ADS-B System Research Articles

A Secure and Effective Hierarchical Identity-Based Signature Scheme for ADS-B Systems

A Secure and Effective Hierarchical Identity-Based Signature Scheme for ADS-B Systems

Study of Trajectory Filtering Methods for ADS-B Based on VSIMM-RSRCKF

In this paper, an advanced ADS-B trajectory filtering method combining Variable Structure Interactive Multi-Modeling (VSIMM) and Reduced Square Root Volume Kalman Filter (RSRCKF) is proposed. After deeply analyzing the operational characteristics of ADS-B system and the application requirements in the field of aviation, this paper aims to improve the accuracy of ADS-B trajectory tracking by this novel filtering method. In order to cope with the tracking performance problems that may be caused by the model set selection in the traditional interacting multi-model algorithm, the Variable Structure Interacting Multi-Model (VSIMM-RSRCKF) algorithm based on the Simplified Square Root Volume Kalman Filtering is adopted in this study for trajectory filtering. By constructing a comprehensive VSIMM model set to describe the dynamic system of maneuvering targets, the filtering method in this paper simplifies the computational process and reduces the computational complexity by squaring the covariance matrix in the iteration, and at the same time ensures the non-negative qualitative nature of the covariance matrix, which effectively avoids the divergence problem that may occur in the filtering process. The goal of this research is to significantly improve the positioning accuracy and reliability of aircraft using the ADS-B system.

Design and simulation of rectangular patch microstrip antenna with inset feed for ADS-B system

The ADS-B system serves to track the location of aircraft. Ground station in the ADSB system is a receiver system that captures aircraft location signals using frequency 1090. Antenna is a key device for ADS-B communication. This paper is intended to develop a square microstrip antenna that has a working frequency of 1090 MHz. The material used is FR4 substrate, and the dielectric material is chopper. The antenna design is simulated using Matlab's Antenna Toolbox with its various conveniences. The simulation results of the patch antenna design with inset feed optimization resulted in a working frequency close to 1090 MHz, a VSWR value close to 1 and a Gain of 9.59 dBi.

ADS-B data gating technique and its probabilistic models

The article developed a gating technique that allows us to validate ADS-B data without the necessity to verify using the secondary surveillance radar or multilateration. Probabilistic models of the ADS-B data gating technique, as well as the algorithm for applying these models were proposed. Benchmark cases that occur when aircraft (A/C) positioning by ADS-B systems, determined by threshold values of navigation and pilot’s errors, were analyzed. The first benchmark case assumes not exceeding of navigation and pilot’s errors the bounds of the tolerance limits, which allows us to draw up a conclusion concerning the ADS-B data validation. The second one assumes exceeding of a pilot’s error the bounds of the tolerance limits under an allowable navigational error. Herewith, the air traffic controller (ATC) obtains a message about the proper ADS-B operation and the necessity to issue instructions to the pilot to correct a flight. The third benchmark case assumes exceeding of a navigation error the bounds of the tolerance limits under an allowable or not allowable pilot’s error. In this case, the ATC obtains a message about not valid ADS-B data and the incapability to use these systems. The simulation of the given benchmark cases was performed. In addition, the Rayleigh and Rice distributions were applied to implement the ADS-B data gating technique. The simulation results allow us to assess the required amount of accumulated ADS-B data for the evaluation. Thus, it was found that during the estimate based on the Rayleigh distribution, it is sufficient to accumulate 15–20 measurements, which, when transmitting 2 messages per second and under the condition of the normal ADS-B equipment operation, will take 8–10 s. During the estimate, using the Rice distribution, an accumulation of 25–30 measurements is sufficient, which will take 13–20 s. The developed method will allow the use of ADS-B systems at regional aerodromes with the low intensity of air traffic as the primary or sole surveillance means.

Computerized Ionospheric Tomography Based on the ADS-B System

The broadcast automatic dependent surveillance (ADS-B) system is a new-generation air traffic control system designed to avoid the waste of resources in secondary radars. The establishment of the spaceborne ADS-B system provides a broad prospect for ionospheric tomography. In this paper, the external observation information of the ionosphere is obtained by measuring the Faraday rotation angle, that is, the total electron content (TEC). Tomography research can be carried out all over the world to conduct large-scale ionospheric electron density research. The experiment selected two different regions and had a time resolution of two hours, a height resolution of 200 km, a latitude resolution of 2°, and a longitude resolution of 5°. Based on the simulated spaceborne ADS-B signal to invert the regional ionospheric electron density, the latitude, longitude, and height distributions of inversion result are basically consistent with those of the actual ionospheric electron density.

