AFRODiTE: A FluoRescence lidar simulator for underwater object detection applications

A FluoRescence lidar simulator for underwater Object DeTEction applications (AFRODiTE) is proposed to generate inelastic backscattering signals returned from a water column both in the presence and in the absence of an underwater object. The simulator models the interaction of the transmitted laser pulse with the water medium, an underwater object, and the bottom. Specifically, AFRODiTE enables simulation of fluorescence backscattering signals for a variety of light detection and ranging (lidar) system characteristics, acquisition geometries, and water environmental conditions. With respect to models for the elastic backscattering lidar signals developed in the literature, AFRODiTE may be used to test and improve not only underwater object detection methodologies based on time-resolved lidar waveform analysis but also object recognition methodologies based on spectral analysis of the object fluorescence spectral signature. Experimental comparison with real signals measured by an advanced prototypal fluorescence lidar in a laboratory artificial water column shows that AFRODiTE is effective at reproducing the inelastic backscattering signals received by a lidar system from an underwater object. Furthermore, simulations of the received signals obtained reproducing immersion of objects in the waters of the Gulf of Mexico and the North Atlantic Ocean highlight AFRODiTE potential and flexibility for generating fluorescence lidar signals acquired in different operational scenarios on the basis of various system parameters, acquisition geometries, and water environments.