Double‐hierarchy heterogeneous structural detection of a subspace signal for distributed multiple‐input multiple‐output radar

Abstract The authors consider the problem of adaptive target detection in the background of interference and heterogeneous disturbance, for a multiple‐input multiple‐output (MIMO) radar system equipped with widely separated distributed antennas. The signal of interest and the interference lie in two corresponding subspaces that are mutually linearly independent. Therein, both the coordinates of two subspaces are unknown. For MIMO radar system, the disturbances of transmit‐receive pairs are heterogeneous, namely, each transmit‐receive pair has different statistics. And the disturbance in one transmit‐receive pair is non‐homogeneous. Therefore a double‐hierarchy heterogeneous disturbance is proposed. By resorting to a two‐step procedure, a double‐hierarchy heterogeneous structural detector (MIMO‐GLRTdh) is proposed in accordance with generalised likelihood ratio test for distributed MIMO radar to suppress interference and disturbance. In real scenarios, the certain structure property, existing in the covariance matrix of disturbance, such as the structural persymmetry or Toeplitz property, may be useful. Furthermore, the authors incorporate the structural persymmetry or Toeplitz property to design two structural detectors (PerMIMO‐GLRTdh and ToeMIMO‐GLRTdh), and study the impact of structure on detectors. Simulation results show that the presented detectors can acquire better detection performance and strong anti‐interference ability. In addition, the results indicate that the detection performance of distributed MIMO radar can be improved by the structure in training‐limited situations.