Original and Low-Cost ADS-B System to Fulfill Air Traffic Safety Obligations during High Power LIDAR Operation

LIDAR is an atmospheric sounding instrument based on the use of high-power lasers. The use of these lasers involves fulfilling obligations with respect to air safety. In this article, we present a low-cost air traffic surveillance solution integrated into an automated operating system for the Rayleigh-Mie-Raman LIDAR of Clermont Ferrand and the statistical elements of its application over more than two years of operation from September 2019 to March 2022. Air traffic surveillance that includes the possibility of shutting off lasers is required by international regulations because LIDAR is equipped with a class four laser that presents potential dangers to aircraft flying overhead. The original system presented in this article is based on software-defined radio. ADS-B transponder frames are analyzed in real-time, and laser emission is stopped during LIDAR operation when an aircraft is detected within a 2 km radius around the LIDAR. The system was accredited in 2019 by the French air traffic authorities. Laser shutdowns due to the detection of aircraft near the Clermont Ferrand LIDAR caused a data loss rate of less than 2% during the period of application.

Polynomial Chaos Expansion-Based Enhanced Gaussian Process Regression for Wind Velocity Field Estimation from Aircraft-Derived Data

This paper addresses the problem of spatiotemporal wind velocity field estimation for air traffic management applications. Using data obtained from aircraft, the eastward and northward components of the wind velocity field inside a specific air space are calculated as functions of time. Both short-term wind velocity field forecasting and wind velocity field reconstruction are performed. Wind velocity data are indirectly obtained from the states of the aircraft flying in the relevant airspace, which are broadcast by the ADS-B and Mode-S aircraft surveillance systems. The wind velocity field is estimated by combining two data-driven techniques: the polynomial chaos expansion and the Gaussian process regression. The former approximates the global behavior of the wind velocity field, whereas the latter approximates the local behavior. The eastward and northward wind components of the wind velocity field must be estimated, which causes the problem to be a multiple-output problem. This method enables the estimation of the wind velocity field at any spatiotemporal location using wind velocity observations from any spatiotemporal location, eliminating the need for spatial and temporal grids. Moreover, since the method proposed in this article allows for the probability distributions of the estimates to be computed, it causes the computation of the confidence intervals to be possible. Furthermore, since the method presented in this paper allows for data assimilation, it can be used online to continuously update the wind velocity field estimation. The method is tested on different wind scenarios and different training-test data configurations, by means of which the consistency between the results of the wind velocity field forecasting and the wind velocity field reconstruction is checked. Finally, the ERA5 meteorological reanalysis data of the European Centre for Medium-Range Weather Forecasts are used to validate the proposed technique. The results show that the method is able to reliably estimate the wind velocity field from aircraft-derived data.

GENERALIZED MODEL OF THE ADS-B UNMANNED AERIAL VEHICLE DATA TRANSMISSION PROCESS IN A STEGANOGRAPHIC SYSTEM

The subject of the article is a model of the ADS-B data transmission process of an unmanned aerial vehicle in a steganographic system using direct spectrum expansion technology. The aim of the publication is to improve the security of unmanned aerial vehicles with an integrated ADS-B system. Particular scientific tasks: analysis of basic methods of ADS-B format data protection; development of the scheme of ADS-B drone data transfer in steganographic system with the use of direct spectrum expansion technology; improvement of the model of ADS-B drone data transfer in steganographic system with the use of direct spectrum expansion technology; determination of qualitative and quantitative characteristics as well as security properties of ADS-B format data. The following research results were obtained: as the result of the scientific works analysis the hypothesis about the perspectives of the ADS-B format steganographic data protection usage was put forward; the scheme of an unmanned aerial vehicle ADS-B data transmission in the steganographic system with the usage of the direct spectrum spreading technology was developed; the main safety properties as well as the safety parameters and characteristics of the ADS-B format information signal were formulated; the generalized model of an unmanned aerial vehicle ADS-B data transmission was further developed. This will improve the safety of UAVs. The advantages and disadvantages of the model were revealed, which allowed to determine the priority of further research and possible promising ways of solving the assigned tasks.

