The Silvertree Reach can obtain your loved one's location from four different connection sources.
They are:
GPS/LTE : with a subscription/membership, the Silvertree Reach will power on its GPS and LTE chips to track your loved one remotely. See How does my Silvertree Reach use GPS/LTE?
The Silvertree App : when you are close by a device with the Silvertree App, the app automatically leverages your mobile's location to preserve the Silvertree Reach’s battery life.
Wi-Fi: allows you to input your loved ones static location. Note: If you are going to a different location with WiFi, you must update your WiFi in the Silvertree app.
See here how location affects battery life.