Satellite Telecommunication Systems Research Articles

Exploring the Potential of V-Band for Satellite Communications

The current development in the scientific field indicates the ability to use v band in satellite communication. “This enhancement will enable the capacity of communication in GEO satellite system to be settled than before. During the last years, researches in geostationary telecommunication satellite systems had focused on the ability of satellite coverage for a wide area within broad banding context. This view had been changed under current investigations. Extended geostationary views in satellites had been challenged to remain able in the competitive context. This was due to its capacity, costs and supported services. The current situation showed its limited capacity, availability, flexibility, and inability to guarantee the required quality of service efficiently. These limitations expected to be resulted from the effects of radio-wave broadcast in atmospheric last layer. Lastly, “the attenuation and scintillation effects of atmospheric gas, clouds and rain become more severe by increasing the operating frequency.

IMPROVEMENT OF THE METHODOLOGY FOR EVALUATING THE CARRIER FREQUENCY OF THE SIGNAL DURING DATA TRANSMISSION IN TELECOMMUNICATION CONTROL AND DISTANCE LEARNING SYSTEMS

Effectiveness of the application of telecommunications systems is directly influenced by the effectiveness of the functioning of each component and device of its design. The article directly examines the issue of improving the carrier frequency estimation methodology for data transmission in telecommunication management and distance learning systems. The essence of the solution lies in proposals for improving the efficiency of frequency estimation at the input signal synchronization stage, which is presented on the example of a satellite telecommunication control system and distance learning. Namely, the analysis of modern satellite telecommunications systems was carried out and the features that affect the effectiveness of carrier frequency estimation and input signal synchronization were determined. The main inconsistencies are the low energy of the input signal receiving channel, significant signal frequency uncertainty, and the presence of "neighboring channels" receiving the input signal. It was determined that satellite communication systems during data transmission work in the mode with multi-station access in the variant of operation with frequency division of channels, which can receive data packets in the mode of multiple access or when providing a data reception channel on demand. At the same time, the operation of telecommunications systems can proceed both in continuous and in batch modes of receiving the input signal. It is considered that coherent processing of the input signal is carried out in demodulators of satellite telecommunications and interference-resistant coding is used. To solve the task of estimating the carrier frequency of the input signal in coherent demodulators of modern satellite telecommunications, considering the above-defined inconsistencies and features, the article proposes a methodical approach. The essence of this approach is to determine the potential boundary of variances of the obtained estimates of the carrier frequency and to develop algorithms for estimating the carrier frequency of the input signal separately for continuous and batch modes of input data transmission based on the fast Fourier transform. Keywords: Frequency, signal, uncertainty, carrier, estimation.

Method of determining the coordinates of the radio signal source in satellite communication systems

Telecommunications have penetrated deeply into all spheres of human activity. Due to the use of digital technologies, it has become possible to transmit and receive information of various kinds in one stream (not separately). Three geostationary satellites are sufficient to provide data transmission from anywhere in the world to another point using artificial Earth satellites. Data transmission systems using the satellite should contain at least two Earth Stations and a repeater of the communication satellite. There are no means of combating any types of artificial interference in the Earth Stations equipment. The jammer, an illegitimate user, can emit a signal from any point in space within a telecommunications satellite system. The paper provides an analysis of existing methods for determining the coordinates of a radio signal source, describes a method for determining the coordinates of an radio signal source (illegitimate user) in satellite telecommunications systems using a geostationary spacecraft. The development was based on a three-position virtual antenna array, the positions of which determined the base of an irregular tetrahedron, and the radio signal source itself was its vertex. In the course of the solution, canonical equations of straight lines in space were compiled, at the intersection point of which the source of the radio signal is located. The coordinates of the radio signal source were the roots of the system, when finding the unit vectors lying on these lines.

