We made a big step forward in the past weeks with a successful test of the GPS system that is to be used on the Mini-AUEs. The system uses the Global Star Network to transmit the location of the vehicle to a remote server. This information can then notify researchers that the vehicle has returned to the surface and give its precise location to aid in recovery.
The Global Star network has significant advantages over other networks due to much lower cost (single transmission costs are on the order of $0.15) and its widespread use. However, adapting the RF electronics to work while bobbing around at the ocean surface was a non-trival task. The positive results of this test make us optimistic that the Global Star system will provide a reliable solution to location and recovering these autonomous underwater explorers.
The figure below shows GPS fixes sent from the vehicle over the Global Star network. The upper left corner shows a view of the vehicle in the water.
For more information about the AUE project check out the Autonomous Underwater Explorer Page.