This article deals with cooperative target circumnavigation control strategy for a team of unmanned aerial vehicles (UAVs) when only range measurements are available. First, we propose novel guidance laws based solely on range measurements for tracking and cooperation. Then, convergence and stability of the proposed guidance laws are proved by a rigorous inference of mathematics. Moreover, an illustrative simulation shows that the controlled UAVs orbit around a target and maintain even spacing along the common circle, which confirms the performance of the proposed guidance algorithms.

The cooperative tracking of moving ground targets in obstacle environments by multiple fixed-wing Unmanned Aerial Vehicles (UAVs) has broad applications in both military and civilian fields. While extensive research has focused on tracking guidance laws and obstacle avoidance methods, existing approaches typically treat these functions separately. In contrast, this paper proposes a unified guidance design method that simultaneously addresses both target tracking and obstacle avoidance. The method develops a three-dimensional guidance strategy for fixed-wing UAVs under maneuvering constraints, considering the coupling of linear and angular velocities during cooperative tracking and obstacle avoidance. Comprehensive stability theory proofs are provided to ensure global asymptotic stability for the proposed method. To evaluate the effectiveness of the guidance law, simulations were conducted, including a comparative study with the artificial potential field method, where the proposed approach demonstrated superior robustness and coordination. Additionally, six-degree-of-freedom (6-DOF) simulations validated the applicability of the guidance law under realistic UAV dynamics, showing strong adaptability and realtime responsiveness.

This paper provides a method of fixed-structure μ controller design with a novel particle swarm optimization (PSO) technique. The structured synthesis problem based on optimization is formulated and solved by a kind of constrained PSO algorithm which is relatively simple and without any new parameters added in the objective function. The experimental results tested on a set of 12 benchmark functions show that the proposed algorithm can outperform others in most cases. What is more, an air-to-air missile longitudinal channel control structure based on the proposed algorithm is studied and the simulation results are compared with other algorithms. The final comparison results also show the superior performance improvement over other algorithms.

One important problem for unmanned aerial vehicles (UAVs) in mission applications is to track ground targets automatically. A major concern is how to keep the tracking process stable and efficient while the motion of the ground targets changes rapidly. In this brief, a new guidance strategy for the ground target “Search and Capture” based on a virtual target is proposed. First, a virtual trajectory, which is composed of straight lines and arcs, is generated based on the motion of the target. The straight lines are used to capture, while the arcs are used to search, and switch between straight line and arc when some condition is met; second, we design a new guidance law based on line-of-sight (LOS) which makes a UAV to track the virtual target automatically. This new method solves the following three problems simultaneously: (1) The UAV always keeps a constant speed to track the target with changing velocity, (2) the generated trajectory meets the flight constraints of the UAV, and (3) the speed range of the ground target can be from the stationary to almost the maximum cruising speed of the UAV. Simulation results show that the proposed guidance strategy can achieve stable tracking for various motions of the ground target.