Communication , Navigation And Surveillance Research Articles

Standardized Extraction of Air Traffic Control Hazard Features Based on Expert Knowledge

Air traffic control (ATC) hazard feature extraction is a key information retrieval task for air traffic hazard records. While text-based feature extraction ranks term importance based solely on statistical results, we aim to use external knowledge to extract features that meet the definition of hazards. This paper proposes a feature extraction method based on expert knowledge to define hazard features and construct a hazard analysis framework. We illustrate the model training process using communication navigation and surveillance (CNS) data, which includes candidate feature generation, feature vectorization, and cluster-based standardization. The correct structure of terms in hazard records, the vector distribution of candidate features, and the clustering effect of different methods are briefly explored. The algorithm refines and accumulates expert knowledge through iteration. The experiment results demonstrate that the dataset obtained after specific linguistic processing based on expert knowledge could extract more informative candidate features to construct analysis context by k-means. The proposed model outperformed four comparative algorithms in accuracy, reaching 82% and 86% in the air traffic control operation (ATCO) dataset and the CNS dataset, respectively. Additionally, the information-rich hazard features support safety management departments’ decision-making, reducing the cost of investigating hidden hazards.

Collision risk assessment of reduced aircraft separation minima in procedural airspace using advanced communication and navigation

With the advancement of Communication, Navigation and Surveillance (CNS) technologies such as space-based Automatic Dependent Surveillance-Broadcast/Contract (ADS-B/C), large separation minima may be reduced in procedural airspaces. It is of great significance to know the upper limit of the Reduced Separation Minima (RSM) for a procedural airspace and the corresponding consequences on collision risk with specifics of the advanced ADS-B and control intervention model. In this work, an interactive software is first developed for collision risk estimation. This software integrates the International Civil Aviation Organization (ICAO) collision risk models for lateral and longitudinal collision risk calculation for the Singapore procedural airspace. Results demonstrate that the lateral and longitudinal collision risk of Singapore procedural airspace with respect to current control procedures meets the ICAO Target Level of Safety (TLS) standard. Moreover, the feasibility of reducing the horizontal separations implemented in the Singapore procedural airspace with respect to advanced CNS techniques is investigated. It is found that if advanced CNS technologies are applied, then the current 50-NM lateral and longitudinal separation standards can be reduced to 22 NM (1 NM = 1.825 km) and 20 NM, respectively, to meet the TLS standards based on current demand. A method is then devised to expand the traffic demand by p for p ∈ [10%, 200%]. It is found that the minimum lateral and longitudinal separations can be reduced from 50 NM to be within the range of [23, 31] NM, and 20 NM, respectively, for p ∈ [10%, 200%], while the collision risk still meets the TLS standards.

Implementation of African Satellite Augmentation System (ASAS) for Maritime Applications

This paper introduces implementation of the new project known as African Satellite Augmentation System (ASAS) for Africa and Middle East, designed by the CNS Systems Company and its research group supported by partners. The ASAS project as Regional Satellite Augmentation Systems (RSAS) will provide service for maritime, land (road and rail), and aeronautical applications. Thus, with existing and other newly designed RSAS networks, it will be integrated in Global Satellite Augmentation System (GSAS) with new Satellite Communication, Navigation and Surveillance (CNS) for improved Ship Traffic Control (STC) and Ship Traffic Management (STM). This System also enhances safety and emergency systems, transport security and control of ocean shipping freight, logistics and the security of the crew and passengers onboard ships and fishing vessels as well. The current CNS infrastructures of the first generation of Global Navigation Satellite System (GNSS-1) applications are represented by old fundamental solutions for Position, Velocity, and Time (PVT) of the satellite navigation and determination systems, such as the US GPS and Russian (former USSR) GLONASS military requirements, respectively. The establishment of Space, Ground, and User segment, including Local Satellite Augmentation System (LSAS), are discussed as a new basic infrastructures for maritime and other mobile applications, which will be integrated with RSAS in the future GSAS network.

