73090138
Jun 11, 1976
Dec 27, 1977
ELECTRONIC ACOUSTIC NAVIGATION SYSTEMS-NAMELY, TRANSPONDERS, INTERROGATOR TRANSDUCERS, INTERROGATOR/RECEIVERS, PROCESSORS, PLOTTERS AND KEYBOARD/PRINTERS FOR USE IN DEEP WATER SURVEYS, RIG MOVES, PIPE LAYING, AND NAVIGATION OF SUBMERSIBLES
Electrical and Scientific Apparatus