How to listen for current position

Hi community.
I was searching for the best way to listen for the current position for my whole units, in previous posts your experts told me about "avl_evts " https://sdk.wialon.com/wiki/en/sidebar/ … s/avl_evts but I don't know how to listen for the current position, I understand that we have to add my unit(s) to the session, but I can't find which flag I must provide to get current position, and also I don't know if that flags are related to this https://sdk.wialon.com/wiki/en/sidebar/ … mat/token.

Could you guide me with this? Please.
Thanks in advance.