Students are eager to build a human tracker system in the campus. They want each person to carry a transmitter wherever s/he goes. Multiple towers will receive their signals and convey this reception to the central computer. The computer will time the arrivals with GPS unit, and locate the emitter by simple triangulation. The computer can track the location on a map for an easy display.
Students wanted to know if this was feasible. They had ideas of using high-freq dishes, radio-id tags, etc. However, I suggested them to build a system at low frequencies, which will be less prone to blockage. This is of concern, since the system will otherwise fail if the person reaches in a classroom.
We are not sure about how much of signal is needed to make it detectable at the receiving stations, but we are initially going to play with a system working over less than 300 mtrs, using simple yaggi antennas.