A method to locate reflectors, based on the spectral analysis of ultrasonic received echoes, is provided in this study. The main contribution of this work lies in the spectral analysis for bearing estimation. A single ultrasonic transducer, acting as emitter and receiver, is used. The transmitted signal is a 1023-bits Kasami code BPSK modulated by a carrier that ranges from 30 kHz to 55 kHz, implying a 6-component transmitted pulse. Since the ultrasonic transducer works as an angle-dependent filter, it is possible to estimate the bearing angle of the reflector based on the received spectrum. It is shown how the amplitude of each frequency contains information about the environment, particularly about the bearing angle of the reflector. Finally, a set of experimental results is included to validate the sensory system, showing how it can deal with realistic reflectors.