Global Positioning System (GPS) is a satellite-based positioning system. 24 GPS satellites are orbiting the earth at a very high altitude. By picking up signals from these satellites, a GPS receiver can tell the user position over the ground with relatively high accuracy up to several metres.

Several types of GPS equipment were tested, in order the decide the best in terms of precision, battery life and acceptability to the children. The GPS equipment used in CAPABLE project is small and light-weight so that children can easily wear it on their wrist all day long without feeling discomfort. It monitors children's location at set intervals and record them on its pre-installed memory in chronological order. These data subsequently is superimposed on a map to allow the researchers to track the children's spatial movements.