DATATRAK automatic vehicle location and position reporting system
K.M. Banks · 2003
This system is designed specifically for land use, although equally efficient on boats and aircraft, particularly helicopters. Hyperbolic radio location is used with low-frequency transmitters spaced at 150 km intervals. Time division multiplexing permits up to 32 transmitters on one pair of frequencies. A one-way data system synchronized to navigation transmission, permitting the use of time slot multiplexing over 1500 vehicles reporting every minute, can be accommodated on one frequency. Base stations collect the data from vehicles and pass it to a data network for transmission to control rooms. Displays, digital maps, plotters, and VDU displays give a comprehensive display facility to users. The compact vehicle equipment consists of the LF navigation receivers, a powerful microprocessor board, the UHF transmitter and a stabilized power supply. The unit measures 67 mm*207 mm*265 mm and has a power consumption of 40 W. An active antenna is diplexed to receive LF and transmit UHF. Applications to high value load carriers, general freight operators, emergency services and public transport are considered.>