  In this paper, we address the problem of target detection in the presence of
coherent (or fully correlated) signals, which can be due to multipath
propagation effects or electronic attacks by smart jammers. To this end, we
formulate the problem at hand as a multiple-hypothesis test that, besides the
conventional radar alternative hypothesis, contains additional hypotheses
accounting for the presence of an unknown number of interfering signals. In
this context and leveraging the classification capabilities of the Model Order
Selection rules, we devise penalized likelihood-ratio-based detection
architectures that can establish, as a byproduct, which hypothesis is in force.
Moreover, we propose a suboptimum procedure to estimate the angles of arrival
of multiple coherent signals ensuring (at least for the considered parameters)
almost the same performance as the exhaustive search. Finally, the performance
assessment, conducted over simulated data and in comparison with conventional
radar detectors, highlights that the proposed architectures can provide
satisfactory performance in terms of probability of detection and correct
classification.