Microwave waveguide polarizer for satellite communication antennas with circular polarization

The volumes of information transmitted in modern satellite telecommunication systems are constantly increasing. Antennas with signal polarization processing, which is performed by polarizers, are the fundamental elements of such systems. Therefore, the development of methods for the analysis of new polarizers is an important problem. From a technological point of view, polarizers based on waveguides with irises are the simplest. Analysis and optimization of electromagnetic characteristics of a polarizer based on a square waveguide with irises are the goals of the presented research. To solve this optimization problem, we have created a new mathematical model, which allows investigating the influence of the design parameters of the polarizer on its electromagnetic characteristics. A mathematical model of the waveguide polarizer with irises was created by the method of decomposition using wave transmission and scattering matrices. Besides, the new mathematical model takes into account the thickness of the irises using their equivalent T- and П-shaped substitution circuits. The general wave scattering matrix is the basis of a new mathematical model of a waveguide polarizer. This matrix was determined using the theory of microwave circuits. The main characteristics of the waveguide polarizer were determined through the elements of this matrix. Here, we perform the optimization of the polarizer characteristics in the Ku-band 10.7–12.8 GHz. The developed new mathematical model of a waveguide polarizer with irises makes it possible to take into account the heights of the irises, distances between them and their thickness. The new mathematical model determines the electromagnetic characteristics of the polarizer in a simpler and faster way compared to the finite integration technique, which is often used for the analysis of microwave devices for various purposes

Ka-Band Reconfigurable Reflectarrays Using Varactor Technology for Space Applications: A proposed design

In this article, Ka-band reconfigurable reflectarray antennas based on varactor diodes are investigated. Varactor diodes enable high radiation pattern flexibility while maintaining acceptable costs. The design of a dual-band reconfigurable reflectarray based on varactor technology is described in detail. The antenna, considered for a fixed or mobile ground station for satellite telecommunications systems, could be used for several other applications. To demonstrate and validate experimentally the proposed concept, the design of a reduced-sized antenna is presented. The manufacturing and testing of its reconfigurable reflecting surface are then described and discussed. This antenna design could also be considered as a baseline for a data downlink antenna employed on a satellite.

ESTIMATION OF FEM AND FDTD METHODS FOR SIMULATION OF ELECTROMAGNETIC CHARACTERISTICS OF POLARIZATION TRANSFORMING DEVICES WITH DIAPHRAGMS

Context. Today, there is a rapid expansion of the range of modern branches of science and technology, which actively use satellite telecommunication systems to receive, process and transmit various information. These radioelectronic systems quite often require an increase of the volumes of information, which they are processing and transmitting. Increase of the volumes of transmitted information in two times can be achieved by using dual-polarization antenna systems and devices. Nowadays, most part of the specialists, who are engaged in the development of various modern polarization-processing microwave devices, carry out their numerical modeling and optimization using variational techniques, methods of integral equations, method of fields matching in partial regions. The methods with division of the internal region of the device into elementary cells are applied most actively. Among them in the time domain the most often used approach is finite difference method with the decomposition at hexagonal mesh, while and in the frequency domain the finite elements method with the adaptive tetrahedral mesh is applied. Therefore, the estimation of the speed and accuracy of these methods with the purpose of determination of more effective among them is a relevant problem. Objective. The goal of the research is comparison of speed and accuracy of the calculations of electromagnetic characteristics of waveguide polarizers using FEM and FDTD methods, as well as the comparison of the convergence of these methods for the analysis of polarization-processing microwave devices with diaphragms. Method. For the calculations and analysis of electromagnetic characteristics in the article we used the method of finite differences in the time domain (FDTD) and the method of finite elements in the frequency domain (FEM). In FEM the volume is split into the tetrahedral mesh cells. In FDTD the computational domain is divided into hexagonal mesh cells. Results. It was found that the convergence of voltage standing wave ratio for the waveguide polarizer is fast for both methods. It was obtained that the convergence of the characteristics of differential phase shift, axial ratio, and crosspolar discrimination of the developed microwave device turned out to be much more sensitive to the number of mesh cells used. Moreover, in the research it was obtained by calculations that the computation time by the finite elements method in the frequency domain is more than 2 times less than the corresponding time required for calculations by the finite difference time domain method. When using the finite elements method in the frequency domain the corresponding number of tetrahedral mesh cells is 10 times less than the number of hexagonal mesh cells, which are used in the finite difference time domain method. Conclusions. Performed investigations have shown that FEM in the frequency domain, which applies an adaptive tetrahedral mesh, is more efficient than the FDTD method for the calculations of phase and polarization characteristics of modern waveguide polarizers and other microwave devices for various applications.

