AE6PS

Automatic Vehicle Location (AVL) is automatic tracking of a vehicles current location. AVL can also provide course, altitude, velocity, and telemetry information. In the amatuer radio world, most AVL uses APRS, a protocol developed by Bob Bruninga, WB4APR.  Position is normally acquired by a connected GPS receiver, and it is normally transmitted using AFSK on 144.39MHz. Equipment ranges anywhere from tiny embeded controllers (http://n1vg.net/opentracker/) to entire computers (http://www.loopfree.net/xlaprs/. There are even radios with APRS controllers built in.  There is a new, more flexible, and open protocol, OpenTRAC, being developed.