GPS Tracking in the Field

GPS (global positioning system/satellite) tracking is a method for determining location using global positioning satellites.  In biological applications, tracking devices are attached to animals of interest and data is collected on measurements of longitude, latitude to help determine ground speed and map paths traveled.  This system is based on 24 satellites orbiting the earth, three of which can be used to triangulate geographic location and send that information to a ground receiver.

http://www.montana.edu/gps/understd.html#GPS_Applications_in_Agriculture

http://www8.garmin.com/aboutGPS/

This technology is widely used in applications ranging from military reconnaissance to agriculture, navigation to surveying, and regularly in biology.  GPS technology is revolutionizing the way that rhinos are being surveyed and protected.  Researchers have developed a means to place tracking devices in the horns of the endangered rhinos.  Then, with the use of even cell phones, wildlife management is able to follow the animals and be alerted to suspicious behavior.

http://www.treehugger.com/clean-technology/gps-devices-installed-in-african-rhinos-horns.html