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The advent of 6G technology will transforms aviation, particularly in the realm of aircraft health monitoring systems (AHMSs). This paper explores the transformative potential of 6G in enhancing real-time data exchange, predictive maintenance, and overall communication efficiency within the aviation sector. By using ultra-fast data transmission, low latency, and advanced AI integration, 6G enables the development of a unified AHMS architecture that significantly improves aircraft safety, operational efficiency, and reliability. The proposed eight-layer AHMS model, incorporating digital twins, federated learning, and edge computing, showcases how 6G can revolutionize aircraft maintenance by providing continuous, real-time monitoring and decision-making capabilities. [ABSTRACT FROM AUTHOR]

Civil aviation is an important part of public transportation. However, the wireless communication systems used in the approach and tower control phases of traffic control are susceptible to external interference, posing a threat to flight safety. Traditional communication interference solutions are time-consuming and require specialized technicians to troubleshoot. To solve this problem, we propose a real-time method for monitoring abnormal signals and detecting interference sources during aviation radio communications. The method consists of three steps: real-time blind source signal separation using cubic polynomial fitting, abnormal signal monitoring based on discriminative signal residence time, and using Pearson correlation coefficients to identify abnormal interference sources. This comprehensive approach effectively ensures the frequency safety of aviation radio communications. Experiments conducted at different locations in real airport environments demonstrate that this method can efficiently identify the signal bands and their interference sources. [ABSTRACT FROM AUTHOR]

This paper presents a new design for a multimode fusion communication system, aimed at tackling the complexities of modern aeronautical communication. The system integrates multiple communication technologies, such as ad hoc networking, 5G, BeiDou satellite, RTK positioning, and ADS-B broadcasting. This integration effectively solves the problem of increasing the size and weight of aviation communication equipment while also improving the efficiency and security of data communication. The study demonstrates that the implementation of this fusion communication system can lead to the development of more efficient and intelligent avionics equipment in the future, thereby offering robust technical support for flight safety. [ABSTRACT FROM AUTHOR]

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study addresses the challenges that high-noise environments and complex multi-speaker scenarios present in civil aviation radio communications. A novel radiotelephone communications speaker diffraction network is developed specifically for these circumstances. To improve the precision of the speaker diarization network, three core modules are designed: voice activity detection (VAD), end-to-end speaker separation for air–ground communication (EESS), and probabilistic knowledge-based text clustering (PKTC). First, the VAD module uses attention mechanisms to separate silence from irrelevant noise, resulting in pure dialogue commands. Subsequently, the EESS module distinguishes between controllers and pilots by levying voice print differences, resulting in effective speaker segmentation. Finally, the PKTC module addresses the issue of pilot voice print ambiguity using text clustering, introducing a novel flight prior knowledge-based text-related clustering model. To achieve robust speaker diarization in multi-pilot scenarios, this model uses prior knowledge-based graph construction, radar data-based graph correction, and probabilistic optimization. This study also includes the development of the specialized ATCSPEECH dataset, which demonstrates significant performance improvements over both the AMI and ATCO2 PROJECT datasets. [ABSTRACT FROM AUTHOR]

The L-band digital aeronautical communication system (LDACS) is one of the candidate technologies for future broadband digital aeronautical communications, utilizing the unused L-band spectrum between distance measuring equipment (DME) channels. However, the higher signal power of DME complicates LDACS implementation. This paper proposes an advanced DME mitigation approach for the LDACS, integrating joint direction of arrival (DOA) estimation with adaptive beamforming techniques. The proposed method begins by exploiting the cyclostationary characteristics of signals, accurately obtaining the preliminary direction of the LDACS signal using the Cyclic-MUSIC method. Subsequent precise steering vectors (SVs) are selected through Capon spectrum search, followed by the reconstruction of the interference plus noise covariance matrix (INCM). Using the obtained SV and INCM, the weight vector is calculated and beamforming is performed. Simulation results validate that the proposed method not only accurately estimates the direction of LDACS signal but also efficiently mitigates DME interference, demonstrating a superior performance and reduced algorithmic complexity, even in scenarios with lower signal-to-noise ratios (SNRs) and the presence of DOA estimation errors. Additionally, the proposed method achieves a low bit error rate (BER), further validating its ability to ensure communication quality and enhance the reliability of LDACS. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigates the impact of weather conditions on flight performance and aviation communication. By analyzing the complex relationship between meteorological factors and aviation operations, the importance of understanding and properly managing aviation weather is highlighted. In addition, it examines how communications between pilots and air traffic controllers are influenced by weather conditions and how they can affect flight safety and efficiency. [ABSTRACT FROM AUTHOR]

