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

数字通信业目前正在投入大量资源，用于开发和实验验证将部署在移动通信车辆(包括未来的商用汽车)上的原型天线阵列，作为一种基于信号各自的空间位置在频率上共同定位的信号之间的区分手段。考虑到移动通信单元上的小孔径，均匀圆形阵列(UCA)的几何形状是理想的，因为它相对于方位角具有旋转不变性。这项研究是基于主要研究人员最近的一项突破：开发了一种简单、封闭的算法，与UCA一起使用，该算法自动提供成对的震源方位角和仰角估计。相反，到目前为止，用于2D到达角估计的算法需要昂贵的谱搜索、多维优化问题的迭代解、或者关于多个不同阵列轴中的每一个的配对方向余弦估计的自组织方案。值得注意的是，UCA-ESPRIT与ESPRIT的根本不同之处在于，它不是基于位移不变的阵列结构，而是基于相位模式激励和贝塞尔函数之间的递归关系。对UCA-ESPRIT的性能进行了理论分析。这将被证明对预测其在移动通信环境中的性能非常有用。此外，还在制定纳入相互耦合效应的新战略。UCA-ESPRIT的真实世界性能将使用马德里理工大学目前正在建造的用于与国际海事卫星组织卫星系统进行海上移动通信的圆形天线阵原型的实验数据进行评估。UCA-ESPRIT对填充圆形阵列的改编也在开发中。

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.