LAUSR

When a UAV broadcasts its location periodically during flight, a target will observe the strongest signal when the UAV is at the closest location; thus, the target can infer its location based on the observed signals and the UAV’s trajectory. We consider how to design trajectories for UAVs such that all targets can locate themselves, and the maximum length of trajectories is minimized. To make the problem tractable, we impose constraints on the set of possible trajectories such that they only contain the edges of small squares. We propose an integer-linear-programming-based solution, which runs in exponential time, and two polynomial-time constant-factor approximation algorithms. We implement a prototype system to verify the feasibility of the localization method. Simulations show that our approach outperforms the existing ones in terms of flight length and localization error.