A survey on two-stage decision schemes for point-like targets in Gaussian interference

In recent years, the design of so-called tunable detectors has raised significant interest in the radar community. The class of tunable detectors has been shown to be an effective means to attack detection of mainlobe targets or rejection of coherent repeater interferers in the presence of clutter and/or possible noise-like in-terferers. Tunable detectors allow adjustment of the rate at which the probability of detection Pd decreases as the received signal departs from the nominal one. In this case, a mismatch between the nominal and the actual steering vector is present. We refer to the capability of rejecting or detecting signals as directivity. Existing architectures can be classified according to their directivity as follows [1]: ▸ Robust decision schemes provide good detection performance in the presence of echoes containing signal components not aligned with the nominal (transmitted) signal (as shown in Figure 1, where target returns lie on a direction that is not aligned with the antenna beam boresight). ▸ Selective decision schemes are capable of rejecting signals whose signature is unlikely to correspond to the signal of interest to avoid false alarms.