Notations:
G	The complete undirected graph
V	The set of all nodes
${\mathit{V}}_{\mathit{s}}$	The set of all rendezvous nodes
${\mathit{V}}_{\mathit{t}}$	The set of all rendezvous nodes
E	The set of all edges
${\mathit{E}}_{\mathbf{1}}$	The subset of edges that GV gets through
${\mathit{E}}_{\mathbf{2}}$	The subset of edges that UAV gets through
$s_j$	The service time of target j
${\mathit{t}}_{\mathit{i}\mathit{j}}$	The travelling time between nodes i and j
$\mathit{\theta }$	The maximal working time of the UAV