Method and apparatus for determining vehicle present location using a location determination system (LDS), such as GPS, GLONASS, Loran or an inertial navigation system, that receives LDS signals from two or more sources. An LDS signal antenna and receiver/processor, an interrogation signal (IS) receiver means and IS responder means are electrically connected and carried on the vehicle. When a vehicle trigger event occurs, a specified vehicle IS is broadcast and is received by the IS receiver means. The IS receiver means causes the LDS receiver/processor to obtain vehicle present location information and to provide such information for the IS responder means, for transmission to an IS contact receiver (selected based upon vehicle present location). The IS receiver means and IS responder means are independently selected to be a cellular phone receiver, a paging signal receiver, a WAN/LAN workstation, or an Earth-satellite-Earth radiowave link, such as ORBCOMM.SM.. Optionally, the LDS receiver/processor is kept in a "sleeper" mode, to conserve power until the IS receiver receives and responds to the specified IS, or is periodically activated to update the LDS antenna present location. Presence of the LDS equipment, IS receiver means and/or IS responder means are concealed on the vehicle. In another embodiment, a trigger event sensor is positioned on the vehicle and the responder means is caused to transmit to the vehicle present location information when a vehicle trigger event occurs, such as unauthorized movement of or entry into the vehicle, or collision of the vehicle.