Sonar System Combining an Emitter Array With a Sparse Receiver Array for Air-Coupled Applications

In this paper, we describe the application of an emitter array based on simultaneous transmit-synthetic aperture beamforming (ST-STAB) to improve the signal-to-noise ratio in an existing, 3-D, air-coupled sonar system. The ST-STAB approach allows for the simultaneous emission of orthogonal codes by an array of emitters, which are decoded in the receiver stage, eliminating the need for multiple measurement cycles. By adding more emitters to the sensor system, the overall emitted acoustic energy is increased, while the ST-STAB approach ensures an efficient use of measurement time. We elaborate on the mathematical model of the sensor and signal processing system, provide the associated point spread functions and show experimental validation the constructed prototype array.