Algorithm 1 Pseudocode of the localization-aggregation method

Input: Points indicated by used methods with timestamps: GPS $\{(x_{GPS}^1,y_{GPS}^1),\dots ,(x_{GPS}^{n_1},y_{GPS}^{n_1})\}$; $\{t_{GPS}^1,\dots ,t_{GPS}^{n_1}\}$, WLAN $\{(x_{WLAN}^1,y_{WLAN}^1),\dots ,(x_{WLAN}^{n_2},y_{WLAN}^{n_2})\}$, $\{t_{WLAN}^1,\dots ,t_{WLAN}^{n_2}\}$, BLE $\{(x_{BLE}^1,y_{BLE}^1),\dots ,(x_{BLE}^{n_3},y_{BLE}^{n_3})\}$, $\{t_{BLE}^1,\dots ,t_{BLE}^{n_3}\}$, distributions of errors of GPS ($f_{GPS}$), WLAN ($f_{WLAN}$) and ($f_{BLE}$), present timestamp t Output: Coordinates of the optimum with value of function $\mathrm{\Phi }(x,y)$ (Equation (10))  Calculate range of calculations: $x_{min}=min\{x_{GPS}^1,\dots ,x_{GPS}^{n_1},x_{WLAN}^1,\dots ,x_{WLAN}^{n_2},x_{BLE}^1,\dots ,x_{BLE}^{n_3}\}$, $x_{max}=max\{x_{GPS}^1,\dots ,x_{GPS}^{n_1},x_{WLAN}^1,\dots ,x_{WLAN}^{n_2},x_{BLE}^1,\dots ,x_{BLE}^{n_3}\}$, $y_{min}=min\{y_{GPS}^1,\dots ,y_{GPS}^{n_1},y_{WLAN}^1,\dots ,y_{WLAN}^{n_2},y_{BLE}^1,\dots ,y_{BLE}^{n_3}\}$, $y_{max}=max\{y_{GPS}^1,\dots ,y_{GPS}^{n_1},y_{WLAN}^1,\dots ,y_{WLAN}^{n_2},y_{BLE}^1,\dots ,y_{BLE}^{n_3}\}$. Find a point $(x,y)$ where $x\in [x_{min},x_{max}]$, $y\in [y_{min},y_{max}]$, with the maximum value of evaluation function $\mathrm{\Phi }(x,y)$ (10) according to the grid method, local search, or another optimization method.