DDR

Abstract

DDR classifies targets by material composition. Shape and motion are not factors.

The Physics

When a pulsed SWIR laser illuminates a surface, the return signal depolarizes at a rate that depends on material structure. Water and other symmetric volume scatterers depolarize nearly equally across horizontal and vertical polarization states. Biological tissue, synthetic composites, and manufactured materials produce measurable asymmetry. That asymmetry is the Differential Depolarization Response. It is a physically grounded material signature, stable across target geometries and viewing angles.

Applications

Three operational environments suit DDR’s discrimination capability. In drone detection, drone hull composites and bird feathers produce distinct DDR signatures against a near-zero atmospheric background, enabling classification at ranges where shape-based methods fail. In radar augmentation, DDR integrates with existing radar track output as a secondary classification layer, returning a material confidence score on each cued contact without modifying radar hardware or operator workflow. In maritime search and rescue, persons in water and survival equipment produce elevated DDR signatures against an ocean surface background, enabling automated flagging of high-priority search contacts.

IP Status

A utility patent application is pending. Two provisional applications are on file (February 2026). The underlying measurement architecture covers pulsed SWIR dual-polarization detection, shared-aperture target acquisition, and multi-node tracking network embodiments.