Unmanned Aerial Vehicles (UAVs), as small and versatile flying platforms, play an increasingly important role in various domains such as remote connectivity, environmental monitoring, disaster management, smart agriculture, and search and rescue. Owing to their low cost, high mobility, and line-of-sight (LoS) communication capabilities, UAV-based communication has emerged as an effective approach to extend coverage and improve transmission performance. However, the LoS links and the inherent openness of wireless channels expose UAV networks to significant security risks. Fortunately, covert communications can achieve a higher level of security by hiding the very existence of transmission behavior. When wardens do not detect the transmitted signals, they will not attempt to decode the confidential content and take further action. Therefore, the information security of transmitters can be guaranteed.
In a recent article featured in the Chinese Journal of Aeronautics (Volume 38, Issue 10, October 2025), Dr. Fangtao Yang et al. conducted a comprehensive survey on covert UAV communications, providing insights into emerging methods, technologies, and applications of covert transmission in UAV-assisted networks.
This survey aims to provide an overview of the state-of-the-art in the uncertainties, wireless techniques, and applications of covert UAV communications. Firstly, although the average number of bits covertly transmitted per channel use is theoretically asymptotic to zero in the context of square root law, the positive covert rate can be achieved via the uncertainties towards wardens. Thus, uncertainties can be regarded as a higher degree of freedom to satisfy the covertness requirement since they can confuse wardens to ascertain if the transmitters are performing the wireless transmission. Existing uncertainty techniques for covert UAV communications can be classified into four categories: background noise uncertainty; power uncertainty; channel uncertainty; location variation and gaussian signaling. Secondly, since the LoS channels can benefit wardens, one common scheme to maintain the covertness is to jointly design the power and trajectory of UAV. In addition, several wireless techniques introducing uncertainties at wardens can be investigated to achieve better communication performance while ensuring the covertness. These techniques include multiple antennas, reconfigurable intelligent surface, multiple access, mmWave and Terahertz, AN as well as artificial intelligence. Finally, for the explosive applications in 6G networks, the covert UAV communications as a promising candidate can achieve full coverage and high security, as it not only can prevent the wardens from detecting the information transmission but also improve the communication performance via the mobility of UAVs. In this section, a comprehensive review of existing applications in covert UAV communications is provided. These applications include visible light communications, Internet of Things (IoT) networks, ultra-reliable and low-latency communications and backscatter networks.
However, there still remain some challenges regarding the practical scenarios and emerging applications. Thus, we point out the key issues of covert UAV communications for future research as follows. 1）Imperfect channel state information. 2) Energy efficiency; 3) Cellular-enabled UAV networks; 4) Spectrum prediction; 5) Heterogeneous interference. These issues are urgently addressed. With the rapid evolution of wireless technologies, methodologies for covert communications should evolve to introduce additional uncertainty and adapt to new security requirements in emerging applications and scenarios. This is particularly crucial to counteract the increasing computational capabilities of potential adversaries. As a result, covert UAV communications are anticipated to undergo rapid development and be widely adopted in practical applications.
Original Source
Fangtao YANG, Xiaoqi QIN, Shiqi GONG, Na DENG, Chengwen XING, Nan ZHAO. A survey of covert UAV communications[J]. Chinese Journal of Aeronautics, 2025, 38(10): 103493. https://doi.org/10.1016/j.cja.2025.103493.
About Chinese Journal of Aeronautics
Chinese Journal of Aeronautics (CJA) is an open access, peer-reviewed international journal covering all aspects of aerospace engineering, monthly published by Elsevier. The Journal reports the scientific and technological achievements and frontiers in aeronautic engineering and astronautic engineering, in both theory and practice. CJA is indexed in SCI (IF = 5.7, Q1), EI, IAA, AJ, CSA, Scopus.
