Air Traffic Management and Systems III

In this chapter, an overview of the fifth ENRI International Workshop on ATM/CNS (EIWAC2017) is provided, together with summaries of presentations at keynote sessions and special speeches. This chapter also explains the approach of the Electronic Navigation Research Institute toward the organization of EIWAC. In this workshop, various aspects of air traffic management (ATM) and its enablers in the fields of communication, navigation, and surveillance (CNS) were discussed. EIWAC2017 was held in Nakano, Tokyo, from November 14 to 16, 2017.

The future airspace has to provide a reliable infrastructure and operational concept to ensure efficient and safe operations considering both flight-centric operations and the integration of new entrants. We propose an approach for a dynamic sectorization to manage the air traffic demand and flow appropriately. Our dynamic sectorization results in enhancements of the current operational structure (less deviation in controller task load) and leads to a significantly lower controller task load for the newly created airspace. Since future 4D trajectory management demands an efficient consideration of operational (e.g., temporally restricted areas), ecological (e.g., contrail prevention), and economic (e.g., functional airspace blocks) constraints, our dynamic sectorization method contributes to the highly flexible use of current and future airspace. In this paper, we provide an overview of several use cases and describe the working principle of our approach: fuzzy clustering of air traffic, Voronoi diagram for initial structures, and evolutionary algorithms for optimization.

Notably, in engineering and behavioral sciences, the topic of resilience is being investigated broadly quantitatively in technical systems like infrastructure or public transportation and qualitatively with respect to social and organizational aspects. Especially with regard to disturbances and crises in complex socio-technical systems, human operators play a pivotal role in ensuring the continuation of operations by adapting to the situation. An integrated framework for quantitative assessment as well as behavioral aspects in a socio-technical system is therefore essential to measure resilience and to compare different design approaches. The combination of quantitative and qualitative approaches is presented in this paper. In the wake of a crisis often not only the system itself is affected but also interdependent systems. The resilience of those combined systems is the subject of this conceptual paper. Two objectives are pursued. First, the creation of generic resilience management guidelines which are subsequently translated into operating procedures, strategies, and practices in order to support individuals, systems, and organizations in the face of crisis and to validate their cross-domain applicability. The second objective of the paper is to contribute to closing the gap between formal descriptions of resilience in technical systems and the representation of the influence of the human operators. This is done by following an approach that combines serious gaming exercises of different scenarios, expert judgment and a simplified simulation of the involved systems which provides a quantitative assessment of resilience. The ongoing work described in this paper is being carried out within the scope of the DARWIN project which has received funding by Horizon 2020. Preliminary results of the project that address the creation of resilience management guidelines will be presented.

In this paper, the problem of aircraft trajectories representation and analysis is addressed. In many operational situations, there is a need to have a value expressing how trajectories are close to each other. Some measures have been previously defined, mainly for trajectory prediction applications, all of them being based on distance computations at given positions in space and time. The approach presented here is to consider the trajectory as a whole object belonging to a functional space and to perform all computations in this space. An efficient algorithm for computing mathematical distance between trajectories is then presented and applied to the major flows extraction in the French airspace.

In this paper we investigate the application of generalized polynomial chaos (gPC) for optimal control based aircraft safety assessment with parameter uncertainties. The approach is based on the formulation of an appropriate optimal control problem to obtain worst case inputs. The criterion to be assessed is introduced in the cost function and the numerical solution is obtained using direct optimal control methods. In this context, we consider the case where the parameter distribution is unknown and assume a truncated uniform distribution with truncation values to be determined. The approach can be summarized as follows: First an optimization assisted bisection search algorithm is performed. This algorithm yields regions of a defined size in which a violation of the criterion occurs. In order to obtain a local explicit representation of the worst-case solution, we approximate this solution in the parameter space using a spectral representation based on gPC. This representation is then used to determine the worst case truncation limits of the uniform distribution and to estimate the exceedance probability for the criterion under investigation. The application is illustrated using a F-16 short period model with model reference adaptive controller. In this example, we estimate the exceedance probability for the maximum tracking error in the angle of attack for worst case reference command inputs and plant uncertainties in pitch damping, pitch stiffness, and control effectiveness.