МЕТОД ОБЕСПЕЧЕНИЯ ЗАЩИТЫ ПЕРЕДАВАЕМЫХ СООБЩЕНИЙ В СИСТЕМЕ ADS-B С ИСПОЛЬЗОВАНИЕМ АППАРАТА КЛЕТОЧНЫХ АВТОМАТОВ

The purpose of the study is to develop a method for encoding of transmitted ADS-B messagesbetween aircraft. The open format 1090ES of transmitted data is critical in terms of carryingout various types of attacks that can lead to a violation of the safety of aircraft operations.The work is aimed at using means of encoding and decoding messages with a private key. Researchmethods are based on the application and development of streaming data encryption usingone-dimensional cellular automata. They operate as a generator of pseudo-random sequences thattransform the elementary states of a cell of a one-dimensional cellular automaton based on typicalhardware-oriented operations. The processes of encoding and decoding data fields are based onan analytical expression using typical logical operations (or, xor). This property allows parallelprocessing of message data fields. The result is the created method for ensuring the protection oftransmitted data, additionally encoding on transmission and decoding on message reception.A distinctive feature of the method is the preservation of the protocol forma. The method uses aone-dimensional cellular automaton that encodes and decodes the target fields (coordinates, heading,etc.) using a pseudo-random number generator. The developed method belongs to the class ofhardware-oriented methods. Critical for encoding and decoding properties of periodicity of datafields and key length are eliminated by choosing an initial irrational value and organizing the“streaming” work of the encoder. If the encoding automaton is running in streaming mode, thecurrent value depends on the history of some depth, determining the length of the "automatic key"from the ADS-B message will be algorithmically impossible due to data loss. The linear complexityof the method allows you to perform transformations at the data rate. Conclusion: the developmentof hardware-oriented methods of data encoding makes it possible to increase the efficiency ofusing the ADS-B system by counteracting various types of destructive actions.

COMPARATIVE STUDIES OF METHODS FOR IMPROVING THE CYBER SECURITY OF UNMANNED AERIAL VEHICLES WITH THE BUILT-IN ADS-B SYSTEM

The subject of study in the article is methods for improving the cybersecurity of unmanned aerial vehicles with an integrated ADS-B system. The aim is to analyze and compare methods for improving the cybersecurity of unmanned aerial vehicles with an embedded ADS-B system. Particular scientific tasks: analysis and comparative studies of the main types of cyber threats and methods for improving the cybersecurity of unmanned aerial vehicles with an integrated ADS-B system, the development of an appropriate taxonomy, and the development of proposals for further research. The methods used in the article are the methods of system analysis. The following research results have been obtained: a classification of cyber threats to the security of unmanned aerial vehicles with an integrated ADS-B system has been developed; a taxonomy of ADS-B message modification and injection attacks has been developed; practical UAV security metrics adapted to the presented taxonomy of cyberattacks are defined and researched ; chosen most priority directions research ; - a generalized classification of cryptographic protection methods adapted to solve the problems of improving the security of UAVs with an integrated ADS-B system has been developed; the use of additional means of identification based on steganographic methods of data protection is proposed. Conclusions. An analysis and comparative studies have been carried out, and a generalized classification of methods for improving the cybersecurity of unmanned aerial vehicles with an integrated ADS-B system has been developed. Their advantages and disadvantages are revealed, which made it possible to determine the priority of further research and possible promising ways to solve the tasks.

Verification of influence of the solar flare from September 2017 to ADS-B NAC parameter

This paper dissertates about the influence of space weather event from September 2017 on parameters NAC and NIC in ADS-B messages. Space weather have potential to influence GNSS navigation. Especially in the aviation, where we depend on th GNSS more. Therefore we examined the influence of solar flares on the aviation navigation system of commercial aircraft. We used data broadcasted by ADS-B system during the most severe space weather event. Parameters NAC and NIC describe the level of reliability of the aircraft position information based on the GNSS. Therefore, they might be partially used as sensors of any irregularities in GNSS signal. We focus on these parameters during one of the most severe solar flare in recent years to establish if there is any observable influence of the space weather on these parameters. We were able to prove that even during this severe flare that there was no degradation in the availability of the GNSS.

Обоснование подхода к снижению вариативности геометрического фактора системы определения координат воздушных объектов по технологии MLAT.

Estimating results of the MLAT technology capabilities regarding accuracy of air basing radio sources positioning using ADS-B system signals depending on receiving points system geometric configuration are presented. Based on the obtained results, geometric configuration parameters of the MLAT system which most significantly affect the accuracy of estimating the airborne sources coordinates in the monitoring area are identified. The variant of the receiving points placement in control area which ensures a decrease in uncertainty level regarding coordinate estimation accuracy is proposed.

