Correlated Non-Coherent Radar Detection for Gamma-Fluctuating Targets in Compound Clutter

TL;DR

This paper develops a comprehensive radar detection model for gamma-fluctuating targets in compound clutter, accounting for correlations in target RCS and clutter speckle, with practical computation methods demonstrated.

Contribution

It extends existing gamma-fluctuating target models to include correlations at the voltage level, enabling more accurate detection performance analysis.

Findings

Extended the target and clutter correlation model to the voltage level.

Formulated detection using square-law non-coherent pulse integration with correlation.

Provided efficient computational methods using saddle-point approximation.

Abstract

This work studies the problem of radar detection of correlated gamma-fluctuating targets in the presence of clutter described by compound models with correlated speckle. If the correlation is not accounted for in a radar model, the required signal-to-interference ratio for a given probability of detection will be incorrect, resulting in over-estimated performance. Although more generally applicable, the is focus on airborne maritime radar systems. Hence K-distributed sea clutter is used as the main example. Detection via square-law non-coherent pulse integration is formulated in a way that accommodates arbitrary partial correlation for both target radar cross-section (RCS) and clutter speckle. The obstacle to including this degree of generality in previous work was the fact that Swerling's original characterization of the standard RCS fluctuation classes as gamma distributions for the power is not sufficient for the inclusion of both correlation sources (i.e.target and clutter speckle) for gamma-fluctuating targets. An extension of the model is required at the quadrature component (i.e. voltage) level, as phase relationships can no longer be neglected. This is addressed in the present work, which not only postulates an extended model, but also demonstrates how to efficiently compute it, with and without a number of simplifying approximation schemes within the framework of the saddle-point technique.