The existence of significant uncertainties in the models and systems required for trajectory prediction represents a major challenge for the Trajectory-Based Operations concept. Weather can be considered as one of the most relevant sources of uncertainty. Understanding and managing the impact of these uncertainties are necessary in order to increase the predictability of the ATM system. We present preliminary results on robust trajectory planning in which weather is assumed to be the unique source of uncertainty. State-of-the-art probabilistic forecasts from Ensemble Prediction Systems are employed to characterize uncertainty in the wind and potential convective areas. A robust optimal control methodology to produce efficient and predictable trajectories in the presence of these uncertainties is presented. A set of Pareto-optimal trajectories is obtained for different preferences between predictability, convective risk, and average efficiency.

In this study, we focus on the problem of locating optimally dynamic military areas with the aim of minimizing the number of civil flight trajectories potentially impacted by the military activity, and the distance between the military area and the military base. We model the military areas by 2D geometry shapes with a vertical extension associated with given flight levels during the temporary area-activation time window. We propose a mathematical formulation of this problem as a constrained-optimization problem. We then introduce a global-optimization methodology based on a simulated annealing algorithm featuring tailored neighborhood-search strategies and an astute computational evaluation of the otherwise costly objective function. This is applied to 1-day of French traffic involving 8,836 civil flights. The results show that the proposed method is efficient to locate the military area that is nearest to the military base, while minimizing the potential impact on civil flight trajectories.

In order to achieve safe, secure, efficient, and environmentally sustainable air traffic management at global, regional and local levels, a collaborative environment for system-wide flight and flow information exchange is required. Therefore, the new provisions to enable a richer set of information exchange prior to departure between different aviation stakeholders with new flight planning and filing capabilities has been structured by the International Civil Aviation Organization (ICAO). This collaborative information exchange will enable a common operational picture for all related stakeholders in order to improve strategic planning. However, with the different conditions, it is difficult for all air traffic management service providers to transform from the current operation to the new operation and not all airspace users will adopt the changes at the same time. To validate the impact of changes for potential implementation of new provisions, the project of international validation has been conducted. In this paper, the observations and analysis of validation exercises consisting of Tabletop exercises and Lab exercises related to the regional implementation will be reported. Moreover, the operational processes, procedures, and automation changes required for new provisions implementation between related aviation stakeholders are clarified. Finally, the problems and challenges for constructing the collaborative operating environment to include interactions of related stakeholders using data, systems, and services through a system-wide information management environment are discussed.

A ground-based augmentation system (GBAS) is a navigation system using global navigation satellite system (GNSS) that enables precision approaches and landing for aircraft. In May 2010, the International Civil Aviation Organization (ICAO) Navigation Systems Panel (NSP) working group completed development baseline standards and recommended practices (SARPs) for GBAS ground subsystems to support GBAS approach service type D (GAST-D), which refers to Category III precision approach services using the single-frequency L1-C/A signal. The Electronic Navigation Research Institute (ENRI) developed a prototype of the GAST-D ground subsystem to operationally validate the development baseline SARPs. Owing to the fact that ionospheric delays with large spatial gradients represent one of the most significant risks to the integrity of the GAST-D operation, the system was installed in a low magnetic latitude region where plasma bubble causes steep spatial gradients in the ionospheric delay. Preliminary results were reported to the NSP working group before the development baseline SARPs were approved in December 2016 with an expectation that they would go into effect in 2018. Here, we report the development of a prototype for a GAST-D ground subsystem to validate the development baseline SARPs and preliminarily evaluate the system’s performance.

Ground-based augmentation system (GBAS) interoperability trials were conducted in Ishigaki, Japan in June 2016. The interoperability of different implementations of GBAS airborne equipment/software including the TriPos from TU Braunschweig, a software from ENRI, and the Pegasus software developed by EUROCONTROL were tested with an experimental GAST-D ground prototype developed by ENRI and manufactured by NEC. Some differences were observed in protection levels, likely because of differences in the software tools’ satellite selection strategies. Even so, the position solutions and course deviations were in good agreement between the different implementations, so that interoperability was demonstrated successfully.