Lateral collision risk assessment of parallel routes in ocean area based on space-based ADS-B

In order to ensure the safe operation of parallel routes in the ocean area, it is necessary to assess the risk of lateral collision of routes. The data used in the assessment often come from the real flights, while the traditional land-based ADS-B equipment has limited coverage and cannot be used for research. The space-based ADS-B system can receive and send the flight position of the aircraft over the ocean area. In this paper, the ocean tracks in space-based ADS-B data are first extracted. According to the different route structures, the data of fixed route and flexible route are preprocessed by segmented Kalman filter and cubic polynomial fitting method respectively. Then the processed track position error is calculated, and Q-Q (Quantile-Quantile) median method is used to test the normal distribution of the error, and k-means clustering is used to obtain the clustering center and occurrence frequency of positioning error and flight error. Finally, a collision risk model based on Bayesian network is established, and the error distribution parameters and occurrence frequency are brought into the model to evaluate the collision risk of parallel routes in the ocean area. The results show that the lateral collision risk based on space-based ADS-B ocean flight data is lower than 0.5 × 10−8 times/hour specified by ICAO when the fixed route separation is 14n miles and the flexible route separation is 49n miles. And the actual lateral interval of the Pacific flexible route is 50n miles (Jiang, 2010), which meets the safety target level.

Spufing u avijaciji - bezbednosne pretnje po GPS i ADS-B sisteme

Introduction/purpose: The paper provides a review of recent research in the field of GPS and ADS-B spoofing. Systems that rely on satellite positioning technology can be targeted by spoofing in order to generate incorrect positioning/timing, which is accomplished by inserting false signals into the "victim's" receiver. Attackers try to insert false positioning information into systems that, for example, provide navigation of airplanes or drones for the purpose of hijacking or distracting security/safety in airspace surveillance. New concepts of navigation and ATC will thus be necessary. Methods: Using a scientific approach, the paper gives an evaluation of GPS and ADS-B spoofing/antispoofing and how spoofing affects the cyber security of aviation systems. Results: Based on the methodological analysis used, the importance of studying spoofing/anti-spoofing in aviation is shown. Conclusion: Although spoofing in aviation is only a potential threat, its technical feasibility is realistic and its potential is considerable; it becomes more flexible and cheaper due to very rapid advancement of SDR technologies. The real risk, in the time to come, are potential spoofing attacks that could occur from the air, using drones. However, aircraft systems are not exposed to spoofing without any defense; receivers can detect it by applying various anti-spufing techniques. Also, pilots are able to detect and solve problems at every stage of the flight. However, due to a possibility of more sophisticated spoofing attacks, international organizations such as ICAO are proactively working to increase GPS and ADS-B systems robustness on spoofing.

Spufing u civilnoj avijaciji - bezbednosnost i sigurnosnost GPS/GNSS i ADS-B sistema

Aircraft systems that rely on satellite positioning technology, such as GNSS and ADS-B, can be the target of a spoofing attack - a sophisticated and very dangerous form of radio frequency interference in which false signals are inserted into the "victim's" receiver for incorrect positioning or timing. Although spoofing in civil aviation is a potential threat, its technical feasibility is realistic, and the application of spoofing is becoming more flexible due to the very rapid progress of cheap SDR platforms. In particular, the potential risk is posed by potential air strikes, using unmanned aerial vehicles/drones, for the purpose of hijacking or distracting security in airspace surveillance. However, aviation is not ruthlessly exposed to spoofing attacks without any defense; by applying certain methods/techniques, spoofing can be mitigated in the GNSS receiver. Also, pilots are trained to detect and solve problems at every stage of the flight. Due to more sophisticated forms of terrorist attacks are possible, international organizations, such as ICAO and EUROCA, are proactively working to increase the robustness of the GNSS and ADS-B systems to spoofing. Given the importance of the topic and the fact that spoofing/antispuffing testing has certain limitations, consideration of the specifics and different scenarios of these attacks are very important in the development of new methods for their mitigation and detection. This paper focuses on spoofing/antispuffing of GNSS and ABS-B systems in civil aviation and provides an overview of the latest research in these areas.

A Reliable Separation Algorithm of ADS-B Signal Based on Time Domain

With the development of Aerospace Science and technology, automatic dependent surveillance-broadcast has become a core technique in the field of air surveillance. Installing ADS-B receiver on LEO satellite can solve the problem of small coverage of ground receiver, to realize global coverage and monitoring. However, the satellite ADS-B system is faced with serious collision and overlap problems, which has a serious impact on the signal decoding, leading to the wrong decoding or even loss of important information. In this paper, a time-domain ADS-B blind signal separation algorithm is proposed. When there is a certain power difference between the two source signals, the overlap signals are offset by the high-power signal and low-power signal to get the corresponding cancellation signals. According to the superposition mode of different pulses, different bit decision results are obtained according to the amplitude, to recover the source signal. Simulations demonstrate that the proposed algorithm is feasible and has a lower bit error rate.

