Design and early development of a UAV terminal and a ground station for laser communications

Abstract

A free-space laser communication system has been designed and partially developed as an alternative to standard RF links from UAV to ground stations. This project belongs to the SINTONIA program (acronym in Spanish for low environmental-impact unmanned systems), led by BR&TE (Boeing Research and Technology Europe) with the purpose of boosting Spanish UAV technology.A MEMS-based modulating retroreflector has been proposed as a communication terminal onboard the UAV, allowing both the laser transmitter and the acquisition, tracking and pointing subsystems to be eliminated. This results in an important reduction of power, size and weight, moving the burden to the ground station. In the ground station, the ATP subsystem is based on a GPS-aided two-axis gimbal for tracking and coarse pointing, and a fast steering mirror for fine pointing. A beacon-based system has been designed, taking advantage of the retroreflector optical principle, in order to determine the position of the UAV in real-time. The system manages the laser power in an optimal way, based on a distance-dependent beam-divergence control and by creating two different optical paths within the same physical path using different states of polarization.

A review on pointing, acquisition, and tracking approaches in UAV-based fso communication systems

“…In Carrasco-Casado et al (2011a, 2011b, a UAV-to-ground PAT mechanism for FSO communications system is proposed. The main component of the PAT mechanism on a UAV is the micro-electromechanical systems (MEMS) retro-reflector mirror, which is used to attain the least size, weight, and payload power.…”

Frontier Progress of Unmanned Aerial Vehicles Optical Wireless Technologies

“…The ATP mechanism is mainly divided into the following types, frame-based, mirror-based, frame-mirror hybrid, adaptive optics, liquid crystal, and RF/FSO hybrid [ 103 ]. With different scenarios, different ATPs will choose, for example, a larger pointing range is required for OWC between satellites and drones, whose communication link is the ATP mechanism of framework-based for its first choice [ 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ]. However, because of the self-load of the rotating frame, this ATP mechanism is not suitable for the load limitation of small UAVs.…”

Energy‐efficient full‐duplex UAV relaying networks: Trajectory design for channel‐model‐free scenarios

“…Such applications are facilitated by the low cost, deployment flexibility, and full controllability in 3D airspaces of UAVs. Compared to terrestrial systems, UAV wireless systems offer several advantages, including superior link quality for communication channels [3] and greater link connection flexibility [4]. Therefore, UAV‐enabled communications are expected to improve network capacity and increase cell coverage in emerging G networks [5].…”

“…Such applications are facilitated by the low cost, deployment flexibility, and full controllability in 3D airspaces of UAVs. Compared to terrestrial systems, UAV wireless systems offer several advantages, including superior link quality for communication channels [3] and greater link connection…”