Design of robust aperiodic antenna array formations for micro-UAV swarms

Abstract

In recent years there has a been a great interest in micro-UAV (Unmanned Aerial Vehicle) swarms due to their remote sensing and intelligence gathering capabilities. There are also numerous civilian applications for these swarms such as environmental monitoring and pollution control. For the micro-UAV swarms considered here, each aircraft in the swarm is assumed to host a single antenna element such that collectively they form an array. One of the major challenges in the design of micro-UAV swarm arrays lies in the fact that, due to safety reasons and to avoid possible collision between the micro-UAVs, the minimum separation distance between the elements of the swarm is usually required to be several wavelengths. Thus typical periodic planar arrays will not be very useful, since for periodic arrays, increasing the minimum separation distance beyond one wavelength will lead to undesirable grating lobes in the radiation pattern. In this paper, a new design methodology is suggested to create robust antenna array configurations for application in micro-UAV swarms. The method is based on aperiodic tiling of the plane and, as part of the design process, employs a modified version of the perturbation method first introduced in [1]. These modifications add more degrees of freedom to the design process, thereby making the optimization of such arrays slightly more complex; however they were also found to vastly improve the performance results. Once these arrays have been designed, the positional error of the elements associated with turbulence effects or other factors are studied. Compensation algorithms are then developed by applying the phase correction method proposed in [2]. We show that the phase correction algorithm can be applied very effectively to these aperiodic arrays to eliminate the errors around the main beam while still maintaining their grating lobe suppression and low sidelobe properties. It is also demonstrated that when applied to periodic arrays, the phase correction algorithm is not effective in eliminating grating lobes.