Feature Extraction Method Based on Sparse Autoencoder for Air Traffic Management System Security Situation Awareness

In wide-area distributed scenarios, it is particularly important to carry out information security situational awareness for the air traffic management (ATM) system with integrated air-ground structure. The operation data of the communication, navigation and surveillance (CNS) equipment of ATM system have the characteristics of multi-dimension, complexity, and strong correlation. In the process of situation awareness feature extraction, there are problems such as poor model accuracy, weak feature expression ability, and low classification performance. A feature association algorithm is designed to solve the above problems. Based on this algorithm, a deep-related sparse autoencoder (DRSAE) model based on improved sparse autoencoder is established. In DRSAE model, L1 regularization and Kullback–Leibler divergence (KLD) sparsity terms are used to penalize the parameters of the encoder network, and the quantity of hidden layers is increased to allow the model to optimize the global encoder network by iteratively training a single encoder. Moreover, the proposed DRSAE model and other feature extraction models such as principal component analysis (PCA), autoencoder (AE), and sparse autoencoder (SAE) are compared and evaluated by using the support vector machine (SVM) classifier. Compared with other feature extraction models, it is found that the proposed DRSAE model has good robustness in feature extraction of ATM system, and the obtained features have strong expression ability, which enhances the classification performance of the model and is convenient for situation awareness.

Exploring economic feasibility for airport shuttle service of urban air mobility (UAM)

UAM is a new concept of mobility that expands the two-dimensional transportation system to three dimensions using a personal air vehicle (PAV). This study explores the economic feasibility of the UAM airport shuttle service from two perspectives. First, this study estimates the fare of UAM services to attract customers. The UAM service should maintain a competitive price to convert existing transportation users into UAM users. This study used Incheon Airport (ICN) ground transportation data to estimate a competitive fare based on the multinomial logit model. The pricing range at which UAM services can obtain users from Seoul Station to ICN is estimated to be 96 to 108 USD, assuming the new service reduces traveling time by 30–40 min compared to taxi service. The comparison with professional institutions indicates that the 96–108 USD price range is feasible. However, according to a simulation based on the discounted cash flow (DCF) method, other approaches to increase economic feasibility are required. Second, this study reviewed operational policies to improve the economic feasibility of UAM shuttle services from two perspectives. The first is a service perspective that introduces new services or enhances the current service level. The internalization of CNS (communications, navigation, and surveillance) and UTM (unmanned traffic management) services can be a new business area, including premium routing. The second is introducing a dynamic pricing policy. Segmented pricing, time-based pricing, and changing market conditions strategies can practically strengthen the economic feasibility. Operating an airport Vertiport providing a dedicated path for UAM passengers can allow UAM operators to charge more on a premium passenger segment by shortening airport procedure time. Because it can avoid the uncertainty of road congestion, there is plenty of incentive to set higher fares during peak times with severe congestion. In addition, by creating a market environment in which multiple operators participate, the operators can share the burden of infrastructure construction and operation, which account for more than 80% of the total operating costs, increasing the economic feasibility of services.

A Unified Airspace Risk Management Framework for UAS Operations

Collision risk modelling has a long history in the aviation industry, with mature models currently utilised for the strategic planning of airspace sectors and air routes. However, the progressive introduction of Unmanned Aircraft Systems (UAS) and other forms of air mobility poses new challenges, compounded by a growing need to address both offline and online operational requirements. To address the associated gaps in the existing airspace risk assessment models, this article proposes a comprehensive risk management framework, which relies on a novel methodology to model UAS collision risk in all classes of airspace. This methodology inherently accounts for the performance of Communication, Navigation and Surveillance (CNS) systems, and, as such, it can be applied to both strategic and tactical operational timeframes. Additionally, the proposed approach can be applied inversely to determine CNS performance requirements given a target value of collision probability. This new risk assessment methodology is based on a rigorous analysis of the CNS error characteristics and transformation of the associated models into the spatial domain to generate a protection volume around each predicted air traffic conflict. Additionally, a methodology to quickly and conservatively evaluate the multi-integral formulation of collision probability is introduced. The validity of the proposed framework is tested using representative CNS performance parameters in two simulation case studies targeting, respectively, a terminal manoeuvring area and an enroute scenario.

