A performance comparison of smoothing approaches for high-resolution active direction-finding of completely-correlated targets

For high-resolution active direction-finding of completely-correlated targets, one can use two approaches: the frequency-domain smoothing and the nonfrequency-domain smoothing such as spatial smoothing or multidimensional search of signal-subspace. The authors present a performance comparison of the two approaches for the fluctuating target cases under equal transmitted-energy constraints. Both theoretical analysis and simulations are used to study the performances of the detection (determination of number of targets) and angle estimation. It is found that frequency-domain smoothing can significantly outperform nonfrequency-domain smoothing under the equal transmitted-energy constraint