Cooperative Multi-UAV Search for Prioritized Targets Under Constrained Communications

Highlights: What are the main findings? A CHTS-CC algorithm is proposed to address inconsistent global perception, high communication load, and delayed response to critical targets in multi-UAV systems. The algorithm integrates the CCIF-ET method and a two-stage DPTA mechanism to enhance search efficiency and responsiveness under dynamic network topologies and limited communications. What are the implications of the main findings? The proposed algorithm improves UAV coordination under constrained communications, with CCIF-ET increasing environmental awareness. It is well-suited for dynamic, self-organizing networks and low-altitude areas affected by interference or obstructions. The DPTA mechanism enables UAVs to prioritize high-value or emergent targets, improving mission effectiveness in complex communication environments. This supports reliable UAV swarm operations in communication-constrained and high-interference settings, including disaster relief, border surveillance, and military conflict zones, while ensuring rapid response to critical targets. Multi-UAV search missions for prioritized targets under constrained communications suffer from weak communication-decision integration, limited global perception synchronization, and delayed mission response. This paper formulates multi-UAV collaboration search as a multi-objective optimization problem to balance communication overhead and search performance. A Cooperative Hierarchical Target Search under Constrained Communications (CHTS-CC) algorithm is proposed to address the problem. The algorithm incorporates a Cluster-Consistent Information Fusion with Event Trigger (CCIF-ET) method, which enables intra-cluster information fusion. When clusters connect, a single merge that applies joint weighting by cluster scale and uncertainty reduces communication overhead. Furthermore, a Dynamic Preemptive Task Allocation (DPTA) mechanism reallocates UAV resources based on target priority and estimated time of arrival (ETA), enhancing responsiveness to high-priority targets. Simulation results show that when all UAVs and communication links operate normally, CCIF-ET reduces total confirmation time by 8.73% compared to the uncoordinated baseline and maintains a 24.43% advantage during single-UAV failures. In scenarios with obstacles, failures, and dynamic targets, CHTS-CC reduced mission completion steps by 34.78%, 32.35%, and 55.45% compared to the non-allocation baseline. The average detection time for high-priority targets decreased by 28.48%, 29.41%, and 58.82%, respectively, demonstrating the effectiveness of the proposed algorithm.