BLE beacon indoor positioning
BLE beacon indoor positioning uses small Bluetooth Low Energy transmitters placed through a building so a safety device can report which floor, wing or room a worker is in - where GPS cannot reach.
GPS is the backbone of outdoor location, and nearly useless four walls in. In a hospital, a corrections facility or a large store, 'the address' is not an answer - responders need the ward, the level, the room. Battery-powered BLE beacons fixed through the building broadcast identifiers; the worker's device hears the nearest beacons and reports its position against a floor map.
For duress response, the difference is minutes. An activation that says 'Building C, Level 2, East Wing' sends help to the right corridor; one that says '14 Example Street' sends help to a front desk.
Beacons are cheap, run for years on coin cells, and need no network of their own - the worker's device does the reporting. The Duress Eagle uses BLE beacon positioning alongside 4G and GPS; Phoenix reports beacon position via its paired phone.