Tunnel searcher location and communication equipment

摘要

A method of locating and plotting tunnels by moving a portable receiving unit in which is an orientatable coil over an area to be searched while locating a transmitting unit in the tunnel itself, transmitting a signal from the transmitting unit which has a short pulse duration but a considerably longer interval between pulses, and measuring the distance between the transmitter and receiver by amplitude calculation, means being provided also to measure the relative angle of the receiver in relation to the transmitter by orientating the coil to permit depth and position calculation to be determined.