Automatic Packet Reporting System
APRS………..A tracker! A GPS is fed into a TNC (Terminal Node Controller). The TNC takes the GPS’s NMEA data stream andconverts it to analog. Now its analog, the audio is injected into a VHF radio to be transmitted on 144.390mhz. The transmission will include your location and call sign.
There are a few ways of easily being tracked. Tinytrak is one. A good simple tracker. Thats it.
If you want a good mobile/tracker, then the Kenwood TM-D710 is the way to go. There are other options out there, from experience this is the best.