Since {HEAD ~ the location} of this smartcard wireless device can be tracked in {TAIL ~ the airport} by normal wireless antenna location means, by GPS, or by direction fixing between multiple antennas, or any other tracking means, the approximate location of the person is known at all times while in any area of the airport or building 
tracked in
Since { HEAD ~ the location } of this smartcard wireless device can be tracked in { TAIL ~ the airport } by normal wireless antenna location means , by GPS , or by direction fixing between multiple antennas , or any other tracking means , the approximate location of the person is known at all times while in any area of the airport or building
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH