Adaptive detectors for MIMO radar with sidelobe signal rejection capabilities

Antenna beam patterns in MIMO radar systems (as in any radar system) exhibit sidelobes. Naturally it is possible for clutter and other undesirable signals to be detected accidently through these sidelobes. In a MIMO radar system this has the effect of misaligning the mainbeam steering vector and consequently reducing detection performance. In this paper we develop and examine two adaptive processing schemes aimed at reducing unwanted signals entering the system through sidelobes and hence restoring the steering vector to its true position. In this way signal to noise and detection performance are also largely restored. The MIMO version of an adaptive beamformer orthogonal rejection test (MIMO-ABORT) method together an adaptive detector with conic rejection (MIMO-ACR) are developed, that exploit the generalized likelihood ratio principle. Subsequently the constant false alarm rate (CFAR) properties of the two proposed detectors are demonstrated. The performance of the MIMO-ABORT and the MIMO-ACR detectors are numerically evaluated. The results show that the two detectors can reject sidelobe signals with good performance at the cost of a slight reduction in mainlobe signal detection performance, as compared with MIMO version of Kelly´s GLRT (MIMO-GLRT).