Imaging Performance of BOSS Using SAS Processing

Synthetic data sets containing point targets and uniformly distributed point scatterers are processed to quantify the performance of BOSS (buried object scanning sonar) as a function of the lengths of synthetic and physical hydrophone apertures and the spatial interval between transmission events. The modeling shows that transmitting at half wavelength along track intervals provides near optimal performance. Increasing the number of the hydrophone lines in the rectangular receiving aperture allows transmissions at larger intervals without significant degradation of target SNR. Image resolution is modeled by measuring the width of a point target along 3 axes as a point target is moved in range and bearing. The modeling shows that the along track target resolution is dependent on the length of the synthetic aperture and center frequency for targets abeam of the sonar, and is dependent on the temporal resolution of the sonar for targets ahead or behind the sonar vehicle. Temporal resolution, which is the inverse of the pulse bandwidth, determines the vertical resolution of targets under the sonar vehicle and the across track horizontal resolution of targets off the beam of the sonar vehicle