You cannot force location services to stay on. The iPads/Apple can not do this due to privacy concerns. You can turn it on on the iPads, but it can be turned off by the user.
However - in LOST MODE feature of Meraki console (like you can do for Find My Device for other Apple products with AppleID) you can trigger the iPad to lock, force the iPad to ring to help locate, and at this time you can prompt it to send GPS coordinates to help locate. This will show up on the Meraki console map.
When device is found/returned you have to turn off LOST MODE to be returned to normal functioning by user.