Patent ID: 6069585
Filing Date: 2000-05-30
Classification: G01C,G01S

Abstract:
Personal direction-finding apparatus for determining a direction to be followed in order to reach a predetermined spot either in a straight line or by following a predefined path, comprising a headset (1) provided with left (2g) and right (2d) earphones for binaural monitoring of sound signals, a circuit (4) generating a track error signal (S.sub.c), representing an angular deviation (C) between a direction (X) to be followed and a direction (Y) effectively followed by a user of the apparatus, a generator of a low-frequency electric signal (5) in a spectrum of audible frequencies and a processing circuit (3) having first and second inputs, respectively connected to an output of the track error signal generating circuit (4) and to an output of the low-frequency signal generator (5), and having two outputs respectively connected to the two earphones (2g,2d), in order to produce sound signals differentiated for the left and right earphones as a function of the track error signal (S.sub.c) and to furnish a sound signal perceived by the user as seeming to come from a point located in the direction (X) to be followed, wherein the circuit (4) generating the track error signal (S.sub.c) comprises a magnetic compass (6), borne by the headset (1), outputting a first magnetic heading signal (S.sub.a) corresponding to a magnetic heading (A) of the direction (Y) effectively followed, a receiver of a position location and navigation system (7) outputting a second heading signal (S.sub.b) to be followed representing a heading of the direction (X) to be followed and a track error computing circuit (8) having a first input connected to the magnetic compass (6) and a second input connected to the receiver (7) and effecting a subtraction between the second heading signal (S.sub.b) to be followed and the first magnetic heading signal (S.sub.a) in order to deliver the track error signal (S.sub.c) as a result of the difference, the track error signal being applied to the output of the track error signal generator circuit (4).