Design and performance measurement of a digital embedded system implementing a I/Q demodulator for AoA range-based localization in underwater environment

Many embedded systems have been developed for terrestrial sensor localization, however, they are not applied directly to underwater sensor localization because of attenuation of GPS and RF signals underwater, making localization underwater particularly challenging. This paper presents the design, implementation and performance measurement of a digital embedded system, able to localize sensors underwater by measuring the angle of arrival of acoustic signals detected by means of a small array antenna that combines three matched hydrophones. A digital In-phase and Quadrature (I/Q) demodulator, implemented in a Digital Signal Processor (DSP) is proposed to measure the angle of arrival of pure tone narrow band acoustic signals sent by acoustic transmitters and received at the hydrophone array of acoustic receivers. Simulations and sea trials have been conducted successfully to evaluate the performances of the realized system.