The main function of the acoustics subsystem is to observe an incoming acoustic signal and convert it into a digital signal to be analyzed. This system consists of an USBL (Ultra Short Baseline) sensor array and a Digital Signal Processor (DSP) board. The USBL consists of a piezoelectric quad element array, baffle, and preamplifier card. The DSP consists of a set of variable gain amplifiers, band-pass filters, ADC, and a digital signal processor (DSP).

The main function of the USBL system is to receive the transmitted acoustic signal. This system is also responsible for calculating the azimuth angle in the horizontal plane and elevation angle in the vertical plane. These angles are used to determine the position of the transmitting acoustic device. To calculate these angles incoming pressure waves are measured and translated into voltages by each array element . By comparing the voltage and the time of arrival between the two horizontal elements 1 and 2 the azimuth angle can be calculated. By comparing the voltage and the time of arrival between the two vertical elements 3 and 4 the elevation angle can be calculated.