When constructing a wireless communication network, the line of sight of radio waves is limited by the terrain features in a ground communication network. Also, satellite communication networks face capacity limitations and are vulnerable to jamming. Aviation communication networks can solve the above-mentioned problems. To construct seamless aviation communication networks, fast counterpart location estimation and efficient beam steering performance are essential. Among various techniques used for searching the counterpart's location, the monopulse technique has the advantage of quickly estimating the location through a simplified procedure. However, the nonlinear characteristics of the monopulse ratio curve, which are inevitably caused by the general antenna beam shape, both limit the location estimation range and reduce the estimated location accuracy. To overcome these limitations, a method that improves the estimation accuracy and extends the range by correcting the sum and difference patterns using the beamforming technique of active phased array antennas was proposed. An antenna system model suitable for aviation communication networks was presented, and the proposed model was experimentally proven to be effective. An average angle error of 0.021° was observed in the estimation of the accuracy of the antenna location. [ABSTRACT FROM AUTHOR]

In light of the escalating demand and intricacy of services in contemporary terrestrial, maritime, and aerial combat operations, there is a compelling need for enhanced service quality and efficiency in airborne cluster communication networks. Software-Defined Networking (SDN) proffers a viable solution for the multifaceted task of cooperative communication transmission and management across different operational domains within complex combat contexts, due to its intrinsic ability to flexibly allocate and centrally administer network resources. This study pivots around the optimization of SDN controller deployment within airborne data link clusters. A collaborative multi-controller architecture predicated on airborne data link clusters is thus proposed.Within this architectural framework, the controller deployment issue is reframed as a two-fold problem: subdomain partitioning and central interaction node selection. We advocate a subdomain segmentation approach grounded in node value ranking (NDVR) and a central interaction node selection methodology predicated on an enhanced Artificial Fish Swarm Algorithm (AFSA). The advanced NDVR-AFSA (Node value ranking-Improved artificial fish swarm algorithm) algorithm makes use of a chaos algorithm for population initialization, boosting population diversity and circumventing premature algorithm convergence. By the integration of adaptive strategies and incorporation of the genetic algorithm’s crossover andmutation operations, the algorithm’s search range adaptability is enhanced, thereby increasing the possibility of obtaining globally optimal solutions, while concurrently augmenting cluster reliability. The simulation results verify the advantages of the NDVR-IAFSA algorithm, achieve a better load balancing effect, improve the reliability of aviation data link cluster, and significantly reduce the average propagation delay and disconnection rate, respectively, by 12.8% and 11.7%. This shows that the optimization scheme has important significance in practical application, and can meet the high requirements of modern sea, land, and air operations to aviation airborne communication networks. [ABSTRACT FROM AUTHOR]

As one of the main candidates for future civil aviation communications systems, the L-band digital aeronautical communication system (L-DACS) is expected to achieve secure and reliable transmission. Due to the broadcasting nature of air–ground wireless links, the L-DACS has the risk of being intercepted by malicious eavesdroppers, which negatively affects aviation communication security. In addition, because the spectrum of the L-DACS overlaps with the aviation distance measuring equipment (DME), the pulse interference caused by the DME signal may lead to the wireless link being more fragile and susceptible to wiretapping. In this paper, with a focus on enhancing wireless transmission security, we propose a comprehensive physical layer security (PLS) method for the L-DACS. The key to the proposed PLS method is restraining the transmission of the eavesdropper by injecting artificial noise into the transmitted signal while improving the transmission of the legitimate receiver through the adoption of pulse interference mitigation. First, to characterize the L-DACS in the secure scene, we derive the signal-to-interference-plus-noise ratio (SINR) of the legitimate receiver and any potential eavesdropper by constructing equivalent noise. Next, from the perspective of the information theory, we derive the closed form of the secrecy capacity of the L-DACS by employing the proposed PLS methods with three kinds of nonlinear interference mitigation: including ideal pulse blanking, peak threshold-based pulse blanking, and peak threshold-based pulse clipping. Finally, we compare and analyze different ways to enhance the secrecy capacity of the proposed PLS method using various interference mitigation methods. [ABSTRACT FROM AUTHOR]

Automatic modulation classification is an important component in many modern aeronautical communication systems to achieve efficient spectrum usage in congested wireless environments and other communications systems applications. In recent years, numerous convolutional deep learning architectures have been proposed for automatically classifying the modulation used on observed signal bursts. However, a comprehensive analysis of these differing architectures and the importance of each design element has not been carried out. Thus, it is unclear what trade-offs the differing designs of these convolutional neural networks might have. In this research, we investigate numerous architectures for automatic modulation classification and perform a comprehensive ablation study to investigate the impacts of varying hyperparameters and design elements on automatic modulation classification accuracy. We show that a new state-of-the-art accuracy can be achieved using a subset of the studied design elements, particularly as applied to modulation classification over intercepted bursts of varying time duration. In particular, we show that a combination of dilated convolutions, statistics pooling, and squeeze-and-excitation units results in the strongest performing classifier achieving 98.9% peak accuracy and 63.7% overall accuracy on the RadioML 2018.01A dataset. We further investigate this best performer according to various other criteria, including short signal bursts of varying length, common misclassifications, and performance across differing modulation categories and modes. [ABSTRACT FROM AUTHOR]

