Android operating systems 6.0 and above require GPS to be turned on for searching and synchronizing Bluetooth devices (operating systems 10.0 and above require authorization to locate) to use Bluetooth.
Ref：https://source.android.com/devices/bluetooth/ble
Caution: BLE scanning needs location permissions as BLE scanning identifies objects that could be used for geolocation. Turning off Location services will turn off Bluetooth scanning.
