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Talk-19: Change Detection for Autonomous Underwater Vehicle Simultaneous Localization and Mapping

Timothy Pohajdak, Mae Seto, Defense Research and Development Canada (DRDC).

Autonomous underwater vehicles (AUV) are platforms for side scan sonar surveys with underwater mine detection, identification, and classification as a particular example. Generally, AUVs use inertial measurements for input to their motion model and state. However, this method results in the AUV localization error increasing unbounded with time. This is mitigated, to some extent, by the AUV surfacing for a GPS fix or through acoustic communications with a surface vessel that knows its GPS location. This limits the AUV stealth and/or makes it dependent on another asset. Features from side scan sonar survey imagery can be used for AUV localization with a potential improvement over inertial methods ~V this is simultaneous localization and mapping (SLAM). The application described searches for sea bed features, in particular mine-like objects (MLO). The SLAM algorithm implemented is MIT's Incremental Smoothing and Mapping (iSAM). The MLOs are detected and identified through the analysis of images using on-board automated target recognition tools. MOOS-IvP is the autonomy framework for the OceanServer IVER2 AUVs used in the work described. In the interval between surveys, the sea bed changes due to the dynamic action of tides, currents, and human activity. Change detection is applied to identify new MLOs against the backdrop of changes to the environment and while retaining knowledge of old MLOs as localization aides. The novelty in the research is the change detection techniques given a complex and evolving environment. Simulations have been performed on an IVER2 AUV vehicle simulator with a MOOS-enabled payload computer applied to a sonar change detection dataset and the results are encouraging. In-water trials are scheduled for September 2013.

Categories:

  • Autonomous Underwater Vehicles (AUVs)
  • SLAM
  • iSAM
  • Ocean Server, Iver2 AUVs
  • Mine Countermeasures (MCM)