∙ Device receives satellite signals to calculate wearer's position, then relays it to the appropriate party

• ∙ Highly accurate

• ∙ Covers large areas

• ∙ Requires clear path/unimpeded signals

∙ Enable virtual boundaries that trigger an alert when crossed

∙ Speed and accuracy can be augmented with Assisted GPS or Bluetooth technology

∙ Examples: GPS Smart Shoe, Tracking System Direct wristwatch, Comfort Zone mobile phone, Keruve wristwatch and receiver, Project Lifesaver Protect, and Locate digital watch and receiver

∙ Device emits radio waves to a locating antenna

• ∙ Signal detectable on ground or by air

• ∙ Receiver must be tuned to the appropriate frequency

• ∙ Limited signal range

∙ Can be manually activated or used to create a virtual boundary

∙ Radiofrequency identification creates a “tag” to track individuals each time they pass through an area

∙ Examples: Project Lifesaver locating device, LoJack Safety Net

∙ Device connects to the network and communicates with cellular towers

∙ Connects with the closest tower to conserve power

∙ Assisted GPS combines cellular and satellite positioning