A novel method of DOA estimation on sparse uniform circular array

We propose a beamspace transform method to estimate direction-of-arrival(DOA) of coherent signals on sparse uniform circular array(UCA). By incorporating necessary phase modes into the beamspace steering vector and introducing a phase shift matrix before weight vectors, a conjugate symmetric beamspace steering vector is rebuilt based on phase mode excitation, therefore spatial smoothing can be applied to deal with coherent signals and root-MUSIC is also available to decrease computational load. What's more, spatial smoothing also improves the performance of resolution under condition of low SNR(signal to noise ratio) or fewer snapshots because it doubles the data amount. These performance merits are verified by computer simulations.