What you need to use is some sort of a location tracking object that tracks and updates your app with the updated location. Since you are using Ionic, I believe there might be some limitations as native integrations won't be available, but you can get started here,
Background Geolocation - Ionic Documentation[
^].
Google Maps then enables you to place the markers on the map based on the location objects (LatLong objects,
Coordinates | Maps JavaScript API | Google Developers[
^]), and using this you can place the markers. Take a look at this
Google Maps' official website[
^], where they have shown a working sample code that can render the Google Maps instance with a marker.
When Ionic provides you with an update, you must update the Google Maps instance and refresh the marker—removing the previous ones and adding a new one!
Although this is not what you are looking for exactly, but this can help you understand how to capture the location updates from the maps instances and perform an action,
https://www.codeproject.com/Articles/1040389/Ok-Android-Broadcast-my-location.