Acoustic Communication and Navigation for Gliders and Drifters in the Marginal Ice Zone

Lee Freitag
Woods Hole Oceanographic Institution
Seminar Date: 
21. January 2013 - 11:15 - 12:00
Lecture room, Ground Floor, NERSC

Abstract – Navigation of gliders operating under Arctic ice is important for geo-referencing subsea data with that collected by above-ice sensors. However, bottom-mounted navigation beacons cannot be used to support ice-based experiments because the sensors field will move with the natural drift of the ice. Navigation signals transmitted by sources suspended from the ice solves the movement problem, but creates another: the sources must broadcast their locations so that a real-time position can be calculated by the receivers. While drifters do not need real-time position because they cannot steer, gliders that need to stay in the vicinity of the sensor field must receive source locations along with travel time measurements, requiring data communication plus the navigation signals.

Experiments in under-ice acoustic communication and navigation to support 50-100 km ranges were undertaken in 2010 in the Fram Strait on the K/V Svalbard in collaboration with NERSC, and in 2011 north of Alaska during US Navy exercises. These experiments demonstrated the feasibility of transmitting data to support mobile sources. In this talk the results from those experiments will be presented and the status of a new Office of Naval Research MIZ project involving gliders that will navigate under ice in real-time will be reviewed. The ONR MIZ program will start trials in 2013, with a major field experiment in 2014 in the Canada Basin.