1. A indoor/outdoor positioning system, comprising: a plurality of geo telemetry units (GTUs), each GTU containing: a global positioning system (GPS) satellite receiver, a a radio-frequency (RF) transceiver, and a microcontroller (MCU) in electronic communication with the GPS receiver and RF transceiver, each MCU being operative to perform the following functions: (a) automatically determine the absolute position of the GTU based upon GPS if GPS signals are available; (b) if GPS signals are not available, automatically communicating with other GTUs to determine its position relative to at least three other GTUs using RF ranging; and (c) automatically communicate its location to other GTUs, regardless of whether position was determined through GPS or RF ranging.