Spatially coded signal model for active arrays

This paper addresses the problem of target detection and localization by radar or active sonar systems. A novel configuration, in which the transmitted signals are spatially coded, is proposed. The main advantages of this new configuration are: avoiding beam-shape loss, having a larger virtual array aperture and therefore narrower beams, increasing the angular resolution, and having the ability to detect and localize a greater number of targets. This configuration enables array processing in the transmit mode in addition to the receive mode. The generalized likelihood ratio test (GLRT) and the maximum-likelihood (ML) estimator are derived for target detection and localization according to the new model configuration. The performance of the array processing algorithms for this problem is studied theoretically and via simulations.