MIMO sonar systems for harbour surveillance

Multiple Input Multiple Output sonar systems offer new perspectives for target detection and area surveillance. This paper introduces MIMO sonar systems and focuses on its capabilities. The multiplication of the number of transmitters and receivers not only provides a greater variety in terms of target view angles but provides also in meaningful statistics on the target itself. Assuming that views are independent and the MIMO system is large enough we demonstrate that target recognition is possible with only one view from the full system. We also demonstrate that such systems solve the speckle target noise and decorrelate individual scatterers within one cell resolution. We show that MIMO systems can achieve super-resolution images and surpass the resolution given by equivalent SAS (Synthetic Aperture Sonar) systems. To demonstrate those capabilities we develop a physic based MIMO simulator capable of modelling cluttered and very shallow marine environment similar of harbour environment. Thanks to the simulator and taking advantage of the degree of freedom that MIMO systems offers, we also present autofocus algorithms that automatically estimates mid-water target parameters such as speed, orientation or depth.