Aviation is a multidisciplinary subject that has influenced human development over the last century. Learning about aviation exposes students to principles of flight, earth science, aeronautical engineering, language, aviation communication and airmanship. In higher education, many non-aviation undergraduates participate in aviation related activities to have a first glimpse of the aviation industry and equip themselves with basic concepts. This study aims to examine learning perception among 82 university students who have participated in a series of online aviation career exploration activities during the pandemic in Hong Kong and China. They participated in virtual visits and career talks led by aviation professionals, hands-on flight simulation activities and online discussion in an online lab setting. A mixed research method was employed with the use of a motivational survey, teachers' observation and semi-structured interviews to understand students' learning perceptions. This study found that flying laboratory activities could effectively motivate students to learn aviation and improve their aviation knowledge. This could promote students' aviation industry optimism, which may help the industry to recover in the post-pandemic world. This article offers recommendations for online engineering educators to use emerging technologies to teach aviation for future career preparation. [ABSTRACT FROM AUTHOR]

In collaborative combat operations, the challenges posed by communication adversities in aviation data links have become increasingly conspicuous. Ensuring the reliable connectivity of data links has thus emerged as a critical issue, particularly in light of growing interference effects on communication link outage. To address this challenge, this paper proposes a cooperative non-orthogonal multiple access (NOMA) technology that aims to enhance interference tolerance and strengthen stable communication capabilities in data links. To achieve these goals, an anti-interference collaborative NOMA system model applicable to aviation data links is established, and the anti-interference performance of collaborative NOMA technology is analyzed under Rice fading channel conditions. The analysis centers on the system's outage probability, for which a closed-form expression is derived. Numerical analysis methods are employed to calculate and solve the expression, while simulation experiments are conducted to analyze the effect of factors such as transmission power, cooperative forwarding power, interference power, communication distance, and allocation coefficients on the system's outage probability. The results show that the aviation data link system using a collaborative NOMA scheme has better anti-interference performance than a non-collaborative scheme, and adjusting the above parameters can effectively improve the system's stable communication performance. [ABSTRACT FROM AUTHOR]

Due to the rarity of female pilots, aviation communication is typically conducted in a single-gender environment. The role of gender in interactions during inflight emergencies has not yet been adequately explored. This single case analysis uses a qualitative approach based on conversation analytic transcripts to investigate how gender may be relevant either explicitly or implicitly in radio transmissions between flight crew and Air Traffic Control (ATC) personnel, as well as internal ATC phone interactions as participants work to handle an inflight emergency. This incident involved a female pilot and a male copilot, thus providing a naturally occurring rare event to explore the potential relevance of gender. The analysis shows that explicit references to gender are limited to occasional asymmetrical use of gendered address terms and gendered pronouns. Participants also used interactional formulations that--while not explicitly gendered--have been associated in previous research with gender differences in interaction, for example, the use of indirect forms of requests or complaints, actions that imply inferences about the emotional state of participants, or possible confusion over the identity of the pilot given the transitions between male and female sounding voices speaking on behalf of the plane. The findings are discussed in terms of implications for how gender differences can impact aviation communication during emergency incidents. [ABSTRACT FROM AUTHOR]

To place communication in context against other maintenance error promoting contributory factors and identify whether communication issues were written or verbal, a semi-structured interview schedule was used to ask 40 aircraft maintenance personnel what goes wrong when maintaining aircraft. Participants described 746 examples of contributory factors and undesired outcomes which were categorized using Dupont's "dirty dozen." 147 of the 746 descriptions were communication factors, of which 99 were verbal, 34 were written and 14 were general. Of 34 verbal and 19 written task miscommunication examples, 22 verbal and 10 written were accompanied by descriptions of undesired outcomes. The results suggest that commercial aircraft maintainers consider verbal and written communication as more important than other contributory factors. [ABSTRACT FROM AUTHOR]

