Inertial Sidescan Sonar: Expanding Side Scan Sonar Processing by Leveraging Inertial Navigation Systems

Synthetic aperture sonar (SAS) is emerging in the survey industry, but traditional side-scan sonar (SSS) remains the standard. Synthetic Aperture Mapping Sonar (SAMS) aims to combine the user-friendliness of SSS with the advanced capabilities of SAS, providing consistent resolution and improved area coverage. It combines a synthetic aperture sonar hardware with an inertial navigation system (INS), crucial for autonomous underwater vehicles and towfish platforms navigation. Precise INS measurements and acoustic data redundancy ensure accurate motion compensation for SAS processing. However, platform displacement and maximum range-to-altitude ratios must be managed to maintain SAS image quality, which imposes harsh operating conditions during survey operations, notably platform motion stabilization and maximum operating speed. Inertial sidescan sonar imaging allows greater flexibility in platform speed by averaging signal magnitudes instead of summing them in phase. This method enhances contrast and increases area coverage rates with a range-increasing resolution similar to SSS.