Creation and monitoring of variable buffer zones

Abstract

A system for monitoring operation and location of a movable entity, such as a person, vehicle, movable equipment item or movable structure, at an activity site, such as a construction or mining site, that carries a location determination (LD) signal module to determine the entity's present location. When a restricted or hazardous activity occurs without warning (emergency) or is scheduled to occur at a selected location (fixed or moving) and selected time interval on the site, a buffer zone surrounding the restricted activity location is determined, and any movable entity that is within or will come within the buffer zone is advised to move or be moved elsewhere during the time the restricted activity occurs, unless the movable entity has an associated priority that is greater than an associated priority for the restricted activity. The buffer zone may vary with time in size, location and other characteristics. Complex buffer zones, resulting from overlap of two or more activated buffer zones, can also be created and monitored. Signals can be received by the LD module from sources such as GPS, GLONASS and LEO satellites, or from ground-based signal sources such as Loran signal towers.