The front of the AngelSense GPS 1 device has two LED lights as indicators:
Green LED light – Only flashes when there is no cellular reception, remains off otherwise.
Blue LED light – Flashes when there is no GPS reception, stays on continuously when the device is charging (will not indicate GPS reception while charging), and remains off otherwise.
Both will turn on when one of the front buttons (SOS/call) are pressed to indicate the device is on. See: Device on indication