The typical approach to radar target classification is to image the target with waveforms that provide high resolution and low sidelobes, and then to compare the target images to a template library. In this chapter, we reconsider whether imaging-based metrics for waveform design are best for target classification, and develop alternative design strategies that result in waveforms with improved classification ability, but not necessarily a good ambiguity function by traditional notions. After presenting waveform design strategies based on optimizing signal-to-noise ratio or mutual information from a wide-sense stationary (WSS) ensemble of target impulse responses, we apply the design methods to the problem of radar target classification through a two-step process. The first step is to modify the design methodology that was based on WSS targets to account for the finite duration of practical target responses. The second step is to use the target class probabilities and impulse response library to calculate a weighted power spectral variance over target classes, which is then substituted into the design equations. The use of target class probabilities enables the waveform to be adapted in response to previous transmissions. Waveform behaviour and performance are studied over several different clutter and noise scenarios. The target impulse response library for these studies is based on finite-difference time-domain (FDTD) simulation of a publically available CAD model of an F-16 aircraft.

Inspec keywords: image classification; radar clutter; radar imaging; image resolution; probability; finite difference time-domain analysis

Other keywords: weighted power spectral variance; radar target classification; two-step process; target impulse response library; finite-difference time-domain simulation; clutter and noise scenarios; FDTD simulation; adaptive waveform design; optimizing signal-to-noise ratio; noise scenarios; target class probabilities; imaging-based metrics; F-16 aircraft; template library; WSS; wide-sense stationary; practical target response finite duration; CAD model; target images; mutual information

Subjects: Radar equipment, systems and applications; Other topics in statistics; Other numerical methods; Optical, image and video signal processing