Collinearity problems in passive target localization using direction finding sensors

In passive target localization using direction finding (DF), there are particular sensor-target placements that cause large biases in the estimates or the failure of estimates to converge to a unique solution. Identification of such problematic configurations is crucial for implementing estimation and tracking algorithms effectively. In this paper we propose four methods for characterizing near-collinearity problems in a sensor-target configuration which enable one to quickly and easily identify cases in which DF-based localization will fail to obtain a solution or give unreliable results.