Indian Journal of Science and Technology

Abstract

The paper considers the MUSIC and Capon methods for determination of radio radiation coordinates, possessing a superresolution property, which assumes that two signal sources spaced less than at the Rayleigh limit can be represented as individual peaks on the spatial direction finding relief graph. A computational burden problem arises in such spectrum estimation algorithms; it can be solved by the methods of building so-called orthogonal directional patterns, reducing computational complexity and antenna array dimension. A multibeam array pattern (spatial channel) is formed for this purpose, and then the signals are pre-processed by means of these spatial channels focused in a certain region. The paper gives numerical estimations of accuracy for determination of radio radiation source coordinates by the classical MUSIC and Capon methods, and also after preliminary transformation by orthogonal directional patterns (BS-MUSIC and BS-Capon) versus signal/noise ratio, the number of beams and averaging time of the correlation matrix. A great number of methods of mutually orthogonal spatial channel formation are presented; among them the most well-known discrete Fourier transform, spherical sequences and Taylor series expansion. It is worth noting that to date no comparative studies of the accuracy characteristics of such methods (BS-MUSIC and BS-Capon) has been performed. It is found that the accuracy of the BS-MUSIC and BS-Capon methods increases with the increase in the number of spatial channels from four to five. In this case the accuracy of the method for channel generating by spherical discrete sequences is the highest in the majority of the considered interference cases.
Keywords: Digital Antenna Array, Orthogonal Directional Patterns, Superresolution, Wireless Direction Finding