A random-signal approach to robust radar detection

Abstract

Abstract-The paper presents a novel family of robust radar receivers for the problem of detecting the possible presence of a coherent return from a given cell under test. The idea is to introduce a random signal in addition to the nominal steering vector, with a given structure, but whose entity is estimated from the data (hence can also be zero). While in the classical formulation the target signature is present only in the mean of the likelihood function, and recent work investigated tests based on the sole covariance matrix, the proposed approach splits the target signature between mean and covariance. In particular, the complex amplitude is modeled as an unknown deterministic parameter while the random part of the signature is included in the covariance to promote robustness. Preliminary results for different choices of the design matrix (that is, of the structure of the covariance matrix of the random signal) show that a palette of behaviors can be obtained, with different trade-offs between loss under matched conditions and robustness to mismatches.

Design of Robust Radar Detectors Through Random Perturbation of the Target Signature

“…A third parametric detector is obtained by an ad-hoc generalization of one of such GLRTs. Twostep GLRT-based detectors have been presented in our preliminary work [24]. The detectors derived here have different complexity and behavior.…”

“…For a fair comparison, only values that ensure practically the same performance of Kelly's detector under matched conditions are considered, in particular β = 0.5 and β = 0.8 for Kalson's detector and γ = 0.45 and γ = 0.4 for the KWA. For reference, the AMF [5], is also reported in all figures, because it is a well-known robust detector; however, 4 For completeness, we mention that [24] provides the general derivation (for any Σ) and a closed-form for Σ = C following the two-step GLRT approach, namely deriving the GLRT for known C and then using as replacement an estimate Ĉ (from secondary data); such detectors are however less powerful than one-step GLRTs. In Appendix C we show that for Σ = vv † the two-step GLRT is equivalent to the AMF, whereas the proposed one-step GLRT for the same choice of Σ is equivalent to Kelly's detector (ref.…”

A novel approach to robust radar detection of range-spread targets

“…More recently, a framework to design robust decision schemes for pointlike targets has been proposed [18,19]. The idea is to add to the H 1 hypothesis a random component that makes it more plausible, hence hopefully the detector more robust to mismatches on the nominal steering vector v.…”

“…Motivated by the above results, we investigate the potential of this approach for robust detection of range-spread targets, i.e., we extend the modeling idea in [18,19] to the case of a target occupying more than one cell in range. In particular, we derive a robust GLRT-based detector for rangespread targets and also propose an ad hoc parametric receiver to obtain additional flexibility in the level of robustness.…”