In this paper, the use of ESPRIT is explored with relatively small baseline acoustic sensor arrays for passive direction-of-arrival (DOA) estimation and tracking of ground vehicles in the battlefield environment. Classical delay-sum beamformers do not provide high-resolution DOA estimates and their ability to resolve closely-spaced targets is limited. This deficiency is due to the geometric constraint of the sensor array; the baseline cannot be expanded beyond a few meters due to the lack of spatial coherence. ESPRIT is attractive for acoustic array processing, operating at a lower computational rate and less sensitive to sensor array imperfections than comparable high-resolution DOA algorithms. Preliminary experimental results obtained from the application of narrowband ESPRIT for a single tracked vehicle, which is a wideband acoustic source, look promising.