Closed-Form Angle Estimation with Circular Arrays/Apertures for Mobile/Cellular Communications and Surveillance Radar

数字通信行业目前正投入大量资源来开发和实验验证要部署在包括未来商用汽车在内的移动的通信车辆上的原型天线阵列，作为基于它们各自的空间位置在频率上共置的信号之间进行区分的手段。 在小口径移动的通信单元上，均匀圆阵（UCA）的几何形状是理想的，因为它相对于方位角的旋转不变性。 这项研究是基于最近的一项突破，主要研究者：一个简单的，封闭的形式的算法与UCA，提供自动配对的源方位角和仰角估计一起使用的发展。 相比之下，用于2D到达角估计的算法到目前为止需要昂贵的谱搜索、多维优化问题的迭代解决方案或用于相对于多个不同阵列轴中的每一个对方向余弦估计的自组织方案。 注意，UCA-ESPRIT与ESPRIT的根本不同之处在于，它不是基于位移不变性阵列结构，而是基于相位模式激励，并且取决于贝塞尔函数之间的递归关系。 UCA-ESPRIT的理论性能分析正在进行中。 这将被证明是非常有用的预测其性能在移动的通信环境。 新的战略，将相互耦合的影响也正在开发。 UCA-ESPRIT的真实的世界性能将用目前正在马德里理工大学建造的原型圆形天线阵的实验数据进行评估，该天线阵用于与国际海事卫星组织卫星系统进行移动的海上通信。 UCA-ESPRIT的填充圆形阵列的适应也正在开发中。

The digital communications industry is currently investing a plethora of resources towards the development and experimental verification of prototype antenna arrays to be deployed on mobile communication vehicles, including the commercial automobile of the future, as a means of discriminating amongst signals co-located in frequency based on their respective spatial locations. Given the small aperture on a mobile communications unit, the uniform circular array (UCA) geometry is ideal due to its rotational invariance with respect to azimuth. This research is based on a recent breakthrough by the principal investigator: the development of a simple, closed form algorithm for use in conjunction with a UCA that provides automatically paired source azimuth and elevation angle estimates. In contrast, the algorithms for 2D arrival-angle estimation to date have required expensive spectral searches, iterative solutions to multidimensional optimization problems, or ad-hoc schemes for pairing direction cosine estimates with respect to each of a number of different array axes. Note that UCA-ESPRIT is fundamentally different from ESPRIT in that it is not based on a displacement invariance array structure but rather is based on phase mode excitation and hinges on a recursive relationship between Bessel functions. A theoretical performance analysis of UCA-ESPRIT is being conducted. This will prove extremely useful for predicting its performance in a mobile communications environment. Novel strategies for incorporating mutual coupling effects are being developed as well. The real world performance of UCA-ESPRIT will be assessed with experimental data from a prototype circular antenna array currently being built at the Polytechnic University of Madrid for mobile sea communications with the INMARSAT satellite system. Adaptations of UCA-ESPRIT for filled circular arrays are also being developed.