Different from the traditional omni-directional sensors

directional sensors can rotate to a few of directions according to the target sites

the targets can be covered by them more specifically.Aimed at the coverage problem for targets with directional sensors

the constraints of target priority are joined

an algorithm with the scheme of vaccine inoculation that improves efficiency of particle swarm optimization algorithm is presented to choose a minimum set of directional sensors under the constraints for all the targets.The simulation results show that compared with the present genetic algorithm for this problem

the simulation time complexity is depleted.The size of the sensors set is reduced

and the premature convergence is restrained too.