A Performance-Based Airspace Model for Unmanned Aircraft Systems Traffic Management

Recent evolutions of the Unmanned Aircraft Systems (UAS) Traffic Management (UTM) concept are driving the introduction of new airspace structures and classifications, which must be suitable for low-altitude airspace and provide the required level of safety and flexibility, particularly in dense urban and suburban areas. Therefore, airspace classifications and structures need to evolve based on appropriate performance metrics, while new models and tools are needed to address UTM operational requirements, with an increasing focus on the coexistence of manned and unmanned Urban Air Mobility (UAM) vehicles and associated Communication, Navigation and Surveillance (CNS) infrastructure. This paper presents a novel airspace model for UTM adopting Performance-Based Operation (PBO) criteria, and specifically addressing urban airspace requirements. In particular, a novel airspace discretisation methodology is introduced, which allows dynamic management of airspace resources based on navigation and surveillance performance. Additionally, an airspace sectorisation methodology is developed balancing the trade-off between communication overhead and computational complexity of trajectory planning and re-planning. Two simulation case studies are conducted: over the skyline and below the skyline in Melbourne central business district, utilising Global Navigation Satellite Systems (GNSS) and Automatic Dependent Surveillance-Broadcast (ADS-B). The results confirm that the proposed airspace sectorisation methodology promotes operational safety and efficiency and enhances the UTM operators’ situational awareness under dense traffic conditions introducing a new effective 3D airspace visualisation scheme, which is suitable both for mission planning and pre-tactical UTM operations. Additionally, the proposed performance-based methodology can accommodate the diversity of infrastructure and vehicle performance requirements currently envisaged in the UTM context. This facilitates the adoption of this methodology for low-level airspace integration of UAS (which may differ significantly in terms of their avionics CNS capabilities) and set foundations for future work on tactical online UTM operations.

Space Remote Sensing and Detecting Systems of Oceangoing Ships

This paper introduces the implementation of space remote sensing and detecting systems of oceangoing ships as an alternative to the Radio – Automatic Identification System (R-AIS), Satellite – Automatic Identification System (S-AIS), Long Range Identification and Tracking (LRIT), and other current vessel tracking systems. In this paper will be not included a new project known as a Global Ship Tracking (GST) as an autonomous and discrete satellite network designed by the Space Science Centre (SSC) for research and postgraduate studies in Satellite Communication, Navigation and Surveillance (CNS) at Durban University of Technology (DUT). The ship detection from satellite remote sensing imagery system is a crucial application for maritime safety and security, which includes among others ship tracking, detecting and traffic surveillance, oil spill detection service, and discharge control, sea pollution monitoring, sea ice monitoring service, and protection against illegal fisheries activities. The establishment of a modern sea surface and ships monitoring system needs enhancement of the Satellite Synthetic Aperture Radar (SSAR) that is here discussed as a modern observation infrastructure integrated with Ships Surveillance and Detecting via SSAR TerraSAR-X Spacecraft, Ships Surveillance and Detecting via SSAR Radarsat Spacecraft and Vessels Detecting System (VDS) via SSAR.

Evaluation of Alternative Navigation, Positioning and Timing Systems Based on Their Performance and Additional Characteristics

The aim of this paper is to provide performance assessment of Alternative Navigation Positioning and Timing (APNT) systems considered possible GNSS backup in European region. The performance of the APNT systems is assessed based on their performance characteristics such as accuracy, integrity, and by additional beneficial abilities, that could help by implementation or could provide different added value in terms of solving certain issues in the Communication, Navigation and Surveillance (CNS) domain.

Architecture of the regional satellite augmentation system for maritime applications

This paper describes architecture of regional satellite augmentation system (RSAS) in the function of the maritime space communications, navigation and surveillance (CNS) and global navigation satellite systems (GNSS) networks for enhanced safety and surveying of oceangoing ships, management and tracking of cargo, security of Mariners onboard commercial and passenger ships, yachts, sea platforms and other types of craft. The RSAS network are designed to improve vessel management and transport operation because of the enormous expansion of the world's merchant fleet. However, this network with a special ship tracking system can also improve the protection of merchant ships and their crews against piracy, violence, robbery and terrorist attacks. The international maritime organization (IMO) and shipping flag states have project for development of the international ship and port security (ISPS) and design to implement an approaching and port control system (APCS) by special code for all merchant vessels including determination, tracking and positioning of all ships movements in and out of the seaport area. The Maritime RSAS and CNS systems are integration components of the global satellite augmentation systems (GSAS) of two operational GNSS-1 military networks, such as the US global position system (GPS) and Russian global satellite navigation system (GLONASS). In this paper are also introduced the special effects of the ships RSAS networks and coastal movement guidance and control (CMGC) system for maritime application at sea and in seaports areas.

