SPOT

• 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/

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