Purpose: Ineffective communication consequences can be life-threatening and drastic. Communication misunderstandings are frequently reported in incidents, accidents and occurrences. This research paper aims to evaluate operator communication load in highly automated systems; distinguish and highlight the communication error factors during flight operations from different perspectives; and provide suggestions to operators to decrease the rate of misunderstandings in aviation communication. Design/methodology/approach: This study is based on a questionnaire that investigated the critical communication load, including aviation training, standard phraseology, operators' native language and cultural background. In addition to the effect of using controller–pilot data link communications will be discussed widely. In this research, 110 responses were obtained from pilots and air traffic controller (ATCOs) that vary in 44 countries; approximately 20% were ATCOs, and 75% were pilots. Findings: This study was designed to assess the level of aviation operators communication load in highly automated systems, identify and illustrate the factors that contribute to communication errors during flight operations from multiple viewpoints, and offer recommendations to operators to minimize the rate of misunderstandings in aviation communication. Originality/value: This research deals with evaluating the operators' communication load, which is crucial for the air traffic safety and efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Having error-free communication in air-to-ground communication is somewhat nonsensical in real-life conditions. Multiple factors, external or internal, inevitably cause miscommunication or misunderstanding. During unprecedented situations, the ability to adapt and language competency becomes a significant factor in ensuring that communication between pilots and air traffic controllers can succeed. Aviation English falls under English for Specific Purposes and acts as a lingua franca for aviation communication. Thus far, language training is still inadequate to prepare pilots and air traffic controllers during emergencies or non-routine situations. The open-ended survey was conducted before the first development phase of the aviation communication competence framework. The rationale of this survey is to understand the need and perception of aviation language among pilots and air traffic controllers. The findings suggest that although they feel confident using aviation English in radiotelephony, most agree that it is imperative to have language training to improve aviation communication safety and standardise aviation phraseology and language. The findings also suggest that fundamental English language proficiency and non-standard phraseology use reduce efficiency in aviation communication. Furthermore, cultural and linguistic diversity among pilots and air traffic controllers creates misunderstandings and non-understanding in interactions. These findings suggest that aviation language development and training can be improved by diligent monitoring and evaluating the current needs of pilots and air traffic controllers. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method to improve the performance and reduce the implementation design complexity of the angular domain cyclostationary feature detection (CFD). This method implements Orthogonal Frequency Division Multiplexing (OFDM) signal detection for cognitive radio applications. The originality of this work is based on using a selective sampling process for the OFDM signal detection by using only samples related to the cyclic prefix (CP). Using only the first N C P (CP length) angles of the angular domain cyclic autocorrelation function and eliminating the remaining angles has significantly improved the detector sensitivity. Results from Matlab simulations revealed that the proposed method reaches a detection probability of 100% at an SNR (signal-to-noise ratio) equal to − 16 dB in the case of an additive white Gaussian noise (AWGN) channel. Moreover, the proposed method outperforms the other CFD methods with a performance range up to 5 dB. The proposed algorithm is coded using the VHDL language and implemented with the minimum of counters and comparators on Field-programmable gate array (FPGA) platform without using multipliers and DSP blocks. The proposed design requires a lesser power, logic and memory bits by 5.95, 60.96 and 87.5%, respectively, compared to the conventional angular domain CFD design. The proposed hardware architecture can be more efficient for spectrum sensing in many communication systems, such as LTE-Advanced and the L-band Digital Aeronautical Communication System (LDACS). • Angular Domain cyclostationary feature detection of OFDM signals. • A new selective sampling process is adopted to improve the detector's sensitivity. • An optimised design of the proposed method is delivered and hardware prototyped on an FPGA platform. [ABSTRACT FROM AUTHOR]

Air travel is growing at an alarming rate. However, according to the latest research report by Eurocontrol on European aviation, the growth of air traffic will be limited by the available spectrum resources. As one of the means to provide air/ground (A/G) broadband communication, the L-band digital aeronautical communication system (LDACS) is becoming the preferred model for final deployment and has received continuous attention. Based on various spectrum measurement studies, the international civil aviation organization (ICAO) has identified multiple 1 MHz vacant bands between adjacent distance measuring equipment (DME) signals for LDACS. In order to improve spectrum efficiency, the concept of dynamic spectrum access (DSA) can be applied to the LDACS, which requires the use of spectrum sensing methods to detect the spectrum holes of DME users. In this paper, an adaptive threshold energy detection spectrum sensing method is proposed based on the characteristics of DME pulse signals. Firstly, the energy of the received signal is estimated to construct the detection statistics, and the equations of detection probability and false alarm probability are established. Secondly, the adaptive threshold is calculated using the maximum likelihood decision criterion under the assumption of a constant probability of false alarm. Thirdly, the detection statistic is compared to the adaptive threshold to determine the spectrum occupancy state in the decision-making stage. Finally, the result is transmitted back to the transmitter for the best spectrum resource allocation. According to the simulation analysis, the adaptive threshold energy detection-based sensing method outperforms the energy-difference detection method under low signal-to-noise ratio (SNR) conditions. Meanwhile, it has superior adaptability since the adaptive threshold can be adaptively changed according to the channel. [ABSTRACT FROM AUTHOR]

In 2016, the US Forest Service initiated small-group safety discussions among members of its wildland firefighting organisation. Known as the Life First National Engagement Sessions, the discussions presented an opportunity for wildland firefighters to address systemic and cultural dysfunctions in the wildland fire system. The Life First initiative included a post-engagement survey in which more than 2600 Forest Service employees provided open-ended feedback. In that qualitative subset of results, survey respondents described four main situations in which wildland firefighters commonly accepted unnecessary exposure to risk, related to driving, mop up, aviation and communication. Findings reveal how firefighters experienced social, political and economic pressures upon and within the wildland fire system. They shared that these perceived pressures and their mission-oriented work culture interacted, transforming otherwise unremarkable work operations into situations of unnecessary exposure to risk. Organisational studies can unearth the values of everyday work cultures. This application of the social science of wildland firefighting discusses unnecessary risk in normal operations. Perceived internal and external organisational pressures interact with mission-oriented work cultures, creating for employees an unnecessary exposure to risk. Forest Service photograph by Kari Greer, taken on 24 August 2016. [ABSTRACT FROM AUTHOR]

