Design and Experimental Evaluation of an Active Underwater Inflatable Co-prime Sonar Array (UICSA)

We consider underwater target detection by using a novel active, self-contained and rapidly deployable underwater inflatable co-prime sonar array (UICSA). In particular, we measure the received signal strength (RSS) and angle-of-arrival (AoA) of acoustic signals reflected by an underwater target. Measurements from different positions of the transmitter with respect to the UICSA are organized in a three mode real-valued tensor. Then, the conformity of each entry with respect to all other data points in the tensor is calculated based on recursively refined calculations of $L_{1}$-norm tensor subspaces. Conformity values are then used for the detection of an underwater target. We evaluate the data conformity of RSS and AoA recordings acquired from the testbed deployment of a seven-element UICSA prototype and three underwater acoustic transmitters at Florida Atlantic University. We show for the first time that conformity evaluation over multi-modal data measurements can accurately detect the presence of an underwater target.