Bounds for aircraft tracking using a hydrophone array with unknown source frequency

The paper derives Cramer-Rao lower bounds (CRLBs) for airborne acoustic source tracking estimates using an array of hydrophones. The paper considers both bearing and Doppler frequency measurements in a two layer (air-sea) acoustic environment with unknown source frequency. Comparison of the CRLBs for known/unknown source frequencies is given; the CRLB for the known source frequency is lower than that for an unknown source frequency. The extended Kalman filter has been simulated and the results verified the new CRLB.