A new covariance matrix estimation method for resolution enhancement via virtual expansion

We propose a resolution enhancement method for estimating direction-of-arrival (DOA) of narrowband incoherent signals incident on a general array. The resolution of DOA algorithm is dependent on the aperture size of the antenna array. But it is very impractical to increase the physical size of antenna array in a real environment. Therefore we propose the method that increases the aperture size by virtually expanding the sensor spacing of the original antenna array and then constructing the steering matrix of the virtual array using the proper transformation matrix. Superior resolution capabilities achieved with this method are shown by simulation results in comparison with the standard MUSIC for incoherent signals incident on a uniform circular array