Method of and apparatus for providing information as to the existence and/or position of objects.

摘要

A method of locating an object by wave energy reflection and an apparatus therefor in which receiving outer transducers (11R, 11L or 111R, 111L) provide directional receptivities represented by polar lobes diverging on opposite sides of a reference axis (15) and an inner receiving transducer (13 or simulated from 111R, 111L) provide a directional receptivity represented by a narrower polar lobe centered on the reference axis. The signals received from the outer transducers (11R, 11L or 111R, 111L) are operated upon in channels (II, 111) of the receiver to modulate them with a frequency swept local signal derived from the transmitted signal and develop indicator signals of difference frequency between the transmitted and received frequencies and which represent the range of the object. The outer signals are displayed binaurally, to enable the user to achieve firstly approximate directional sensing by binaural effect, and thereafter more accurate directional sensing by the use of signals developed in a central channel (IV) and derived from the inner transducer (13) or outer transducers (111R, 111L) simulating an inner transducer. Gain in channels (11 and III) fed from the outer transducers is preferably adjusted as an inverse function of signal strength in the channel (IV). Higher frequency components are preferably accentuated in the inner channel to improve object character recognition.