Geolocation ionic 2 working in background


I made a simple app with import { Geolocation } from ‘@ionic-native/geolocation’;
From what i found on google the ionic-native/geolocation is only for when the app is in active in foreground.
My app is sending lat and lng correct when is in background.
why is working also in background?
I’m asking because i was expecting to not work when the app is in background( not closed) or the phone is loked.
For working in background i was expecting to use something like ->
import { BackgroundGeolocation, BackgroundGeolocationConfig } from ‘@ionic-native/background-geolocation’;

I tested on 2 different phones a Samsung GT-S6310 with android 4.1.2 and a Lenovo A5000 with android 4.4.2.