Arrays of Lagrangian Floats for Areal Coverage (ALFAC)
Abstract
The goal of the Arrays of Lagrangian Floats for Areal Coverage (ALFAC) project is to demonstrate operationally useful spatial coverage of a defined ocean region of interest for one year. Coverage is provided by a large array (N) of autonomous Lagrangian and semi-Lagrangian platforms that profile vertically, called floats and gloats. This approach is based on four cornerstones: (1) platforms with long lifetimes, (2) platforms with low unit cost, (3) platforms that can exploit ocean kinetic energy fields for mobility, and (4) an expert control system to leverage the large N network effect. Cornerstones (1) and (2) will be met by working closely with industry to maximize onboard power efficiency and retain low unit cost through economies of scale and advanced manufacturing. Cornerstone (3) is met by floats adjusting their depth to take advantage of stratified ocean currents. Cornerstone (4) is fundamentally a navigation and prediction challenge that exploits the trajectories of free-floating platforms in a complex ocean environment. This navigation and control system, a customized expert system, is essential for a large N approach and will be developed and demonstratedin this project.Tasks include (1) constructing the architecture of the expert system, including its ability to ingest float data and data from other sources, produce trajectory forecasts with uncertainty, and synthesize all inputs into likely-end-point maps for decision making; (2) identifying a specific region of interest, characterizing the principal oceanographic features, and determining performance metrics for the deployment of a 100 float array; (3) simulating the deployment and control of the float array in the selected region of interest; (4) evaluating the utility and cost trade-offs of incorporating EM-Apex and GLOAT floats into the array; (5) calculating predicted float reseeding requirements over time based on predicted endurance of floats and nominal failure rates; (7) assessing and prioritizing various payload options; and (8) acquiring and deploying a 100 float array in an area of interest, controlling this array for at least one year and documenting the performance in meeting the defined objectives.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2021
- Source ID
- N000142112434
Entities
People
- Thomas Curtin
Organizations
- Office of Naval Research
- United States Navy
- University of Washington