This paper summarizes GBAS tests conducted by the Technische Universität Braunschweig (TUBS), the Electronic Navigation Research Institute (ENRI) and European Organisation for the Safety of Air Navigation (EUROCONTROL) in the frame of the Single European Sky ATM Research Programme (SESAR, subproject 15.3.7). For these tests, an experimental GBAS ground facility transmitted VDB data for current and future approach services. On the one hand, this paper summarizes the efforts to ensure backward compatibility and interoperability. To this end, existing GBAS hardware receivers were tested and compared with different software solutions. These tests confirmed that the proposed VDB formatting does not interfere with existing GBAS implementations. On the other hand, these tests were intended to support the development of future Multi-Constellation and Multi-Frequency GBAS services. GNSS data recorded at the ground reference receivers and the research aircraft D-IBUF was used to calculate an experimental ionosphere-free GBAS solution not threatened by ionospheric gradients. This paper presents initial results for the proposed GAST-F service, demonstrating that (despite the low number of L1 and L5 capable GNSS satellites currently available) this kind of processing could be a candidate for a future MC/MF CAT-II/III GBAS service.

Automatic Dependent Surveillance-Broadcast (ADS-B) is one of the key available technologies for aircraft surveillance. ADS-B provides high accurate GNSS positions with high update rate for air traffic control and airline operations. This feature will improve the safety and efficiency of air traffic operations. However, ADS-B user cannot benefit from the accuracy capability because the ADS-B message does not include information of GNSS measured time and because of the latency between the GNSS measured time and ADS-B message arrival time. In this paper, we propose a technique to estimate the variable element of ADS-B latency. Then, the proposed technique is applied to real data obtained by ENRI experimental system. The results of the estimations are presented in support of performance assessment.

Automatic-dependent surveillance-broadcast (ADS-B) receivers are vulnerable to jamming and spoofing attacks. Air traffic management is expected to heavily rely on ADS-B in the future so it is important to provide protection against these attacks. One promising solution is array signal processing. Jamming signals can be suppressed by beamforming and ADS-B positions can be verified by comparing them to the measured angles of arrival (AoAs). Many studies have been done on this topic but they generally consider either jamming or spoofing. However, in a real environment, anti-jamming and anti-spoofing functions must be provided together. It is important to understand the performance when these two functions are implemented simultaneously in order to guide future research and development strategies and implementation plans. Thus, we conducted an experimental evaluation of anti-jamming and anti-spoofing functions. For jamming protection, a power-inversion beamformer was used to suppress the jamming signal. For spoofing protection, a Capon’s beamformer was used to measure the AoA. The array used was a uniform linear array of four elements. The experiments were conducted in an anechoic chamber using a four-channel oscilloscope and the signal processing was conducted offline. The results of the anti-jamming experiment showed that the jammed signals were successfully recovered and the signal-to-jamming-plus-noise (SJN) ratio was increased to above the decodable level. The effects of various parameters on the overall performance and the lower bound performance were also investigated. Moreover, the anti-spoofing experiment showed that the AoA of the ADS-B signal could be measured successfully. The AoA accuracy was evaluated in terms of the standard deviation, which was further converted into the probability of spoofing detection. These findings will be important in the implementation of effective infrastructure to ensure safe air travel.

This paper proposes an unsupervised algorithm for airport runway area detection based on super-pixel PolSAR image classification. First, the simple linear iterative clustering (SLIC) algorithm are used to obtain super-pixel image by segmenting the PauliRGB image in order to reduce computational complexity and save computing time. Then, VAT-DBE algorithm is used to estimate and obtain the number of clusters of the image automatically. Combing the polarization information, the super-pixel image is classified by the method of spectral clustering. After that, the suspected airport runway area is extracted according to the scattering characteristics of the runway and classification result. Finally, the airport runway area is detected by using structural and topological characteristics of the runways. The experimental results show that the proposed algorithm can detect the airport runway area effectively with a clear outline, complete structure, and low false alarm rate. It also needs less time and a priori information compared with other methods.

