Faculty Publications
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Publications by NITK Faculty
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Item Biomimetics and emerging trends in aviation technology(IJETAE Publication House, 2020) Sreeramagiri, S.V.S.; Bhavani, T.This article throws light on the influences and applications of biomimetics in Aviation Technology. A review of the emerging trends and pathbreaking technologies of aviation mechanisms, design, materials for aerial vehicles, guidance systems, greener technologies for aerial vehicles is presented. © 2021 International Journal of Emerging Technology and Advanced Engineering. All Rights Reserved.Item All-Optical UAV-Based Triple-Hop FSO-FSO-VLC Cooperative System for High-Speed Broadband Internet Access in High-Speed Trains(Institute of Electrical and Electronics Engineers Inc., 2023) Aarthi, A.; Bhargava Kumar, L.B.; Krishnan, P.; Natarajan, R.; Jayakody, D.N.K.In this paper, we proposed an unmanned aerial vehicle (UAV) based all optical triple hop mixed free space optical-free space optical-visible light communication (FSO-FSO-VLC) system for broadband internet access in high-speed train applications. The system consists of triple hops from gateway to the UAV, UAV to train and train to the end user. Two decode and forward relays are mounted on the UAV and train respectively to transmit the data between the gateway to the end-users. The first hop between gateway to UAV consist of FSO link which follows M-distribution. The second hop between the UAV to train consists of FSO link and is modelled using Gamma-Gamma distribution which takes into account both atmospheric turbulence and pointing errors due to position/orientation deviation. The third hop between the train and end user is connected using VLC link and it is mathematically modelled using Lambertian emission distribution. The relays map the incoming signal on the FSO links and send it down to the user inside the train via the VLC downlink. We derived the closed form expressions for average bit error rate and outage probability of the proposed system. This paper investigates the effects of atmospheric turbulence, field of view, beam divergence angle, displacement deviation variance, optical concentrator gain, number of access point, and modulation schemes on system performance. First time, we proposed all-optical system which offers high data rate and low transmission delay. © 2013 IEEE.Item Solar Photovoltaic Hotspot Inspection Using Unmanned Aerial Vehicle Thermal Images at a Solar Field in South India(MDPI, 2023) Umesh, P.; Kashyap, Y.; Baxevanaki, E.; Kosmopoulos, P.The sun is an abundant source of energy, and solar energy has been at the forefront of the renewable energy sector for years. A way to convert it into electricity is by the use of solar cells. Multiple solar cells, connected to each other, create solar panels, which in their turn, are connected in a solar string, and they create solar farms. These structures are extremely efficient in electricity production, but also, cells are fragile in nature and delicate to environmental conditions, which is the reason why some of them show discrepancies and are called defective. In this research, a thermal camera mounted on a drone has been used for the first time in the solar farm operating conditions of India in order to capture images of the solar field and investigate solar panels for defective cells and create an orthomosaic image of the entire area. This procedure next year will be established on an international scale as a best practice example for commercialization, providing effortless photovoltaic monitoring and maintenance planning. For this process, an open source software WebODM has been used, and the entire field was digitized so as to identify the location of defective panels in the field. This software was the base in order to provide and analyze a digital twin of the studied area and the included photovoltaic panels. The defects on solar cells were identified with the use of thermal bands, which record and point out their temperature of them, whereas anomalies in the detected temperature in defective solar cells were captured using thermal electromagnetic waves, and these areas are mentioned as hotspots. In this research, a total number of 232.934 solar panels were identified, and 2481 defective solar panels were automatically indicated. The majority of the defects were due to manufacturing failure and normal aging, but also due to persistent shadowing and soiling from aerosols and especially dust transport, as well as from extreme weather conditions, including hail. The originality of this study relies on the application of the proposed under development technology to the specific conditions of India, including high photovoltaic panels wear rates due to extreme aerosol loads (India presents one of the highest aerosol levels worldwide) and the monsoon effects. The ability to autonomously monitor solar farms in such conditions has a strong energy and economic benefit for production management and for long-term optimization purposes. © 2023 by the authors.Item Enhancing Smart City Connectivity: Implementing Channel-Adaptive Strategies for FSO-Based Drone-Assisted Mobile Access Networks in Urban Environments(Institute of Electrical and Electronics Engineers Inc., 2025) Aarthi, G.; Bhargava Kumar, L.; Vaidya, M.; Nema, S.; Krishnan, P.; Sangeetha, A.; Natarajan, R.; Karthikeyan, K.The global surge in urbanization has catalyzed the evolution of smart city infrastructures, characterized by expansive interconnected networks spanning vast urban landscapes. To address the connectivity challenges inherent in smart city environments, this study advocates for the utilization of autonomous aerial vehicles (AAVs) as an alternative to traditional mobile air base stations. Leveraging Free-Space Optical (FSO) links for downlink transmission from AAVs to users, the proposed system confronts atmospheric turbulence and pointing loss impairments. In this context, the study explores the average spectral efficiency (ASE) performance of the proposed FSO-based Drone-Assisted system employing various channel adaptive techniques, including Optimal Rate Adaptation, Channel Inversion with Fixed Rate, Optimal Power and Rate Adaptation, and Truncated Channel Inversion with Fixed Rate. Additionally, the investigation underscores the impact of factors such as link range, coverage distance, AAV orientation fluctuation standard deviation, AAV position vibration standard deviation, and beam divergence on system performance. By elucidating these aspects, the research aims to contribute valuable insights into the optimization of smart city connectivity, paving the way for enhanced communication infrastructure in urban environments. Notably, the study achieved a maximum ASE of 101 bits/s/Hz using the TIFR adaptation scheme, underscoring the efficacy of the proposed approach. © 2013 IEEE.Item SLIPT Enabled Ground-to-UAV FSO Communication for SAGNET in 6G-IoT Systems(Institute of Electrical and Electronics Engineers Inc., 2025) Kavitha, K.; Kavitha, K.; Angayarkanni, V.; Krishnan, P.The development of 6G-IoT aims to provide seamless connectivity across space, air, ground, sea, and underwater networks. Uncrewed Aerial Vehicles (UAVs) with Free-Space Optical (FSO) communication are crucial in these networks, but their power limitations challenge sustained operation. This paper explores Simultaneous Lightwave Information and Power Transfer (SLIPT) for Ground-to-UAV (G2U) FSO communication, focusing on four methods: AC-DC separation (ADS), time switching (TS), power splitting (PS), and time switching-power splitting (TSPS). We derive closed-form expressions for harvested energy, Symbol Error Rate (SER), and outage probability under a generalized Málaga distribution, considering atmospheric attenuation, turbulence, and pointing errors. Our study examines the impact of SLIPT methods on harvested energy and SER, analyzing link distances, atmospheric conditions, pointing errors, and weather. Optimal beamwidth and receiver Field of View (FOV) values are identified to maximize energy and minimize SER. Findings show the TSPS method yields the highest harvested energy, achieving 0.04 mJ under strong turbulence, due to its dual-phase approach. The proposed SLIPT methods enhance UAV energy efficiency and improve SER performance, achieving a SER of 10-4 at an SNR of 30 dB, providing key insights for 6G-IoT optimization. © 2017 IEEE.