  OUXT-Polaris has been developing an autonomous navigation system by
participating in the Maritime RobotX Challenge 2014, 2016, and 2018. In this
paper, we describe the improvement of the previous vessel system. We also
indicate the advantage of the improved design. Moreover, we describe the
developing method under Covid-19 using simulation / miniture-size hardware and
the feature components for the next RobotX Challenge.