Architecture of the global navigation satellite system for maritime applications

This paper introduces architecture of the global navigation satellite system (GNSS) networks in the function of the maritime space communications, navigation and surveillance (CNS) for enhanced navigation and positioning of vessels deploying passive, active and hybrid global determination satellite systems (GDSS) networks. These GNSS networks have to enhance safety and control oceangoing ships in navigation across the ocean and inland waters, to improve logistics and freight of goods, security of crew and passengers onboard ships. The maritime GNSS networks integrated with geostationary earth orbit (GEO) satellite constellations are providing important global satellite augmentation systems (GSAS) architecture, which is established by two first generations known GNSS as GNSS-1 infrastructures. The GNSS-1 network is the composition of two subnets such as the US global position system (GPS) and Russian global satellite navigation system (GLONASS). Both GNSS-1 networks play a significant contribution in very precise timing, tracking, guidance, determination and navigation of the oceangoing ships. At this point, both GNSS-1 networks, GPS and GLONASS, are used in maritime and many other mobile and fixed applications to provide enhanced accuracy and high integrity monitoring usable for positioning of the oceangoing ships. To provide improvements of GNSS-1 network it will be necessary to carry out their augmentation within several regional satellite augmentation systems (RSAS) as integration parts of GSAS infrastructures.

Practical implementation of 4D-trajectories in air traffic management: system requirements and time windows monitoring

PurposeThe current air traffic management (ATM) operational approach is changing; “time” is now integrated as an additional fourth dimension on trajectories. This notion will impose on aircraft the compliance of accurate arrival times over designated checkpoints (CPs), called time windows (TWs). This paper aims to clarify the basic requirements and foundations for the practical implementation of this functional framework.Design/methodology/approachThis paper reviews the operational deployment of 4D trajectories, by defining its relationship with other concepts and systems of the future ATM and communications, navigation and surveillance (CNS) context. This allows to establish the main tools that should be considered to ease the application of the 4D-trajectories approach. This paper appraises how 4D trajectories must be managed and planned (negotiation, synchronization, modification and verification processes). Then, based on the evolution of a simulated 4D trajectory, the necessary corrective measures by evaluating the degradation tolerances and conditions are described and introduced.FindingsThe proposed TWs model can control the time tolerance within less than 100 s along the passing CPs of a generic trajectory, which is in line with the expected future ATM time-performance requirements.Originality/valueThe main contribution of this work is the provision of a holistic vision of the systems and concepts that will be necessary to implement the new 4D-trajectory concept efficiently, thus enhancing performance. It also proposes tolerance windows for trajectory degradation, to understand both when an update is necessary and what are the conditions required for pilots and air traffic controllers to provide this update.

Implementation of innovative aeronautical communication, navigation and surveillance (CNS) systems

This paper introduces implementation of innovative Satellite Communication, Navigation and Surveillance (CNS) systems in function of Global Satellite Augmentation System (GSAS) integrated by the current and new projected Regional Satellite Augmentation System (RSAS) worldwide. The satellite communication and navigation systems are presently in use, however the main aspect of any hypothetical RSAS network is implementation of satellite surveillance system employing previous and new CNS solutions for improved Air Traffic Control (ATC) and Air Traffic Management (ATM) in all phases of flight, approaching to airports and during landing. The CNS network also enhances safety and emergency systems, transport security and control of transportation freight, logistics and the security of the crew and passengers onboard aircraft. The proposals for modern multifunctional space segment, DVB-RCS network, RSAS infrastructure, Satellite Automatic Dependent Surveillance-Broadcast SADS-B system for surveillance and movement guidance and control are also discussed as special solutions in airports environments.

