An Application of Distributed Long BaseLine - Node Ranging in an Underwater Network

The basic theory of operation of Distributed Long BaseLine (DLBL), a method for measuring range between underwater assets, is presented. DLBL is conceived to work on top of existing communications infrastructures, explicitly aiming for an algorithmic, as opposed to hardware, solution for node localisation. The theoretical performance, with regards to latency, measurement update rate, error influences and induced acoustic overhead are discussed and compared with more standard LBL approaches. DLBL development and design are discussed in the context of the MORPH EC FP7 project, an underwater technologies integration endeavour that utilises distributed physical assets to accomplish survey missions in complex, full 3D environments, beyond the capabilities of the current state of the art. Preliminary experimental data, collected on a bottommounted 4- node network, is presented.