A Comparison of Smoothing Approaches for Angle Measurement

For high-resolution active direction finding of completely correlated targets, one can use two approaches, Le., the frequency-domain smoothing [1] and the non-frequency-domain smoothing such as various spatial smoothing [2–7], or multidimensional search of signal-subspace [8, 9]. A performance comparison of the two approaches for the fluctuating target cases under equal transmitted-energy constraint is presented. Both theoretical analysis and simulations are used to study the performance of the detection (determination of number of targets) and angle estimation. It is found that the frequency-domain smoothing can significantly outperform the non-frequency-domain smoothing under the equal transmitted-energy constraint.