autonomous underwater gliders
... that the US Navy has been developing autonomous underwater gliders to track submarines and marine mammals?
... that the US Navy has been developing <b id="mwDy4"><a href="./Liberdade_class_underwater_glider" id="mwDy8" rel="mw:WikiLink" title="Liberdade class underwater glider">autonomous underwater gliders</a></b> <i id="mwDzA">(example pictured)</i> to track submarines and marine mammals?