Automatic path planning problem is essential for efficient mission execution by unmanned aerial vehicles (UAVs), which needs to access the optimal path rapidly in the complicated field. To address this problem, a novel hybrid particle swarm optimization (PSO) algorithm, namely, SDPSO, is proposed in this article. The proposed algorithm improves the update strategy of the global optimal solution in the PSO algorithm by merging the simulated annealing algorithm, which enhances the optimization ability and avoids falling into local convergence; each particle integrates the beneficial information of the optimal solution according to the dimensional learning strategy, which reduces the phenomenon of particles oscillation during the evolution process and increases the convergence speed of the SDPSO algorithm. The simulation results show that compared with PSO, dynamic-group-based cooperative optimization (DGBCO), gray wolf optimizer (GWO), RPSO, and two-swarm learning PSO (TSLPSO), the SDPSO algorithm can quickly plan higher quality paths for UAVs and has better robustness in complex 3-D environments.

Cyber–physical systems (CPSs) are new types of intelligent systems that integrate computing, control, and communication technologies, bridging the cyberspace and physical world. These systems enhance the capabilities of our critical infrastructure and are widely used in a variety of safety-critical systems. CPSs are susceptible to cyber attacks due to their vulnerabilities such that their security has become a critical issue. Therefore, it is important to classify and comprehensively investigate this issue. Most of the existing surveys on it are conducted from a single perspective. In this article, we present a comprehensive view of the security of CPSs from three perspectives: 1) the physical domain; 2) the cyber domain; and 3) the cyber–physical domain. In the physical domain, we review some attacks that directly damage the physical components of CPSs such as sensors and discuss corresponding defenses. We also review the attacks that CPSs in the cyber domain may face and study methods to detect and defend against them. In addition, we survey the intelligent attacks faced by CPSs and the corresponding defensive means. In the cyber–physical domain, we provide an overview of attacks that come from the cyber domain and eventually damage the physical parts, and discuss the corresponding detection and defense methods. Finally, we present the challenges and future research directions. Through this in-depth review, we attempt to summarize the current security threats to CPSs and the state-of-the-art security means to provide researchers with a comprehensive overview.

Unmanned aerial vehicles (UAVs) are unmanned aircrafts operated by radio remote control and programmed control equipment. Due to their small size, low cost, and high flexibility, UAVs are widely used in military and civilian fields, such as geological detection, film shooting, traffic control, homeland security, and reconnaissance in battlefield. With the rapid increase of UAVs and the success of their related technologies, they also face many security problems, such as jamming, man-in-the-middle, and false message injection attacks. The security of UAVs has become a hot research topic. However, most UAV-related surveys are analyzed and summarized from a single perspective, there are few surveys about UAV cybersecurity. Hence, we believe that a categorized and comprehensive survey of UAV cybersecurity is urgently needed. In this paper, we present a comprehensive survey on UAV cybersecurity, from three aspects of the physical domain, cyber domain, and cyber-physical domain. Specifically, in the physical domain, we review attacks that directly affect UAVs' fuselages or their significant components and discuss the solutions to these attacks. We survey the cyber threats against UAVs and the corresponding defense or detection methods in the cyber domain. One highlight is the security threat for UAV intelligent systems and the corresponding defense methods. Finally, in the cyberphysical domain, we summarize cyber-physical attacks such as GPS spoofing, these attacks are easy to destroy the chips and sensors of UAVs. In conclusion, understanding these attacks and their associated defense mechanisms will help pave a path towards the cybersecurity of UAVs. In addition, future research directions and problems to be solved are discussed at the end of this survey. With this comprehensive literature review, we set out to provide a novel insight into the current state of cybersecurity of UAVs.