A survey of covert UAV Communications
Tsinghua University Press
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Various roles of UAVs for covert communications.
view moreCredit: Chinese Journal of Aeronautics
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.
Journal
Chinese Journal of Aeronautics
Article Title
A survey of covert UAV communications
Autonomous shipboard landing control system for Unmanned Aerial Vehicle based on ship motion predictor
Tsinghua University Press
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The entire landing process is divided into a tracking phase and a landing phase. During the tracking phase, the UAV is maneuvered to maintain at a close distance above the ship while predicting the ship’s roll and pitch motion online. The landing phase is initiated when an appropriate QP is identified.
view moreCredit: Chinese Journal of Aeronautics
Recently, a research team led by Tao Song from Beijing Institute of Technology, China proposed a flight envelope constrained fixed-time control strategy to achieve a reliable UAV landing on a maneuvering ship. This work well balances the control requirements between precise landing position and safe landing attitude, ensuring both the steady-state performance and the transient behavior of the tracking error.
The team published their work in Chinese Journal of Aeronautics (Volume 38, Issue 8, August 2025).
“Quadrotor UAV is a typical underactuated system, making it difficult to simultaneously track the dynamic motion of a ship in all six degrees of freedom. To address this challenge, we developed a landing control strategy based on ship motion prediction. Specifically, a Sliding Data Window Auto-Regressive (SDW-AR) model was designed to predict the ship’s roll and pitch motions in real time, and then identify the Quiescent Period (QP) required for the UAV to land safely according to the prediction results. Unlike conventional fixed-structure forecast models, the SDW-AR model employs a variable-structure design. The model parameters are updated online according to the latest observed data, thus enhances prediction accuracy by adapting to recent data trends.”, said Tao Song, the corresponding author of the paper, a professor in the School of Aerospace Engineering at Beijing Institute of Technology.
The researchers designed a Barrier Function-based Non-Singular Terminal Sliding Mode Controller (BFNTSMC), which not only guarantees tracking error steady-state convergence within an identified QP, but also improves the transient performance without violating the flight envelope constraints, thus effectively suppressing the control overshoot during the touchdown phase and minimizing the risk of collision. In addition, a Fixed-Time Disturbance Observer (FxTDO) was integrated into the BFNTSMC for estimating and compensating lumped disturbances, further enhancing the disturbance rejection capability.
Since the accessibility of GNSS signal is subject to satellite coverage limitations, obstructions from the ship’s superstructure, jamming, and spoofing, Prof. Song further suggested that future work would focus on vision-based shipboard landing and on extending the proposed strategy to GNS-denied environments.
Original Source
Cheng ZHANG, Tao SONG, Hong TAO, Tao JIANG. Flight envelope constrained UAV shipboard landing control within an identified quiescent period[J]. Chinese Journal of Aeronautics, 2025, 38(8): 103463. https://doi.org/10.1016/j.cja.2025.103463.
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.
Journal
Chinese Journal of Aeronautics
Article Title
Flight envelope constrained UAV shipboard landing control within an identified quiescent period
Efficient detection of GPS Spoofing attack! BUPT team proposes a new real-time trajectory anomaly detection scheme
Tsinghua University Press
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Anomaly detection scheme of UAV under GPS-spoofing attack and real-time trajectory correction using MSSTP-OAD.
view moreCredit: Chinese Journal of Aeronautics
Civilian UAVs rely on unencrypted civilian GPS signals, making them easy prey for spoofers who broadcast slightly stronger fake satellite signals. Once the drone locks onto the counterfeit constellation it miscalculates its position and veers off mission. Existing counter-measures demand expensive multi-frequency receivers or continuous links to cellular/reference stations—requirements that are impractical for low-cost agricultural or delivery platforms.
Researchers from Beijing University of Posts and Telecommunications (BUPT) and Pengcheng Laboratory now report a lightweight, fully on-board solution in the Chinese Journal of Aeronautics (Volume 38, Issue 10, October 2025). Their Motion-State-Series Trajectory Prediction and Online Anomaly Detection (MSSTP-OAD) system reframes the problem as short-term trajectory forecasting. During an offline phase, a stacked LSTM network is trained on flight logs—straight segments, turns, climbs and loiters—recorded in the open-source SITL simulator. Each training sample is a 20-step sequence (5 s at 4 Hz) of motion-state vectors that fuse position, velocity, acceleration, attitude angles and magnetic field readings. The network learns to predict the next five positions from the past 20 states.
During flight the algorithm works in two stages:
1. Rapid screening: every small time slot constructs a lightweight motion vector and feeds it to a first ensemble model (E1) for a quick anomaly count.
2. Final decision: at the end of the detection window, a high-dimensional vector that adds LSTM-predicted positions is sent to a second ensemble model (E2) that combines MLP, SVM and histogram-based gradient-boosting tree classifiers under a strict majority-vote rule, sharply reducing false positives.
Tests on 30 000 flight segments (half normal, half with 10–100 m horizontal spoofing offsets) showed:
- Trajectory prediction R² = 0.996 (benign) / 0.994 (under attack); RMSE < 5 m even under attack.
- Detection: accuracy 0.984, recall 0.988, F1 0.983.
- After an alarm, a simple “return-to-waypoint” manoeuvre flew 26 % less extra distance than the baseline method.
The authors emphasize that current findings are simulation-based. Field campaigns employing software-defined-radio (SDR) spoofers are now under way to quantify robustness against real-world multipath, atmospheric delay, and receiver clock drift. Upcoming efforts will:
1) fuse magnetometer and barometer data to counter potential IMU spoofing;
2) apply quantization-aware training to shrink LSTM weights for minimal firmware overhead; and
3) roll out a distributed variant in which neighbouring UAVs exchange ultra-light motion digests for consensus voting—boosting resilience without revealing flight plans.
The end goal is a drop-in firmware patch for PX4 and ArduPilot that instantly retrofits existing commercial and hobby drones with a low-cost, zero-extra-hardware shield against GPS manipulation.
Original Source
Tianci HUANG, Huici WU, Xiaofeng TAO, Zhiqing WEI. Prediction-based trajectory anomaly detection in UAV system with GPS spoofing attack[J]. Chinese Journal of Aeronautics, 2025, 38(10): 103478. https://doi.org/10.1016/j.cja.2025.103478.
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.
Journal
Chinese Journal of Aeronautics
Article Title
Prediction-based trajectory anomaly detection in UAV system with GPS spoofing attack
