EMI monitoring device installed UAV is designed. Several state parameters of the data link such as error rate, receiving auto gain control (AGC) and signal to noise ratio (SNR) are described, and characteristic of the lost-link threshold and the above three parameters in early warning state and lostlink state respectively is compared and analyzed in terms of variety range, 6dB early warning or not, stability of value and correlation with interfering frequency and operating signal power. Finally, a parameter with the lowest uncertainty is determined as the prediction criterion of the data link suffered by EMI, and when external interfering signal power reaches between the early warning value and lost link threshold, the corresponding measures will be activated to protect UAV’s data link from interruption.