Algorithm 1: IPS adaptive outlier suppression algorithm

Input: Threshold $H_{head}$; $H_{position}$; Current IPS Positions $T_{Mnow}$; Current VO position $T_{VOnow}$  Step 1: Calculate the IPS positional change $\Delta T_M=T_{Mlast}^{-1}{T}_{Mnow}$, Calculate the VO positional change $\Delta T_{VO}=T_{VOlast}^{-1}{T}_{Onow}$.  Step 2: Update the previous moment’s pose data with the current pose data $T_{Mlast}$, $T_{VOlast}$.  Step 3: IPS pose change $\Delta R_M$ and displacement change $\Delta t_M$ are extracted from the change matrix $\Delta T_M$.  Step 4: VO pose change $\Delta R_{VO}$ and displacement change $\Delta t_{VO}$ are extracted from the change matrix $\Delta T_{VO}$.  Step 5: Substitute $\Delta R_M$, $\Delta R_{VO}$, $\Delta t_M$, $\Delta t_{VO}$ into the equation $S=\sqrt{{\sum }_{i=0}^m{\sum }_{j=0}^n{\left(A_{ij}-B_{ij}\right)}^2}$ respectively The error of change of heading angle eR and the error of change of displacement et.  Step 6: if $e_t\le H_{position}{e}_R\le H_{head}$.  Step 7: Add the current IPS pose $T_{Mnow}$ to the pose map.  Step 8; else.  Step 9: The current IPS pose does not join $T_{Mnow}$.