Department Publications

Unmanned aerial vehicles (UAVs)-assisted communication systems are considered as a promising technology in diverse verticals. This paper studies the deployment of UAVs in wireless sensor network (WSN) systems. Considering the energy-constrained nature of the wireless sensors, we have proposed a multi-UAV deployment algorithm that minimizes the maximum power transmitted among the sensor nodes (SN) for given minimum data collection rate, minimum data-transferring rate, maximum power and height constraints. The problem is divided into three subproblems in order to reduce the complexity involved in solving them as a single problem. The subproblems are UAV-SN association, 2D positioning of the UAVs and the altitude optimization of the UAVs. Each subproblem is optimized by fixing other parameters as constant. First, the UAV-SN association is addressed using a customized Gale–Shapley …

With growing applications of drones, there is a demand for drone audition functionality that allows microphone arrays to be embedded into or attached to the body of drones for sound source localization and signal enhancement. In practical acoustical environments, the performance of drone audition is degraded due to the free-field sound propagation assumption. In this paper, we propose (i) a method for modeling the scattering and diffraction of a drone body beyond free-field propagation as a Drone-Related Transfer Function (DRTF), and (ii) a practical method to estimate the DRTF coefficients using circular loudspeaker arrays. The method incorporates the acoustic reciprocity principle and a finite order spherical harmonic expansion by utilizing a discrete set of measurements by multiple loudspeaker placements on circular arrays. We validate our DRTF model and parameterization method on a known rigid sphere …

Drone swarms pose a threat to national security. There is growing interest in an “Iron Dome for America” to protect against weaponized drones, missiles and other threats. The sensing, classification and characterization of a swarm of drones-typically with hundreds of devices flying in close proximity to each other-is a challenging radar and AI/ML problem. In this paper, we report on early work on using state-of-the-art AI/ML algorithms with advanced digital signal processing towards demonstrated capabilities for UAS swarm detection and classification at the laboratory scale. An automotive grade 77 GHz FMCW radar evaluation board, and commercial (toy) micro drones are used for experimentation. The FMCW pulses use 3 GHz of bandwidth. All experiments are conducted within a short range whereas long range experiments reserved for future work.

The quadrotor is an underactuated, nonlinear system that presents significant challenges in both modeling and control design. This work develops a decoupled control framework based on the translational (Newtonian) and rotational (Eulerian) dynamics of the quadrotor. A Linear Quadratic Gaussian (LQG) regulator is implemented for control, with two extended Kalman filters employed for state estimation in the respective dynamic subsystems. The full design process, from dynamic modeling to flight simulation presented in detail. Key elements include nonlinear simulation, model linearization, state-space representation, feedforward compensation, Linear Quadratic Regulator (LQR) gain tuning, actuator dynamics, sensor noise, LQG design, and extended Kalman filter. The limitations of applying linear control to a nonlinear system are also presented.