Algorithm 1 Virtual Lattice-Based Monitor Algorithm

1:Input: ${\mathcal{S}}_{SN}=\left\{{\mathcal{S}}_1,{\mathcal{S}}_2,\cdots ,{\mathcal{S}}_c\right\}$, the position of all SNs 2:${\mathcal{S}}_{AN}=\left\{{\mathcal{S}}_1,{\mathcal{S}}_2,\cdots ,{\mathcal{S}}_n\right\}$, the position of all ANs 3:With GAF, a cuboid is partitioned into many virtual small lattices, their ID set is denoted by $\mathcal{I}=\left\{{\mathcal{I}}_1,{\mathcal{I}}_2,\cdots ,{\mathcal{I}}_m\right\}$. 4:for $i\in \mathcal{I}$, $(i=1$, 2, ⋯, $m)$ do 5: AN ${\mathcal{S}}_z$ locally broadcasts a HELLO message to all nodes in lattice ${\mathcal{I}}_i$ with its max transmission range. 6: if AN ${\mathcal{S}}_z$ receives a number of HELLO-ACK message which is greater than or equal to two then 7:  Record ${\mathcal{I}}_i\in \mathcal{P}$ 8: else 9:  AN ${\mathcal{S}}_z$ receives a number of HELLO-ACK message which equal to one 10:  Record ${\mathcal{I}}_i\in \mathcal{Q}$ 11: end if 12: Record center coordinates set ${\mathcal{I}}_i^{\prime }=(x_i$,$y_i$,$z_i)$. 13: end for 14:Delete ${\mathcal{I}}_i\in \mathcal{P}$ and corresponding center coordinates from ID set $\mathcal{I}$ and ${\mathcal{I}}_i^{\prime }$. 15:Record new ID set ${\mathcal{I}}_i^{\prime }\in \mathcal{I}$, new center coordinates set ${\mathcal{I}}_i^{〞}\in {\mathcal{I}}_i^{\prime }$. 16:Output: The lattices that are required to be patrolled by ANs, and the ID set is ${\mathcal{I}}_i^{〞}$.