Architecture of African satellite augmentation system (ASAS) for Africa and middle east

This paper introduces architecture of African Satellite Augmentation System (ASAS) project designed by African for Africa, with coverage of entire African Continent and Middle East for maritime, land (road and rail) and aeronautical applications. The ASAS network is de facto Regional Satellite Augmentation System (RSAS) as integration component of the Global Satellite Augmentation System (GSAS) employing current and new Satellite Communication, Navigation and Surveillance (CNS) for improved traffic control and management at sea, on land and in the air. This Network also enhances safety and emergency systems, transport security and control of transportation freight, logistics and the security of the crew and passengers onboard transport systems. The current infrastructures of the first generation of Global Navigation Satellite System (GNSS-1) applications are represented by old fundamental solutions for Position, Velocity and Time (PVT) of the satellite navigation and determination systems such as the US GPS and Russian (former-USSR) GLONASS military requirements, respectively. The establishment of Local Satellite Augmentation System (LSAS) and mobile movement guidance and control are also discussed as special infrastructures in seaports, land and airports environments.

Present and Future of Air Navigation: PBN Operations and Supporting Technologies

The present work reviews the new concept of operation that will be soon implemented in SESAR and NextGen (January 2020) using new state-of-the-art technology mainly based on onboard avionics: data link equipment, broadcast and surveillance systems, and Global Navigation Satellite System (GNSS) area augmentation. One of the main improvements of Performance-Based Navigation (PBN) is the use of satellites and more precise and accurate onboard instruments than current standard avionics related to ground-based navigation aids (VOR, NDB, DME, etc.). Air navigation systems have been without mayor updates for nearly 40 years, when most Very High Frequency Omnidirectional Range (VOR) and Tactical Air Navigation (TACAN) systems were implemented worldwide in the civil and military fields, respectively. These standard navigation systems lack new required performance navigation and required big deal of maintenance, especially in redundant systems. Recently, the development of new and precise GNSS and communication systems has allowed their use on different scenarios: Instrumental Flight Rules (IFR) departures, initial and final approaches, etc. Additionally, in several international airports, Ground Based Augmentation System (GBAS) approaches have been already successfully tested and implemented. Related to GBAS, the Automatic Dependent Surveillance Broadcast (ADS-B) is a cooperative technology that enhances pilots and controllers’ situation awareness, since ADS-B broadcasts own and other aircraft position. Controller Pilot Data Link Communications (CPDLC) may be another key element of the PBN concept of operations (CONOPS), since it provides air–ground data communications for the air traffic control (ATC) service and the aircrew, reducing risks associated to human factor: poor speaking, radio congestion, message confusion, standardization, etc. The main goal of this review is to present the PBN concept and the potentially supporting Communication, Navigation and Surveillance (CNS) systems, in the context of the NextGen and SESAR Air Traffic Management (ATM) modernization programmes.

Traffic management for drones flying in the city

Air Traffic Management (ATM) is designed based on the notion of a pilot navigating an aircraft from within the aircraft. Increasing demand for Unmanned Aircraft Systems (UAS) usage and its safe integration into segregated/non-segregated airspace, on the other hand, have raised a question on the adoption of the current ATM for the UAS Traffic Management (UTM). The Procedures for Air Navigation Services-Air Traffic Management (PAN-ATM) and Procedures for Air Navigation Services - aircraft operations (PAN-OPS) rules are both developed for manned flight operations. Therefore, this work (i) defines the UTM system and describes its envisioned functionalities; (ii) performs an exploratory research to identify the distinctions between a manned and an unmanned flight operation and consequently the possible challenges to implement UTM with regard to the ATM; (iii) discusses potential Communication, Navigation and Surveillance (CNS) technologies to support the UTM system; and (iv) proposes an architectural framework for UTM based on the findings. It is important to highlight that this work is developed based on the assumption that the UAS will operate in the class G airspace (500 ft and below) in urban areas where the UAS are exposed to various obstacles such as static objects: high-rise buildings, trees, lamp posts, over-ground rail tracks and dynamic objects: cranes.

Air traffic management based on 4D-trajectories: requirements and practical implementation

The current Air Traffic Management (ATM) functional approach is changing: ‘time’ is now integrated as an additional fourth dimension on trajectories. This notion will impose on aircraft the compliance of accurately arrival times over designated checkpoints, called Time Windows (TWs). In this context, we review the operational concept of 4D-trajectories, by initially developing an analysis of basic requirements for their implementation in the Communications, Navigation and Surveillance (CNS) systems and then by investigating their management in the future ATM context. We focus on defining the relationships between 4D-trajectories and other concepts and systems of the future ATM framework, and the needs that it will require for its application, detailing the main tools, programs and ATM/CNS systems that must be deployed. We appraise how 4D-trajectories must be managed and planned (negotiation, synchronization, modification and verification processes). Then, based on the degradation of a 4D-trajectory, we define and introduce the necessary corrective measures by evaluating the degradation tolerances and conditions.

