Swarm Localization and Bearing Estimation based on Multimode Antennas

• Applicants: Professor Dr.-Ing. Uwe-Carsten Fiebig; Professor Dr.-Ing. Peter A. Höher
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 290848173

In the area of exploration, swarm systems are becoming more important. Concerning the physical layer, the main challenge is not just to establish reliable high-rate communication links between swarm elements, but also to constitute precise localization of the swarm elements. In numerous preliminary works, trend-setting swarm localization algorithms have been developed and partially tested in field trails. In these investigations it has been revealed that the estimation error can be reduced by means of antenna arrays. Antenna arrays additionally offer the possibility of an estimation of the bearing of a swarm element (in terms of the roll-pitch-yaw angle). Classically, inertial navigation is performed by means of expensive navigation-grade components like gyroscope, acceleration sensor and compass.In the first two years of this joint research project between DLR Oberpfaffenhofen and CAU Kiel, an innovative solution has been proposed and investigated: A classical antenna array has been substituted by a so-called planar multimode antenna. Multimode antennas are radiators (for example a printed circuit board), where multiple modes can be excited mutually independent. Hence, different radiation patterns can be generated. For the first time, it has been explored how multimode antennas behave concerning localization estimation and bearing estimation. The solved work packages are as follows: (1) Modeling of a multimode antenna (by means of the array interpolation technique and wavefield modeling) as a virtual antenna array with equidistant antenna elements, (2) assessment of the accuracy of localization estimates given a multimode antenna, (3) estimation of the bearing based on a multimode antenna, (4) development of an optimal signaling waveform for joint localization and bearing estimation, (5) joint localization and bearing estimation for swarm systems, and (6) overall system design.In the third and last project year the following working packages are drafted: (7) Influence of phase centers on position and bearing estimates: For simple model assumptions, firstly the approximate positions of angle and mode dependent phase centers of a multimode antenna shall be calculated. Based on this, the impact of the phase centers on estimation precision shall be investigated. (8) Data acquisition: The radiation characteristic of a multimode antenna shall be determined in an anechoic RF chamber. Afterwards, mobile measurements in an outdoor environment using a rover are planned. (9) Experimental verification: The predicted phase centers and the theoretically calculated estimation errors finally shall be verified on the basis of experimentally acquired data.

• DFG Programme: Research Grants