Adaptive detection of range-spread targets in homo-geneous and partially homogeneous clutter plus subspace interference

Adaptive detection of range-spread targets is consi-dered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent sub-spaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homoge-neous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counter-parts,especially for mismatches in the signal steering vectors.