Improving the Radio Direction-Finding Accuracy in Smart Antenna Systems for Non-Uniform Angular Distribution Based on a Three Dimensional Spherical Dome Geometry

This paper presents a novel 3D spherical dome geometry to improve the accuracy of simultaneous direction-finding for the azimuth and the elevation angles for specific applications. The estimation of the arrival angle is implemented using the Multiple-Signal Classification (MUSIC) algorithm with considering the coupling effect between the elements. To evaluate the performance, the accuracy of direction-finding using the proposed geometry is compared with more common geometries such as cylindrical arrays and triangular prism with the same volume. The angular estimation accuracy is calculated based on the root mean square error using the Monte-Carlo simulations, and the simulation results indicate that the proposed geometry reduces the estimation error by 30 percent and 22 percenent compared with cylindrical and prism geometries respectively, and the spherical dome geometry has acceptable estimation accuracy compared to the Cramer-Rao lower bound criterion for this geometry. The simultaneous direction-finding accuracy for both azimuth and elevation angles in the considered scenario, using the 3D spherical dome geometry, has been calculated as 0.84 degrees (for 100 number of snapshots and signal-to-noise ratio of 7 dB, taking into account the coupling effects between the elements).The use of this geometry for specific applications (limited azimuth and elevation angles) provides a significant improvement in angle of arrival estimation error, especially by reducing the coupling effects between the ‌elements. The accurate estimation of the azimuth and the elevation angles of the signal and the interferences makes this geometry suitable for beamforming applications in new generations of mobile communications.