Electronic homing system

Claim 1

A homing system for directing the user to one of a plurality of locations comprising: a plurality of remote signal processing modules for being placed at stationary locations to which the user may desire to be led comprising means for transmitting an uncoded omnidirectional sonic response signal, means for receiving a coded request signal, and means for decoding said request signal, said remote modules each responding to a unique coded request signal, and a mobile module comprising means for repetitively at spaced intervals transmitting coded omnidirectional EMR request signals, means for selecting a remote module by selecting the code for the omnidirectional request signals, a plurality of distinct means spaced apart and fixed to said mobile module for receiving a sonic response signal from a selected one of the plurality of remote modules initiated by each of said spaced request signals, means for generating an internal representation of the distance between the receiving means and the selected module from the time measured between the transmission of the request signal and the receipt of the response signal, means for comparing subsequent representations of the distances, means for generating an internal representation of the direction to the source of the response signal based upon the difference in the time of arrival of the response signal at said distinct means for receiving, output means indicating to the user whether the distance is increasing or decreasing continuously as the mobile module is moved and the direction to the source of the response signal, and an input means for selecting one of said remote modules based upon the unique request signal to which it responds.