Radar Signature Prediction of Ships on a Rough Sea Surface with AURORA
Abstract
The objective of this ONR proposal is to develop an accurate description of ship signatures for understanding the battlespace performance of a variety of warships and radar systems. The PIs expect to determine the effect of rough sea surface on such radar signatures to develop a robust physicsbased model for realistic 3D ships moving on a timeevolving sea surface. The PIs will create a ship/sea surface interaction model compatible with modern ship radar crosssection (RCS) prediction software, particularly the AURORA highfrequency simulation method under development as part of the DoDs CREATERFinitiative. Specifically, because highfrequency asymptotic methods based on ray and physical optics theory (i.e. AURORA) are used to creating ship signature predictions in a reasonable amount of time, we will rayoptically characterize the sea surface effect on such signatures. Such methods, naturally, requireda rayoptical characterization of the illuminating electromagnetic (EM) field.In this five year project, we will provide guidance (YEAR 1) into the ONR/NSWCled team based on upon the deep expertise of the OSU investigators to extend AURORA capabilities and results through a written report describing the basic mathematical and computer models, the statistical RCS definition for a ship ona random sea surface, and steps towards implementation. We will then use the decoupled plane wave expansion (DePLEx) approach (YEAR 2) for computing the radar signature of a stationary ship on a random rough sea surface via examples of how sea surface randomness affects the statistical characterization of the ship RCS. We will compute the RCS with AURORA with the plane waves from DePLEx as excitation for comparison with fullscale Monte Carlo simulations. We will then compute the statistical RCS of a moving ship on a timeevolving random sea surface (YEAR 3) considering the ships center of gravity and moments of inertia in a hydrodynamics model of the ship floating on the timeevolving sea. We will then incorporate this DePLEx/AURORA into our statistical RCS model.We will modify the DePLEx/AURORA package (YEAR 4) to characterize the RCS of a ship illuminated by fields propagating through a nonstandard atmosphere such as a refractive duct. We will also use a parabolic wave equation code such as VTRPE or APM to generate the incident fields in ducting environments and transform into plane waves for the DePLEx/AURORA RCS computation. We expect to thus develop a more efficient and robust approach to obviate the intractably large number of plane waves within the conventional plane wave expansion of the EM fields incident on a ship.Finally, we will create (YEAR 5) realistic applications and validation cases to predict ship signatures within the DePLEx/AURORA framework. We are particularly interested in investigating the sea surface and environmental refractivity effects on RangeDoppler, SAR, and inverse SAR images by generating broadband RCS data over a range of aspect angles. We will also increase the robust nature and accuracy of our novel DePLEx/AURORA algorithms for ship design/system simulations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- N000142012810
Entities
People
- Joel T. Johnson
Organizations
- Office of Naval Research
- Ohio State University
- United States Navy