Automated Ship Routing

Abstract

The U.S. Navy's Fleet Numerical Weather Central has developed a numerical model to compute realistic time tracks for transoceanic shipping using short-range dynamic forecasts (40-72 hrs) and extended-range statistical forecasts to destination. This model resides in a computer program that is utilized by watch standers to prepare original routes and underway diversions for about 600 U.S. Navy ships a year. Global minimum time routes (GMTR) are computed twice daily for ships using optimum track ship routing (OTSR) service by this program, which considers navigation, environmental surveillance, environmental constraints, and ship performance curves. Maintenance of environmental surveillance and application of environmental constraints is accomplished through grids that represent the oceanic areas of the world and contain environmental parameters such as significant wave height and direction, frequency, fog, currents, and wind; however, any parameter or combination of parameters which can be represented numerically may be used in determining the GMTR. Comparison of the GMTR and the actual route sailed is possible by the computation of a post voyage verification route using actual environmental data. Ice areas are depicted (through the use of satellite data) and are utilized to constrain the global minimum time route selections. This is a description of the logic and the environmental parameters that produce the automated navigation, route surveillance, original route recommendations, and route verification.