Antenna system for trilateral drone precise vertical landing

Antenna system for trilateral drone precise vertical landing

Víctor Araña-Pulido, Eugenio Jiménez-Yguácel, Francisco Cabrera-Almeida, Pedro Quintana-Morales

This article presents a radio frequency system that can be used to perform precise vertical landings of drones. The system is based on the three-way phase shift detection of a signal transmitted from the landing point.

The antenna system is designed by taking into account parameters such as landing tracking area, analog-to-digital converter (ADC) resolution, phase detector output range, antenna polarization, and the effect of antenna axial ratio.

The fabricated prototype consists of a landing point antenna that transmits a signal at 2.46 GHz, as well as a drone triantenna system that includes a phase shift detection circuitry, ADC, and a simple control program that provides the correction instructions for landing. The prototype provides an averaged output data rate (ODR) suitable for landing maneuvers (>300 Hz).

A simple system calibration procedure (detector output zeroing) is performed by aligning the antenna system. The measurements performed at different altitudes demonstrate both the correct operation of the proposed solution and its viability as an instrument for precision vertical landings.

Comments:	The paper has been accepted by IEEE Transactions on Instrumentation and Measurement, vol. 71, pp. 1-8, 2022
Subjects:	Systems and Control (eess.SY)
Cite as:	arXiv:2402.06011 [eess.SY]
	(or arXiv:2402.06011v1 [eess.SY] for this version)
	https://doi.org/10.48550/arXiv.2402.06011

Journal reference:	IEEE Transactions on Instrumentation and Measurement, vol. 71, pp. 1-8, 2022
Related DOI:	https://doi.org/10.1109/TIM.2022.3196949

Submission history

From: Pedro Quintana-Morales Dr [view email]
[v1] Thu, 8 Feb 2024 19:15:03 UTC (6,834 KB)

 Summary

Here are the key points from the document:

• The paper presents an antenna system and associated control system for precision vertical landing of drones. It builds on prior work proposing a triangular phase shift detection approach.
• The antenna system consists of a circularly polarized transmitting antenna on the landing point and three linearly polarized receiving antennas on the drone in a triangular configuration. This avoids amplitude variations during drone rotation.
• Design considerations include tracking area, ADC resolution, antenna polarization and axial ratio, detector output range, etc. A prototype is built and tested using patch antennas, Arduino controller, and commercial phase detector.
• The prototype demonstrates robust performance for landing maneuvers with high output data rate (>300Hz), suitable dynamic range (28dB), and proper functioning from 220cm height down to near field.
• A simple calibration procedure is proposed to zero the detector outputs and compensate for phase errors from hardware. This avoids needing external RF generators for calibration.
• Overall, the prototype demonstrates the viability of the triangular phase shift approach for precision vertical landing of drones, addressing implementation aspects absent from prior theoretical work.

Authors

Based on the author information in the paper:

The authors have collaborated on various Spanish and European research projects.

They cite their own prior theoretical work on the triangular phase shift detection approach for drone precision landing in the paper (reference [13]). So this current paper builds on their previous proposal by implementing and testing a prototype system.

• Víctor Araña-Pulido is an Assistant Professor at the University of Las Palmas de Gran Canaria (ULPGC). He is part of the Institute for Technological Development and Innovation in Communications (IDeTIC) there. His research interests include nonlinear microwave circuits and control systems.
• Eugenio Jiménez-Yguacel is an Associate Professor at ULPGC and part of IDeTIC. His work focuses on antenna and microwave circuit design, and digital communications.
• Francisco Cabrera-Almeida is an Assistant Professor at ULPGC and member of IDeTIC. His interests include electromagnetic modeling and radiowave propagation.
• Pedro Quintana-Morales is an Assistant Professor at ULPGC and member of IDeTIC. His work involves signal processing and data analysis.

Artifacts

The paper mentions the following artifacts related to the precision landing system prototype:

• Drone tri-antenna array: This consists of 3 linearly polarized patch antennas spaced 7cm apart in a triangular configuration, designed and fabricated by the authors.
• Landing point antenna: A circularly polarized patch antenna operating at 2.46 GHz, designed and fabricated by the authors.
• Phase detector circuitry: Uses a commercial integrated circuit (Analog Devices AD8302) to detect phase shifts between antenna signals.
• Control board: Uses an Arduino Uno microcontroller board to read phase detector voltages via ADC and generate flight control instructions.
• Control program: Algorithm implemented on the Arduino to calibrate the system, read voltages, determine position sector, and output flight maneuver commands. The flow diagram is provided.
• Sectorized chart and wheeled base: Used during experimental evaluation to move landing point antenna to different sectors and distances.

The specific antenna designs, detector circuit schematics, Arduino code, and sectorized chart are not provided in detail within the paper. But the text and block diagrams give an overview of the key hardware and software components designed by the authors as part of the prototype system.

Performance

The paper does not provide specific quantitative results for the landing accuracy achieved by the prototype system. However, some insights can be gleaned from the details provided:

• The system is designed to provide flight corrections based on continuous tracking of phase shifts between antenna signals as the drone approaches the landing point.
• The antenna spacing of 7cm was chosen to allow phase shift detection corresponding to drone movements as small as 0.746cm using the 10-bit ADC.
• The system was tested down to heights of 1.8cm above the landing point antenna, suggesting it can guide the drone with precision in close proximity.
• The high output data rate (>300Hz) enables real-time course corrections.
• Performance was validated across tracking areas from 7-110cm radii, demonstrating precision guidance over a range of Approach distances.

While no specific landing error measurements are reported, the high resolution tracking capability down to millimeter displacements, fast update rate, and testing at very close distances indicates the system can likely achieve high precision landing, perhaps within a few centimeters. But further quantitative evaluation would be needed to confirm the actual landing accuracy attainable.