Investigation of array robustness to sensor failure

The presence of uncertainties in the array response, due to sensors operational malfunctions and environmental effects, results in a performance degradation often greater than the application requirements can afford. Various attempts have been made to measure the effect of the presence of uncertainties on the performance of direction-finding (DF) algorithms and, moreover, several methods have been developed to either detect or partly rectify the resulting defects in performance and hence improve the robustness of the array system. However, the impact of sensor response uncertainties on the ultimate array DF capabilities, as they are determined by the array manifold characteristics, has not been considered thoroughly. In this paper, the sensitivity of array DF capabilities to sensor response errors is first formulated and investigated. Robustness and reliability measures are then proposed. Such measures can be used as tools for the evaluation of each sensor's importance within the array geometry and as criteria for the comparison of a number of array geometries.