IMPLEMENTATION OF THE GLOBAL AERONAUTICAL DISTRESS AND SAFETY SYSTEM (GADSS)

In this paper is introduced the first proposal for development of Global Aeronautical Distress and Safety System (GADSS) in 1999 by the author of this article. The GADSS is de facto the integration of space (radio and satellite) Communication, Navigation and Surveillance (CNS) with Tracking, Detecting and Search and Rescue (SAR) systems, which have to provide airmen with global communications and locating networks. The GPS, GLONASS and other Global Navigation Satellite Systems (GNSS) provide precise positioning data for vessels, land vehicles and aircraft, but modern CNS demands need for enhanced services and augmentation of GNSS networks. Both networks have to be integrated under an GADSS umbrella with elements capable of being operated by any individual onboard aircraft to ensure prompt distress alert for SAR procedure. The enhanced concept of GADSS is that SAR authorities ashore and ships in the immediate vicinity of the aircraft in distress have to be rapidly alerted via radio and satellite communication systems and to assist in a coordinated SAR operations with the minimum of delay. In 2016, 16 years in delay, the International Civil Aviation Organization (ICAO) has begun its process to amend international standards and recommended practices to align with GADSS concept. This paper will also introduce the necessary networks and equipment, which has to ensure harmonized and enhanced maritime and aeronautical global SAR systems.

UAV Navigation using Signals of Opportunity in Urban Environments: A Review

Abstract Novel Communication, Navigation and Surveillance (CNS) systems are currently developed targeting the Required Total System Performance (RTSP) levels. Within RTSP, it is essential to meet the Required Navigation Performance (RNP) in all flight phases, especially considering the Unmanned Aerial System (UAS) evolutions in the UAS Traffic Management (UTM) context. However, in dense urban environments characterized by tall buildings and complex structural variations, Global Navigation Satellite System (GNSS) is prone to data degradations or complete loss of signal due to multipath effects, interference or antenna obscuration. Furthermore, there is always a risk of jamming and spoofing of GNSS signals, with low cost civilian GNSS receivers being more vulnerable to a spoof attack. Therefore, a number of Signals of Opportunity (SoOP) techniques are explored to improve the RNP when Unmanned Aerial Vehicles (UAV) are employed in urban canyons. Electromagnetic signals found in urban environment including analogue/ digital radio, analogue/digital television, Wi-Fi, Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA) based signals are considered to model the system performance parameters. Implementation methods for using Signals of Opportunity such as Angle of Arrival (AOA), Time of Arrival (TOA), Received Signal Strength (RSS) and Time Difference of Arrival (TDOA) are modeled and compared. Integration of SoOP techniques in novel low-cost Navigation and Guidance Systems (NGS) is also investigated. As SoOP were not initially designed for navigation purposes, no single source of SoOP for navigation can work in all environments and hence a SoOP source has to be selected based on specific requirements in the considered urban environment. Constraints of power and weight on the UAV besides hardware and software costs are also factors that are considered when selecting appropriate SoOP signal sources. Hence, there is a clear opportunity to provide considerable savings in both infrastructure as well as energy costs and thus providing a low-cost and low-volume integrated NGS for trusted aerial autonomous operations.

Research on the Latest Maneuver Moment of Aircraft and the Minimum Safety Distance between Aircrafts in Free Flight

In order to guarantee the safety of flight in free flight environment, the minimum safety distance is needed to study. Considering the response delay of pilots and the lead time prior to initiating a maneuver, the latest maneuver moment is proposed. The position errors, which were affected by communication, navigation and surveillance (CNS) performances, were regarded as Brownian motion along the coordinate direction respectively. Then a model for collision risk in free flight environment was established basing on the stochastic differential equations. The latest maneuver moment can be obtained using dichotomy to optimize under the given Target Level of Safety (TLS). Introducing the time margin, the minimum safety distance is calculated. Finally, the feasibility of the model is verified by example.