EMERGENCY ALARM METHOD AND SYSTEM UTILIZING CROSS CUEING AND RANGING TECHNIQUES

An alarm signalling method and system utilizing cross cueing between radio, audio and visible alarm signals which are emitted by an alarm signalling unit. A method and system for measuring the range between the alarm signalling unit and a receiver carried by a rescuer wherein the differences in the time of receipt at the receiver of simultaneously emitted radio and audio signals is used as a measure of range.