L26-DR GNSS - $PSTMDRMMFB command (Dead reckoning)

Hi, what is the function of this command, the L26-DR GNSS Protocol Specification says “Input map match data” but I don’t know when could be useful

Thanks

The feature need an application framework where a map matching system is available (e.g. in a navigation system) ,and the module can exploit the map matched position to improve the quality of its PV output.
The map matching system of the host will compare the information output by the L26-DR, so as to inform the module the current map location and difference through the PSTMDRMMFB command. The module optimizes the PV output based on this feedback.This feature is called Map Matching Feedback (MMFB).