Distributed target detection in subspace interference plus Gaussian noise

• We handle the problems of detecting distributed targets in subspace interference plus Gaussian noise with known and unknown power levels.
• Two detectors are developed.
• Close-form expressions for the probabilities of false alarm and detection of the two detectors are derived.

In this paper, the problem of detecting distributed targets in the presence of subspace interference and Gaussian noise is addressed. The subspace interference signals are modeled as linear combinations of the linearly independent columns of a known subspace matrix. Two kinds of distributed matched subspace detectors are derived to handle this detection problem. The first kind of distributed matched subspace detector referred to as I-DMSD is obtained on the assumption of known noise power level. The other one referred to as II-DMSD is developed on the basis of unknown noise power level. Expressions for the probabilities of false alarm and detection of the I-DMSD and II-DMSD for unfluctuating and fluctuating target models are derived, which are confirmed with Monte Carlo simulations. Numerical simulations are conducted to illustrate the detection performance of the two detectors. It is demonstrated that both detectors ensure a constant false alarm rate (CFAR) property against the interference, and the II-DMSD also exhibits the CFAR property with respect to the noise power level.