Direction of arrival estimation methods for smart antenna systems

Determination of signal sources has been an important problem in military applications such as radar systems, location finding systems and electronic warfare systems. In daily life, signal source estimation systems are used, for example, in mobile communication systems, for the determination of mine reservations, for the detection of illegal radio broadcasting and for finding the lost mountaineers.When the systems first appeared, they could determine the position of only one signal source. Nowadays, with the development of subspace techniques, it has been possible to determine the positions of multiple signal sources. MUSIC and ESPRIT algorithms are two of the most widely known and used signal source estimation techniques. This study aims the comparison of the performances of these two techniques.In this study, the signals coming toward uniform linear antenna arrays are first estimated using MUSIC algorithm. Then, estimation is performed with ESPRIT algorithm for the same antenna structure. Estimation performances of the two techniques related to signal arrival angle are compared with each other.The obtained results show that MUSIC algorithm gives more accurate and definite results for moderately low signal to noise ratios, whereas ESPRIT algorithm gives accurate results for moderately high signal to noise ratios. On the other hand, ESPRIT algorithm provides ease of calculation, decrease in capacity and cost.Key Words : Direction Finding, DOA, MUSIC Method, ESPRIT Method, Linear antenna array, Subspace method