- GPS satellites provide signals
- SPOT messenger's onboard GPS chip determines your GPS location and sends your location and preselected message to communication satellites
- Communication satellites relay your message to specific satellite antennas around the world
- Satellite antennas and a global network route your location and message to the appropriate network
- Your location and messages are delivered according to your instructions via email, text message, or emergency notification to the GEOS Rescue Coordination Center
http://www.findmespot.com/en/