STE researchers sedate an elephant from a helicopter by firing a syringe using a tranquilizer gun. They attach the GPS collar (weighing 12 kg) around the elephant's neck and wake the elephant by injecting it with an antidote.
The GPS collar transmits positional information at a predetermined time interval, which can be received on computers or mobile phones. The location data is accurate to about 5-15 meters, and most collars are set to report every hour. These data are then analyzed using a geographic information system (GIS) to learn about the elephant's home range and movement patterns.