Abstract: A method of measuring an angle in three dimensions relative to a reference direction. In the method:a transducer array emitter is placed in a known position relative to the reference direction;the transducers of the array are excited so as to emit ultrasound waves in air mainly in a firing direction;by applying phase offsets between the excitation signals for the transducers of the array, the firing direction is varied, thereby causing it to scan a given observation zone, while simultaneously the echo received in the vicinity of the emitter is measured; andthe looked-for angle is determined from the known position of the emitter relative to the reference position, and from the firing direction at the moment when the echo amplitude is at a maximum.