Development of quantitative echo sounding and high sensitive camera systems
                                  for underwater robots

      Yoichi Miyanohana, Kouichi Sawada, Yoshimi Takao, Hideyuki Takahashi,
      Ken'ichi Oda, Akihiko Matsuda, Katsuo Hasegawa and Yasuyuki Yamakoshi

    National Research Institute of fisheries Engineering Fisheries Agency of Japan
                     Ebidai Hasaki, Kashima Ibaraki 314-04, Japan

     A  four-year  project  funded by  Agriculture,  Forest  and  Fisheries  Research 
Council of  Japan has  been carried  out since  1996.  One  of the  final goals  is an 
instrumented package  of quantitative  echo sounder and  TV camera for  underwater 
robots, which are expected to be developed in the near future.  The underwater robot 
equipped with these sensing systems is one of the most effective solutions of several 
problems in hydroacoustic surveys, for  example the difficulty to identify fish species, 
the errors  caused by ship  motions, air bubbles  and propeller noise  for sailing, and 
dead zones for hull-mounted transducer.
     In the  first fiscal year (1996),  a multi-beam transducer  was developed, whose 
frequency and diameter  are 70 kHz and 118  mm, respectively.  This transducer has 
dual-beam and  split-beam capability as  well as echo-integration  within 100 meters 
depth.   A  high sensitive  stereo TV  camera system  with HARP  target was  also 
developed.   In  the second  year  (1997), the  transmitter and  the  receiver of  echo 
sounding system will  be developed, and the  performance of camera system installed 
in the diving test bed will be examined in the experimental tank.