Algorithm 1: CP Estimation on $\mathit{L}\mathit{O}\mathit{S}\mathit{L}\mathbf{\left(}\mathit{i}\mathbf{\right)}$ based on the Least-square-error Method.

Initialization: Obtain the coordinates of all wireless sensor nodes, as well as the topology information of all LOSLs, that is, their formulas.

Step 1. Launch the algorithm when $LOSL\left(i\right)$ is triggered; Step 2. List all the segments on $LOSL\left(i\right)$ and obtain the coordinate set of each segment; Step 3. Find the unique possible segment where the CP may be located by using the LOSL triggering sequence; Step 4. Set the middle point of the unique possible segment as the CP.