Abstract: Due to their high mobility and rapid deployment, unmanned aerial vehicles (UAVs) can significantly expand the coverage of covert communication by relay-assisted methods in complex military confrontation areas. However, traditional UAV relay-assisted covert communication suffers from low transmission rates over long distances due to covert constraints. To this end, this paper proposed a position optimization method for dual-UAV double-assisted covert communication. While employing one UAV as a relay to forward covert signals, this method introduces an additional UAV as a friendly jammer to increase the uncertainty at the detector. Specifically, a dual-UAV double-assisted covert communication model was built, the detection error probability of the detector under this model was analyzed, and the covert constraint was derived. Then, the block coordinate descent (BCD)method was employed to jointly optimize the positions of the jamming UAV and the relay UAV under covert and transmission power constraints, aiming to maximize the system’s covert transmission rate. Simulation results demonstrate that the proposed method can significantly improve the covert transmission rate compared to existing methods.

Key words: covert communication, unmanned aerial vehicle (UAV), active jamming, block coordinate descent (BCD), position optimization