Small-Signal Darlington pair amplifiers with MOS-BJT-MOS hybrid unit under triple transistor topology are demonstrated using PSpice and GPDK 180nm technology in Cadence Virtuoso and Spectre tool. The first circuit under Cadence tool produces moderate voltage gain (5.156), high current gain (2165.6), wide bandwidth (15.8866 GHz), high power gain (40.4789 dB-Watt), low power consumption (556.556 mW) with low THD (11.85E-6 %) and could be used in Radar, TV and wireless communication receivers where as the second circuit with PSpice user defined model generates high voltage gain (933.235), very high current gain (44207), wide bandwidth (16.275 MHz), high power gain (76.1548 dB-Watt), low power consumption (71.6mW) and low THD (1.18%), thus it may be used in AM radio broadcast, marine and aeronautical communications. Respective amplifiers are compared with previously announced commercial transistor-based circuit which shows very promising result in terms of voltage gain, current gain, and power consumption. Proposed amplifiers are also physically verified in the Cadence using virtuoso layout editor tool which shows that it covers a small area of 80.0124 μm2 with a dimension of 8.97μm x 8. 92μm. Small-signal AC analysis, different configurations of the proposed amplifier, variation of the voltage gain with respect to different circuit components are amongst the few studies attempted in the present paper. [ABSTRACT FROM AUTHOR]

With the development of global air transport， air traffic services， including air traffic control， aeronautical operational control，etc， have entailed higher performance of aviation communication systems. As one of the new generation aviation communication system schemes， L‑band digital aeronautical communication system （L‑DACS） could achieve a better data transmission rate， spectrum utilization efficiency and capacity， solving scarcity of spectrum resources. This paper summarizes L‑DACS’s state‑of‑the‑art progresses and studies， specifically its technology evolution and standardization development. Then， a draft of layered system framework is introduced， covering network， datalink and physics levels. Finally， challenges that L‑DACS faces and its corresponding developing proposals are given. This review provides a reference for the research of aviation broadband communication. [ABSTRACT FROM AUTHOR]

Due to the exponential growth in the aviation industry, the number of non-native speaker pilots and air traffic controllers has significantly increased. Naturally, the interaction has become more challenging since the communication shifted to intercultural communication within a lingua franca setting. This study identifies and discusses the repair and accommodation strategies pilots and air traffic controllers use in their routine in-flight communication. The corpus consists of 30 hours of actual pilot-controller audio communication collected from the Malaysian airspace. Audio data collected from three frequencies (Alpha, Bravo and Charlie) were analysed using the conversation analysis method. The findings extend existing knowledge on miscommunications in pilotcontroller discourse. The study found that in most instances, pilots and controllers made conscious efforts to repair the various types of miscommunications that took place. The findings also show that communication errors and misunderstandings are commonly caused by cultural differences and inadequate language competency amongst the pilots and controllers. The paper concludes by suggesting that repair strategies and intercultural communication competence should be integrated within aviation communication training modules to improve pilot and controller communication strategies in intercultural settings. [ABSTRACT FROM AUTHOR]

Although effective risk management is highly dependent on risk perception and communication, limited attention has been given to the influence and consideration of these two constructs and their factors in the aviation industry. This research aimed to map practices and perspectives of safety investigators regarding risk perception and communication in aviation and reveal respective influential parameters. The interviews with ten experienced safety investigators revealed that they consider and search risk perception and communication factors but with a divergent emphasis. Investigators acknowledged the effects of emotional and cognitive biases as well as the role of context when examining risk perception and communication factors and attributed the shaping of the latter to organisational practices, mainly training, supervisory and cultural aspects. Overall, the findings of this study suggest investigation methods could be enriched with a systematic approach to examining the role of risk perception and communication and considering their shaping factors while also providing directions for abating subjectivity when addressing these two constructs. This could be facilitated by developing a common reference framework for risk perception and communication and be accompanied by support from specialists and training in the management of investigators' heuristics. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Present-day technologies used in SHM (Structural Health Monitoring) systems in many implementations are based on wireless sensor networks (WSN). In the context of the continuous development of these systems, the costs of the elements that form the monitoring system are decreasing. In this situation, the challenge is to select the optimal number of sensors and the network architecture, depending on the wireless system's other parameters and requirements. It is a challenging task for WSN to provide scalability to cover a large area, fault tolerance, transmission reliability, and energy efficiency when no events are detected. In this article, fundamental issues concerning wireless communication in structural health monitoring systems (SHM) in the context of non-destructive testing sensors (NDT) were presented. Wireless technology developments in several crucial areas were also presented, and these include engineering facilities such as aviation and wind turbine systems as well as bridges and associated engineering facilities. [ABSTRACT FROM AUTHOR]

Establishing an instantaneous channel propagation model in aircraft engineering simulators is important for aircraft systems development. This article investigates an instantaneous channel propagation modeling scheme with compressed sensing (CS) recovery and electromagnetic (EM) interpolation for aeronautical communications systems to reduce the cost of flight experiments. Specifically, the system architecture introduces the proposed modeling process of the instantaneous aeronautical channel. The mathematical models are analyzed to show the sparsity of the aeronautical channel with a limited scattering environment. The channel modeling algorithm is detailed by explaining the CS algorithm and the EM interpolation scheme. The experimental results show the effectiveness of the proposed method. Most recovery relative errors between the recovering channel model and the real sampled channel responses are lower than 0.1, i.e., −10 dB. More than 75% of the sampling points can be reduced by the proposed method compared with the real flight experiments. Moreover, the proposed single-input-single-output (SISO) approach can also be applied in the potential aeronautical communications systems with multiple-input-multiple-output (MIMO) transmission. [ABSTRACT FROM AUTHOR]

