A Preliminary Design Study of a Re-Deployable Underwater Test Bed
Dr. Nagi Khadr | Parsons Government Services, Inc.
This preliminary study focused on test beds capable of providing reliable platforms for model validation, in situ demonstrations, and performance intercomparisons. This study explored the use of special re-deployable materials that ensures a consistent predefined, yet flexible, item emplacement process.
The approach to the preliminary design consisted of: (1) conducting an analysis to determine item distribution scenarios that will apply to all sensor modalities and systems of interest over a variety of conditions; (2) fully elaborating on and investigating the feasibility of implementing a redeployable item emplacement process that can be used for a range of different test bed scenarios. The main conceptual idea relies on deploying re-useable materials that are lightweight, can be set up on the water surface, submerged, and then outfitted with an adaptable mesh fabric containing a known spatial distribution of uniquely identifiable acoustic pinger tags; and (3) researching site possibilities for installing test beds that will apply to the largest possible variety of conditions to all sensor modalities and systems of interest.
Underwater standardized test sites with scenarios similar to the calibration lanes, blind grid, and open area found on the terrestrial Standardized Test Sites at Aberdeen Proving Ground (APG) and Yuma Proving Ground (YPG) are what is envisioned for an underwater test site. The basic concept of the re-deployable underwater test bed consisted of a lightweight grid framework that can be efficiently assembled on the water surface before being submerged and guided to the bottom. This grid unit of four six m X six m (6X6) cells can either be a standalone structure or add to an existing grid network. The goal would be to deploy the grid unit from a small boat or skiff in one trip with two people. The redeployable underwater test bed platform will be placed on the water bottom and can accommodate pingers with known unique identifications (ID) at regular intervals in two dimensions. The pingers identify potential locations for which to emplace prescribed items in a given configuration either proud on the surface or buried at a given depth. The pingers allow divers armed with underwater receivers to efficiently navigate from one desired item emplacement location to the next based on a pre-planned and thought-out seeding strategy. After a rigorous ranking process, five potential sites were identified based on identifying the following: current land ownership and existing local/on-site infrastructure; the availability of boat ramps and/or marinas in the vicinity; and the proximity of each identified boat ramp/marina to each of the depth column areas.
This preliminary study is one of several undertaken in an attempt to clarify the best course of action to take when designing an underwater test site. If the proposed re-deployable item emplacement process is shown to be both feasible and cost-effective, this will pave the way towards establishing an underwater test site with test beds that are more complex than just simple grids and would rival the success that the terrestrial Standardized Unexploded Ordnance (UXO) Technology Demonstration Sites have had in evaluating and comparing emerging and existing technologies. Other benefits come from steps (1) and (3) of the technical approach in determining item distribution scenarios, and a ranked list of MR sites that could potentially host the desired test bed scenarios.