Research
Evaluation of acoustic Doppler diver navigation console
HENCH, J. L., and J. H. ROSMAN, in review. Analysis of bottom-track and compass error in a self-contained acoustic Doppler diver navigation console. Submitted to Journal of Atmospheric and Oceanic Technology.
Abstract
The Cobra-Tac (Teledyne RD Instruments) is a self-contained diver navigation system based on acoustic Doppler velocity log (DVL) technology that uses dead-reckoning to compute displacements from a known starting point. The navigational accuracy of the system was evaluated using a series of field tests with known solutions. There was an obvious directional bias in the navigation measurements, with positional errors as large as 5% of the track length. An analysis of this error showed that the DVL speed measurements were extremely accurate and that most of the position error could be explained by heading dependent compass error. A post-processing correction procedure was derived that significantly improves Cobra-Tac position estimates. After correction, position errors in the field tests were well within specifications.
Photograph of scuba diver navigating with a Cobra-Tac over a coral patch reef.