The L-band digital aeronautical communications system (LDACS) is a key enabler of the new air traffic services and operational concepts necessary for the modernization of the air traffic management (ATM). After its initial design, compatibility tests with legacy L-band systems, and functional demonstrations in the laboratory, the system is currently undergoing the standardization process of the International Civil Aviation Organization (ICAO). However, LDACS has not been demonstrated in flight yet. In this article, we present the first in-flight demonstration of LDACS, which took place in March and April 2019 in southern Germany and included four LDACS ground stations and one LDACS airborne station. We detail the experimental setup of the implemented LDACS ground and airborne stations together with the flight routes, the conducted experiments, and the frequency planning to ensure compatibility with legacy systems. In addition, we describe the demonstrated ATM applications and the security measures used to protect them. Based on the obtained measurement results, we evaluate the LDACS in-flight communication performance for the first time, including the achieved communication range, the measured end-to-end message latency, and the LDACS capability to provide quality of service by effectively prioritizing safety-relevant data traffic. Furthermore, we use the in-flight received signal power to assess the applicability of a theoretical path loss model. These flight trials contribute to the final steps in the development of LDACS by providing its in-flight communication performance and by demonstrating: first, its correct functionality in a realistic environment; second, its capability of supporting ATM applications and the advanced security measures that can be used to protect them; and third, its spectrum compatibility with legacy systems. We conclude that LDACS is ready to support ATM operations and that LDACS frequency planning can safeguard legacy systems successfully. [ABSTRACT FROM AUTHOR]

This paper presents the results of the research in the field of anti-collision systems for small civil aircraft, which are not dependent on secondary radars and satellite navigation systems. The aviation communication network was used to design the anti-collision system. The simulation results manifested that the anti-collision system precision depended on the errors of synchronization of the aviation communication network. The precision of the anti-collision system is also influenced by the errors of the coordinates of individual aviation communication network users, based on which the system identifies its own position. The results of the simulation show that the dispersion of the positioning error σ2∆P by the ACS system varied in the range of 1.94 m2 to 503.23 m2. The simulation results confirm that the designed anti-collision system is operational in establishing its position against other FOs, with the distance from the given FOs being 50.0 km maximum. The main contribution of this paper are derived algorithms for the operation of an anti-collision system for small civil aircraft, in addition to the design of movement trajectory models of five flying objects which operate within the aviation communication network. The advantage of the anti-collision system is that it is independent of satnav systems and secondary radars. A significant advantage is the low cost of this system. [ABSTRACT FROM AUTHOR]

Having proficiency in the standard aviation phraseology specified by International Civil Aviation Organization (ICAO) is of great importance for prospective pilots in communication with air traffic controllers and other pilots. The ambiguity in the standard phraseology could be a disaster for the flight crews. Serious thought, thus, has been given to the policy of improving precise communication in aviation. However, it remains unclear whether the serious game-based flight simulations can enhance the vocabulary intake of the learners who invest the majority of their time in studying the standard aviation phraseology. There is also a dearth of research pertaining to the association between serious gaming and aviation phraseology. The advancement of technology has exponentially expanded digital games and therefore began to be widely used in education. The current study thus sets out to investigate the effect of a serious simulation game X-Plane 11 offering an invaluable learning experience on aviation vocabulary acquisition. This investigation takes the form of quasi-experimental mixed-method research by retrieving convenience sampling (15 subjects in the experimental group, 15 subjects in the control group). The findings indicated that there was strong evidence of the positive effects of serious gaming on the learners' outcomes. Following the integration of the serious game, a significant increase in the medium effect size in the experimental group was recorded. This finding was also echoed by the majority of the interviewees who unanimously emphasized that the game was beneficial and motivating for language learning despite the minority challenges triggered by the level of language, hardware, and software types. [ABSTRACT FROM AUTHOR]

The L-Band Digital Aeronautical Communications System (LDACS) 1 is an alternative to the current Very High Frequency (VHF) technology which meets the needs of upcoming demands. LDACS1, an Orthogonal Frequency Division Multiplexing (OFDM), operates in the L-Band between 960 and 1167 MHz frequencies installed in the middle of two Distance Measuring Equipment (DME) channels with 500 kHz spectral gap. In this paper--LDACS1 OFDM and LDACS1 2 x 2 Multiple Input Multiple Output (MIMO) are designed and simulated without any interference. The DME interference is introduced only to the LDACS1 OFDM, and significant degradation in the performance is observed. The pulse blanking technique helps in lowering the interference in the LDACS1 OFDM system, resulting in a performance close to the performance in the interference-free case. The Bit Error Rate (BER) performances for the conditions with and without interference and pulse blanking are compared. An improvement in the BER performance is seen with respect to design of LDACS1 2 x 2 MIMO system. [ABSTRACT FROM AUTHOR]

