Navigation and locating device e.g. for lost children

摘要

The device includes a satellite navigation system (18). A person (22) carries a passive unit (20) which is activated by a coded radio signal from a transmitter (14). When the unit is activated a signal is transmitted received from the satellite navigation system which gives the terrestrial coordinates of the location of the person. The signal is decoded at a control centre (10). Preferably, the radio signal is in the long wave range. The coded radio signal is received via a network of very short wave transmitters, such as a radio telephone network.