Lehrstuhl für Informations- und Codierungstheorie

Swarm Localization and Orientation Estimation based on Multimode Antennas

DFG HO 2226/17-1 and FI 2176/1-1


Exployting an automated unmanned platform is a decisive alternative to human employment in order to perform exploration missions in severe environments. Typically, a swarm of rovers or aerial vehicles can perform such missions. Reliability, range, precision, and aperture of the exploration are few of numerous advantages that a swarm offers in comparison to a single explorer. In most cases, a communication infrastructure is not available in the exploration area. Hence, the assigned swarm should be able to communicate and navigate the environment utilizing its own communication system.

In this project, we focus on solving the problem of estimating the position and orientation of rover units in a swarm constellation based on a novel antenna design, dubbed Multi-Mode Antennas. In contrast to traditional antennas, a multi-mode antenna is equipped with multiple ports. Each port excites a unique mode, and each mode corresponds to a unique radiation patterns. In other words, a multi-mode antenna is a single physical radiator that emits several radiation patterns simultaneously.

This property is attractive for the purpose of positioning, because a multi-mode antenna of M-ports mimics an antenna array of M elements, while offering a compact and robust structure suitable for mounting on a rover.

Towards the purpose of position and orientation estimation based on multi-mode antennas, it is necessary to design a precise model that simulates the multi-mode antenna accurately. The success of this step allows the application of conventional signal processing methods for position and orientation estimation. Furthermore, a well designed model provides information of the antenna spatial response at any arbitrary angle in space based only on calibration measurements or simulations of a rough resolution.

Next, the performance of the multi-mode antenna in finding the direction of arrival (DoA) and the orientation angles (roll-pitch-yaw) shall be examined. Efficient DoA and orientation estimation algorithms shall be applied using the multi-mode antenna model. Furthermore, it is necessary to design an optimal signal form for joint positioning and orientation estimation as well as the corresponding Cramer-Rao Bound (CRB) as a benchmark to evaluate the results.

Moreover the position of the phase center of each mode besides the effect of the phase center variations on the accuracy of positioning shall be studied. This represents a challenge since the phase center variations are subject to the DoA among other parameters. Therefore, a compensation of these variations is inevitable in order to obtain precise results in the positioning system.

Finally, the studied methods and the simulation results shall be verified through a series of field experiments. The experiments shall employ a multi-mode antenna prototype to test the proposed methods and compare the real world performance with the theoretical performance of the designed position and orientation estimation system.

This project is a joint work between Christian-Albrechts-Universität zu Kiel (CAU) and the German Aerospace Center (DLR), Oberpfaffenhofen:


Selected References:

[1] S. Alkubti Almasri, N. Doose, and P. A. Hoeher, “Parametric direction-of-arrival estimation for multi-mode antennas,” in Proc. 14th Workshop on Positioning, Navigation and Communications (WPNC), Bremen, Germany, Oct. 2017.

[2] R. Pöhlmann, S. Zhang, T. Jost, and A. Dammann, “Power-based directionof-arrival estimation using a single multi-mode antenna,” in Proc. 14th Workshop Positioning, Navigation and Communications (WPNC), Bremen, Germany, Oct. 2017.

[3] R. Pöhlmann, S. Zhang, K. A. Yinusa, and Ar. Dammann “Multi-mode antenna specific direction-of-arrival estimation schemes,” in Proc. IEEE 7th Int. Workshop ComputationaAdvances in Multi-Sensor Adaptive Processing (CAMSAP), Curacao, Dec. 2017.

[4] R. Pöhlmann, S. Zhang, A. Dammann, and P. A. Hoeher, “Fundamental limits for joint relative position and orientation estimation,” in Proc. IEEE Int. Conf. CommunicationsWorkshops (ICC Workshops), Kansas City, Missouri, May 2018.

[5] R. Pöhlmann, S. Zhang, A. Dammann, and P. A. Hoeher, “Fundamental limits for joint relative position and orientation estimation with generic antennas.” in Proc. 26th European Signal Processing Conf. (EUSIPCO), Rome, Italy, Sept. 2018.

[6] S. Alkubti Almasri, R. Pöhlmann, N. Doose, P. A. Hoeher, and A. Dammann, “Modeling Aspects of Planar Multi-Mode Antennas for Direction-of-Arrival Estimation,” IEEE Sensors Journal, vol. 19, no. 12, pp. 4585-4597, June, 2019.

[7] R. Pöhlmann, S. A. Almasri, S. Zhang, T. Jost, A. Dammann and P. A. Hoeher, "On the Potential of Multi-Mode Antennas for Direction-of-Arrival Estimation," IEEE Transactions on Antennas and Propagation, vol. 67, no. 5, pp. 3374-3386, May 2019.