Adaptive radio techniques have been extensively studied over the past two decades. In this paper, we investigate an adaptive algorithm to attain additive white Gaussian noise (AWGN) performance in non-white channels, using multicarrier communications such as OFDM and filter-bank multicarrier (FBMC). The non-white channel can be from non-white noise, or more commonly, interference. Our proposed algorithm: spectral shaping (SS), follows a simple optimization problem to find what we term reliable subcarriers, and then per subcarrier power allocations are made in order to attain the AWGN channel bit error ratio (BER). Subcarriers that experience high interference are deactivated or chosen as guard subcarriers. After describing our analysis, we show some simulation results in two non-white interference signal examples: the Gaussian pulse shaped high-power distance measuring equipment (DME) and a classical rectangular-pulse signal. The DME example is pertinent for currently proposed aeronautical communication systems, where new multicarrier techniques, e.g., the L-band digital Aeronautical communication systems (LDACS) have been designed as an inlay approach between the high-power DME channels in L-band. Our results show that in high DME power interferences, using this adaptive technique can improve the overall reliability and attain AWGN BER performance in AWGN channel. We provide power spectral density (PSD) results to compare OFDM and FBMC based spectra when our SS algorithm is applied. Also, we provide BER vs. bit energy to noise density ratio (Eb/N0) results in the AWGN, as well as more realistic aeronautical channels to compare SS system performance. Our results show that in the presence of high power DME interference, using this adaptive technique can improve the overall reliability and enable us to attain non-interference BER performance in realistic aeronautical channels. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this research is to investigate the pragmatic failure and other language-related risks between pilots and air traffic controllers in intercultural aviation communication. The paper attempts to provide recommendations for the minimization of these risks, thereby improving aviation safety by reducing the rate of aviation incidents and accidents. Pragmatic failure refers to the miscomprehension of intended pragmatic meaning. As opposed to semantic meaning, it depends on the context and is highly influenced by culture. Design/methodology/approach: The risk of pragmatic failure in aviation is presented hypothetically, and examples of language-related communication failure in air-to-ground communication between pilots and air traffic controllers (ATCOs) involving language are examined, including an example involving pragmatic failure. A questionnaire has been developed to survey pilots and ATCOs who communicate over radiotelephony. Results from 212 respondents are presented and conclusions are drawn. Findings: The authors propose, based on linguistic theory and the results of this survey, that native English-speaking aviation operators gain more familiarity with the inner workings of the English language, in particular regarding the difference between semantic and pragmatic meaning. They benefit from this awareness whenever communicating with people of other cultures to develop the valuable skill of focusing on semantic meaning while avoiding adding pragmatic meaning. This minimizes the potential of misunderstanding when an emergency arises that cannot be dealt with through the International Civil Aviation Organization standard phraseology and when the listener of this message is someone from a different culture. Practical implications: Language and communication are the main tools that play a vital role in reducing the rate of aircraft incidents and accidents. In aviation, pilots and ATCOs are neither in face-to-face contact nor have a video speech interface between them while communicating with each other. Their communications are conducted entirely through radio messages using a specialized language designed to make communication as accurate and efficient as possible. This study, therefore, is important in terms of investigating the risks of pragmatic failure and of language errors in general between pilots and air traffic controllers. This research will be a useful guide for designing training for operators (pilots and ATCOs) as well. Originality/value: The main focus of the study is to investigate reasons for pragmatic failure and other language-related causes of misunderstanding between pilots and air traffic controllers over air-to-ground communication. To illustrate these roles, a questionnaire has been developed for pilots and ATCOs who communicate over aeronautical radiotelephony and examples of aircraft accidents were given. [ABSTRACT FROM AUTHOR]

In view of the problem of the distance measure equipment (DME) signal interferes with orthogonal frequency-division multiplexing (OFDM) receiver for L-band digital aeronautical communication system 1 (L-DACS1), a DME interference suppression method based on block sparse Bayesian learning-the bound optimization (BSBL-BO) algorithm is proposed. Firstly, considering that the empty subcarriers of OFDM receiver never transmit useful signals, the compressed sensing model for DME pulse interference signal is established. Then the DME pulse interference signal is reconstructed based on the BSBL-BO algorithm. Finally, the reconstructed DME pulse interference is eliminated in the time domain. The simulation results show that this method has higher reconstruction accuracy and faster operation speed than the existing pulse interference suppression methods, which can further reduce the bit error rate of OFDM receiver and improve the trans mission performance of forward link in L-DACS1 system significantly. [ABSTRACT FROM AUTHOR]

Currently experienced the dawn of the Aviation 4.0 era is transforming the contemporary technological environment, throughout the whole aeronautical industry, by creating cyber-physical systems. Following the evolutionary path, incorporating advanced automated and first autonomy systems, the applications involved are becoming increasingly data- oriented. The need for progressive data analytics, massive adoption and operation of IoT devices, delivering advanced monitoring and machine learning opportunities, building the core structure for artificial intelligence, will put a significant pressure on data communication and connectivity itself. In the near future, the problems may especially arise in datalink used in civil aviation. This research paper briefly studies the contemporary systems used for datalink, determines dominant aspects of Aviation 4.0 and their overall impact on the performance requirements of the data communications network, and proposes the possible solution to the problematics, with newly emerging LEO satellite mega-constellations providing Internet connectivity. The conclusion of this paper highlights the requirements for future data communication systems and determines whether the existing and proposed datalink subnetwork technologies are capable of meeting the demands established by Aviation 4.0. [ABSTRACT FROM AUTHOR]

