Application of Subband Decomposition to ESPRIT Algorithm

ESPRIT algorithm is a direct DOA estimation method,of which the performance degrades greatly if the signal-to-noise ratio(SNR) is low and signals correlate with each other.A multi-resolution algorithm for DOA estimation is therefore presented,namely the subband-based ESPRIT algorithm(SB-ESPRIT),which takes advantage of the subband decomposition of fullband signals then estimates the subband DOAs via ESPRIT method.A mapping-back manipulation is used to map the estimated subband spatial frequencies onto the fullband ones.The rotational invariance of the subband signals is also proven.Simulation results showed that SB-ESPRIT will not only improve the resolution of eigenstructure-based method but also decouple the coherent signals if the subbands are properly decomposed.The root mean square error(RMSE) of SB-ESPRIT is also lower than that of ESPRIT.