We have proposed and developed a new wireless-optical signal converter utilizing stacked-patch antennas with a narrow gap and electro-optic (EO) crystal films for millimeter-wave radio-over-fiber systems. This converting device utilizes a structure of vertically stacked-patch antennas like the Yagi–Uda antenna, with a hybrid substrate composed of EO crystal films and low-dielectric-constant material plates. The electric field for wireless-optical signal conversion and the size of the patch antenna are increased by introducing the antenna and substrate stacked structure. Therefore, the conversion efficiency from wireless to optical signals can be improved. In the analysis by use of HFSS, the operational frequency was shifted to the higher range by 7 GHz, and the optical modulation index was improved by 3.2 dB with the double-stacked structure. In the experiments, the operational frequency shift by 8 GHz and the modulation index improvement by 3.0 dB were verified successfully, and the measured frequency response and directivity were in good agreement with the designed ones. The conversion of wireless 60 GHz band signals with QPSK modulation and the transfer of the converted signal over 1 km long fiber were also demonstrated.

This paper reports on photonic multiuser 5G hot-spots, that provide multiple beams by employing frequency steerable leaky-wave antennas. Therefore, a 60 GHz periodic leaky-wave antenna (LWA) has been developed, based on low loss substrate-integrated waveguide (SIW) technology, which is fabricated through standard PCB processes. The developed LWA operates in the V-band between 50 and 70 GHz and provides over 40° beam steering in the H-plane via frequency scanning. The capability for beam steering and multiple simultaneous beams from only one feeding port is combined with Radio-over-Fiber (RoF) techniques to provide a simple, compact and low-cost system for new applications in mm-wave communications. The proposed system enables centralized photonic beam steering in fiber-wireless transmission links, where up to 6 Gbit/s data rates are demonstrated using 64 QAM with IF-OFDM and simple receiver architectures. The multibeam capabilities provide a strong addition to RoF links by utilizing dense WDM channels to support multiple wireless users. Thereby, multiple low latency and high data rate wireless services can be provided via a single fiber-fed antenna. Finally, this concept is demonstrated by lab experiments, where three 1 Gbit/s OOK data signals were simultaneously transmitted and by a week-long field trial in a shopping mall, where two 1.5 Gbit/s real-time SDI video streams were transmitted.

We present an efficient approach for reconstructing images of small objects and Foreign Object Debris (FODs) from scattered field synthetic data and measurements in W-band (75−110 GHz), taking advantages of spatial and polarization diversities, and process them with either qualitative or quantitative inverse methods. The target application is FOD detection for airport runways. We investigate FOD detection and identification capabilities through two approaches: a quantitative reconstruction under 2D assumption and qualitative reconstruction using a Backpropagation algorithm (BP). Most existing systems are monostatic but rapid advances in millimeter-wave technologies make it realistic to imagine the deployment of multistatic radars on either side of airport runways. In the following, we investigate the contribution of multistatic measurements, on the reconstruction of typical debris, courtesy of DGAC (French Civil Aviation).

We demonstrated a 300-GHz bistatic radar system based on a radio signal over a fiber network to enhance the detection probability under a transmitter and two-receiver configuration. Fiber network management using optical frequency-modulated continuous waves is also discussed with fiber length measurement technique.

HF-START is HF Simulator Targeting for All-users’ Regional Telecommunications. This paper addresses the problems of worldwide existing radio propagation model and challenge on developing the HF-START. Its possible extension in the future is discussed. Meteorological information for aircraft in flight is broadcasted from worldwide radio stations in the frequency range of 3–15 MHz. Such frequency range is strongly affected from day-to-day bottom structure variation of the Earth’s ionosphere, where it is influenced by both space weather and upper atmosphere activities. Space weather is thus significant to aeronautical users, who deal with the critical radio application. Space weather data is, however, difficult to be understood. To translate research level data to user level data, radio propagation simulator named HF-START is being developed. Space weather disturbances-triggered failure of communications/navigation is of high priority to forecast.