| Popis: |
Phased array antennas have been extensively used in radar systems. Each application requires an adequate design, to comply with specific requirements that involves both the radiation pattern as well as the beams spacing. Within this context, Orthogonal Beamforming arises as an interesting solution for surveillance radar applications. Besides optimum sidelobe isolation around the center of the beams, the orthogonality provides better coverage efficiency using the minimum number of beams to fill a given angular sector. On the other hand, since a single target can be detected in multiple beams, angular estimation in such configuration poses as a challenge when no windowing is applied to the radiation pattern (e.g. in long range applications) and the system can not cope with the additional computational burden of multi channel estimation. In the present work, closed form expressions describing the target's angular position in linear phased array systems with orthogonal beam shapes are derived, allowing full modeling of the beams, including side lobes positions. A combined algorithm for angular estimation is then proposed considering surveillance phased array systems with orthogonal beam spacing. Finally, the proposed algorithm performance, in terms of accuracy and precision, is evaluated using a Monte Carlo simulation approach, and compared to the simple centroid standalone solution. |