Adversarial Examples on Deep-Learning-Based ADS-B Spoofing Detection

Deep neural networks have been applied to many tasks in air traffic management, ranging from anomaly detection to flight trajectory prediction. However, it has been shown that such algorithms are susceptible to adversarial examples. In this letter, we manage to show that current deep learning algorithms proposed for spoofing detection are vulnerable to maliciously crafted ADS-B data. To inject the false messages into the ADS-B system without being detected, we need to find adversarial perturbations to balance the need of overwhelming the channel noise and keeping the decoding error low. Simulation results demonstrate the viability of our approach to evade the DNN-based spoofing detector without increasing the decoding error.

Backward Compatible Physical Layer Protocol Evolution for ADS-B Message Authentication

The automatic dependent surveillance-broadcast system is a pillar of the future air traffic control system. It is a surveillance system in which air planes transmit their information (identity, position, velocity, etc.) in broadcast to any listener equipped with a receiver. Networks of ADS-B receivers have been installed all over the world, producing a clear traffic awareness for air traffic controllers. For historical reasons, this protocol does not have any authentication/encryption mechanism. The aim of this article is to improve the ADS-B system security by introducing a physical layer protocol modification for the introduction of an authentication scheme. The proposed evolution fully complies with the current standard and exploits the phase modulation to increase the number of bits that can be transmitted with a single packet of data. These additional bits can be used to carry authentication information, making the overall system more secure (and safe). The proposed protocol evolution is developed ensuring backward compatibility and respecting the ICAO and RTCA recommendations; it can be introduced and used together with the present standard in a mixed scenario, allowing a smooth transition from the present protocol to the new one. Protocol performances were evaluated by simulations and, moreover, its feasibility and compliance with recommendations were tested using a software-defined radio (as transmitter) and a laboratory ADS-B receiver.

Go-Around Detection Using Crowd-Sourced ADS-B Position Data

The decision of a flight crew to undertake a go-around, aborting a landing attempt, is primarily to ensure the safe conduct of a flight. Although go-arounds are rare, they do cause air traffic disruption, especially in busy airspace, due to the need to accommodate an aircraft in an unusual position, and a go-around can also result in knock-on delays due to the time taken for the aircraft to re-position, fit into the landing sequence and execute a successful landing. Therefore, it is important to understand and alleviate the factors that can result in a go-around. In this paper, I present a new method for automatically detecting go-around events in aircraft position data, such as that sent via the ADS-B system, and apply the method to one year of approach data for Chhatrapati Shivaji Maharaj International Airport (VABB) in Mumbai, India. I show that the method is significantly more accurate than other methods, detecting go-arounds with very few false positives or negatives. Finally, I use the new method to reveal that while there is no one cause for go-arounds at this airport, the majority can be attributed to weather and/or an unstable approach. I also show that one runway (14/32) has a significantly higher proportion of go-arounds than the other (09/27).

Intent Inference Based Trajectory Prediction and Smooth for UAS in Low-altitude Airspace with Geofence

In order to meet the higher accuracy requirement of trajectory prediction for Unmanned Aircraft System (UAS) in Unmanned Aircraft System Traffic Management (UTM), an Intent Based Trajectory Prediction and Smooth Based on Constrained State-dependent-transition Hybrid Estimation (CSDTHE-IBTPS) algorithm is proposed. Firstly, an intent inference method of UAS is constructed based on the information of ADS-B and geofence system. Moreover, a geofence layering algorithm is proposed. Secondly, the Flight Mode Change Points (FMCP) are used to define the relevant mode transition parameters and design the guard conditions, so as to generate the mode transition probability matrix and establish the continuous state-dependent-transition model. After that, the constrained Kalman filter (CKF) is applied to improve State-dependent-transition Hybrid Estimation (SDTHE) algorithm by applying equality constraint to the velocity of UAS in the straight phase and turning phase, respectively, and thus the constrained state-dependent-transition hybrid estimation (CSDTHE) algorithm is constructed. Finally, the results of intent inference and hybrid estimation are used to make trajectory prediction. Furthermore, each flight segment of trajectory is smoothed respectively by Rauch-Tung-Striebel (RTS) backward smooth method using the proposed CSDTHE-RTS algorithm, so as to obtain more accurate trajectory prediction results. The simulation shows that the proposed algorithm can reduce the errors of trajectory prediction and the time delay of intent inference.