Abstract: The location of a vehicle having an assigned serial number is determined at a location remote from the vehicle with a system including a central master station and plural local networks, each having a local master station in a bi-directional communication link with the central master station. Each vehicle includes a receiver for Loran-C emissions, a transmitter for modulating a first carrier having a frequency much higher than the Loran-C emissions with pulses having time positions corresponding with and synchronized with Loran-C pulses as the received Loran-C emissions, and a receiver for a second carrier having a frequency much higher than the Loran-C emissions. The first carrier is modulated by vehicle serial number signals. The carriers are transmitted via radio links between the local master station and vehicle. The local master station responds to the first carrier to detect the time difference between pulses modulating the first carrier to determine vehicle position.