High-resolution emitter direction finding using a phased array antenna

Signals from several uncorrelated emitters are received by a uniformly spaced linear phased array, and the bearing angles of the emitters are determined from output power measurements only. The output power is used to estimate the correlation matrix of the signals present at the element level. The beampointing and dwell-time agilities of a phased array are exploited, such that errors in the matrix estimate are minimized, subject to a constraint on the data collection time. A simple spectral estimation technique is described which improves on the accuracy and resolution of the maximum entropy spectrum while suppressing spurious responses. Simulations demonstrate clear resolution and good accuracy for closely spaced emitters using practical SNR's and data collection time.