The aim of the paper is to analyse a terminological mechanism applied in choosing English words and phrases which are the basis for professional communication between airport aircraft mechanics of various nationalities. Correctly applied terminology facilitates successful communication and can contribute to reducing incidents arising from errors made during aircraft pre-flight preparation. Aircraft mechanics communicate not only by means of specialised terms and acronyms, but also by AECMA/ASD1 standardised Simplified Technical English for technical documentation purposes. Due to frequent text comprehension problems, common specific words have been selected according to the rule "one word - one meaning." Furthermore, English grammar has been simplified for successful international communication between aircraft mechanics. Thus, a specific communication tool has been created and is currently in global use, which indirectly contributes to flight safety. The author presents common trends applied in the process of terms selection in the working environment. She also emphasises the necessity of using clear and concise terminology in aviation communication. The author's observations can support aircraft mechanics' language training, and terminological as well as translation work. The article familiarises the reader with some key concepts of aircraft maintenance terminology. [ABSTRACT FROM AUTHOR]

English language proficiency is a vital requirement for air-to-ground communication for aviation specialists. A special attention should be paid to developing speaking skills of future pilots, air traffic controllers and engineers. Our research has shown that future aviation specialists come across certain challenges in the process of communication in English: insufficient aviation knowledge to give an opinion, low motivation to speak, poor grammatical skills and insufficient knowledge of vocabulary items, uneven participation in discussions, and fear of making mistakes. To overcome these challenges some recommendations were formulated for teachers to follow. The problem-solving activities were chosen and designed to enhance students’ speaking skills. They include value-clarification tasks, discussions, role-plays, information-gap activities, describing pictures, and discussing videos. This research aims to define the impact of applying these problem-solving activities on developing students’ speaking skills. 120 second year students in aviation specialties took part in this experiment. They were divided into a control and an experimental group of equal numbers. In both groups, the teachers taught the same Aviation English content which corresponded to the syllabus. In addition, in the experimental group the teacher implemented the problem-solving activities, which contributed significantly to the development of future aviation specialists’ speaking skills. [ABSTRACT FROM AUTHOR]

Summary: Air‐to‐ground (A/G) communications have been transferred from the congested very high frequency (VHF) band to occupy the guard bands between adjacent distance measurement equipment (DME) navigation channels within the L‐Band. However, the inlayed channels, called L‐band digital aeronautical communication system (LDACS) channels, experience severe interference with the coexisting DME channels. In this paper, a DME interference detection and mitigation technique is proposed to improve the performance of the LDACS in the presence of DME interference. The DME energy detector based on Neyman–Pearson test is proposed, which has more advantages than the other techniques due to its noncoherent nature and simplicity. Furthermore, the proposed DME detection technique is performed by using an adaptive threshold to achieve the best trade‐off between the DME signal detection and false alarm. The proposed DME interference mitigation technique relies on the proposed concept of nested RF upconversion, where the in‐phase and the quadrature components of an LDACS signal are forwarded to a code division multiple access (CDMA) block in which they are transmitted only over the quadrature branch once DME interfering signal is detected. In this work, the closed form expression for the probability of DME detection, false alarm, and the detection error rate are derived. Simulation is performed, and the results show that the proposed technique provides improvement in the probability of DME detection and the detection error rate compared to the previous work. Also, simulation results shows that the proposed technique provides lower bit error rate and less complexity compared to the previous work. [ABSTRACT FROM AUTHOR]

Maximizing the coherent processing interval (CPI) is crucial when performing passive radar detection on weak signal reflections. In practice, however, the CPI is limited by the target movement. In this work, the extent of the range and Doppler migration effects occurring when using a long CPI to integrate the returns from an $L$ -band digital aeronautical communication system (LDACS) based passive radar is studied. In particular, our simulations underline the extensive Doppler migration effect that arises even for nonaccelerating targets. To this end, the Keystone transform and fractional Fourier transform techniques are combined with the standard passive radar processing to enable the compensation of both range and Doppler migration effects. This nonmodel-based approach is, however, shown to have limitations, in particular for low signal-to-noise ratios and/or multitarget scenarios. To address these shortcomings, a novel model-based framework that allows to perform joint target detection and parameter estimation is developed. For this, a super-resolution sparse Bayesian learning approach is employed. This technique uses a multitarget observation model, which accurately accounts for the underlying range and Doppler migration effects and provides super-resolution estimation capabilities. This is particularly advantageous in the LDACS case since the narrow bandwidth generally limits the separation of closely spaced targets. The simulation experiments demonstrate the effectiveness of the algorithm and the advantages it provides when compared to the standard migration compensation approach. [ABSTRACT FROM AUTHOR]