Experimental demonstration of the angular resolution enhancement of a monostatic MIMO sonar

In this contribution we show by experimental tests the improvement of the angular resolution of an active monostatic Sonar system when using the Multiple-Input-Multiple-Output (MIMO) principle. This principle allows the design of a high-resolution sonar with a lower number of transducers required compared to a conventional Sonar, thus allowing the costs of the Sonar to be significantly reduced. For this purpose, a MIMO Sonar demonstrator was built and experiments were performed in a harbor basin. It is shown that the travel time information can be extended in a manner that allows a factoring of the angular resolution of the system by the number of transmitters. The key to this principle is that the respective transmission pulses of the transmitter modules can be separated from each other during signal processing on the receiver side. This can be achieved through different techniques. In this paper novel transmitter signals are presented, which are coded in a way that they can be transmitted in the same frequency and time window and afterwards be sufficiently separated by correlation filters. To evaluate and model the experiment, also a simulation was developed, which uses a simplified model of the acoustic channel to generate the received signals.