US Patent 9721456 Personal hazard detection system with redundant position registration and communication

A system for monitoring the safety of personnel on a work site, by providing workers on the site with portable battery powered safety monitors equipped with alarms, sensors to detect hazardous conditions, at least two forms of geo-location and two forms of voice and data telecommunication and two CPU's sharing the computation load, each CPU equipped to monitor and reset the other in case of failure to function, with each monitor capable of serving as a node in a mesh network and relaying information concerning alarms detected including location thereof to other monitors on the mesh network.