Smart Relay Architecture for Over-the-Horizon High Quality Communications With Unmanned Aerial Vehicles

Abstract

This paper presents a system architecture to accomplish over-the-horizon communications with medium-sized unmanned aerial vehicles (UAV) in order to enhance its autonomy and maximum range. This architecture is based on using a second UAV as a communication relay with a compact active circular array with separated transmitting and receiving elements at C-band. The designed active feeding network provides switching capabilities in order to selectively activate these elements depending on the desired direction of the antenna beam, achieving maximum equivalent isotropic radiated power (EIRP) in transmission and maximum antenna gain in reception. In this way, a bidirectional long-range link for telemetry, telecommand, and high-resolution video can be deployed between UAVs providing high quality of service, reliability, and moderate data throughput at an affordable cost. Based on the measurements of a manufactured prototype, the maximum range of the deployed air-air link using the designed system is estimated in 20 km, considerably increasing the performance of current systems based on the use of omnidirectional antennas onboard UAVs.INDEX TERMS Antenna array, beam steering, beam-switching, microwave circuits, over-the-horizon communications, patch antennas, relay architecture, switched circuit, unmanned aerial vehicle (UAV).

A novel elliptic trajectory formula for active RSSI-based antenna tracking algorithm

“…This defect can be overcome by supplementing a steering system to the antenna which builds communication between UAVs and GCS. This system is known as antenna tracker (AT) which includes both its steering operation and tracking algorithm (Awang Bayu, 2017). Due to high gain operation, tracking performance of AT is very critical for continuous air-to-ground (A2G) telemetry.…”

“…The drawback was the need for multiple receivers. Furthermore, RSSI tracking techniques are quite often used for direction or position detection, despite the need for antenna array topologies or multiple receiving devices in previous algorithms (Avilés-Viñas et al, 2022; Blazquez-Garcia et al, 2019; Chen et al, 2020; Le et al, 2020; Yucer et al, 2020). As an additional consideration, the path loss model requires coefficients to be re-expressed for different measurement conditions or antenna.…”

An investigation on the structural vibrations of multi-rotor passenger drones

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