Predicting Joint Effects on CubeSats to Enhance Internet of Things in GCC Region Using Artificial Neural Network

Satellite telecommunication systems promise to bridge digital gaps and deliver wireless communication services to any corner of the world. However, despite satellites’ global connectivity and wide footprint, still atmospheric and dust impairments are open challenges that face satellite systems, especially at high-frequency bands in arid and semiarid regions. Therefore, this paper aims to predict joint effects of atmospheric and dust attenuations in Gulf Cooperation Council (GCC) countries on CubeSat communications using Artificial Neural Network (ANN). The prediction model has been carried out using a massive Multiple-Input Multiple-Output (MIMO) antenna payload at K-frequency Bands. Consider these joint effects have positive relations in calculating satellites link margin, which leads to obtaining efficient communication system, delivering better quality of service (QoS), and enhancing Internet of Things (IoT) connectivity, or even Internet of Space Things (IoST). Predicated results infer that the ANN attenuation predictions, along with the 5G MIMO antenna on-board the CubeSat, offer much promise channel model for satellite communications, which in turn leads to not only supporting IoT connectivity but also reducing power consumption, thus enhancing lifetime of CubeSat. Also, this study can provide a reference for CubeSat engineers to guarantee large-capacity communication.

Pure and Linear Frequency-Conversion Temporal Metasurface

Metasurfaces are ultrathin structures which are constituted by an array of subwavelength scatterers with designable scattering responses. They have opened up unprecedented exciting opportunities for extraordinary wave engineering processes. On the other hand, frequency converters have drawn wide attention due to their vital applications in telecommunication systems, health care devices, radio astronomy, military radars and biological sensing systems. Here, we show that a spurious-free and linear frequency converter metasurface can be realized by leveraging unique properties of engineered transmissive temporal supercells. Such a metasurface is formed by time-modulated supercells; themselves are composed of temporal and static patch resonators and phase shifters. This represents the first frequency converter metasurface possessing large frequency conversion ratio with controllable frequency bands and transmission magnitude. In contrast to conventional nonlinear mixers, the proposed temporal frequency converter offers a linear response. In addition, by taking advantage of the proposed surface-interconnector-phaser-surface (SIPS) architecture, a spurious-free and linear frequency conversion is achievable, where all undesired mixing products are strongly suppressed. The proposed metasurface may be digitally controlled and programmed through a field programmable gate array. This makes the spurious-free and linear frequency converter metasurface a prominent solution for wireless and satellite telecommunication systems, as well as invisibility cloaks and radars. This study opens a way to realize more complicated and enhanced-efficiency spectrum-changing metasurface.

SIMULATION OF COMPACT POLARIZERS FOR SATELLITE TELECOMMUNICATION SYSTEMS WITH THE ACCOUNT OF THICKNESS OF IRISES

Background. One of the main problems in modern satellite telecommunication systems is to increase the volume of information transmission with simultaneous preservation of its quality. Key element of such systems is antenna systems with polarization processing, which is carried out using polarizers. Therefore, development of new polarizers and simple techniques for their analysis and optimization are important problems. The most simple, effective, technological and actual for analysis are polarizers based on waveguides with irises. Objective. The purpose of the paper is to create a mathematical model of the polarizer based on a square waveguide with irises, which allows analyzing the influence of polarizer’s design parameters on its electromagnetic characteristics. Methods. A mathematical model of the waveguide polarizer with irises is created by decomposition technique using transfer and scattering wave matrices. To take into account the irises’ thickness their equivalent T- and Π-shaped circuits were used. Results. We have developed mathematical model of the waveguide polarizer with irises, which takes into account their thickness and is based on the complete scattering wave matrix of the waveguide polarizer. The matrix has been obtained using the microwave circuit theory. The main characteristics of the waveguide polarizer were defined using matrix elements. The optimization of characteristics of a polarizer was carried out in the operating Ku-band 10.7–12.8 GHz. Conclusions. Suggested mathematical model of a waveguide polarizer with irises provides the account of heights of irises, distances between them and their thickness. The results obtained show that this model is simpler and faster for the calculation of electromagnetic characteristics compared to finite elements method, which is often used for analysis of microwave devices for various applications.

Разработка алгоритма приема и декодирования входного сигнала с применением МПД декодера для абонентских терминалов, работающих с низкоорбитальными космическими аппаратами

The relevance of the topic is determined by the need to increase the speed of data transmission in satellite telecommunication systems through the use of noise-proof coding. The speed of data transmission in a radio channel is actually determined by the level of interference present due to the fact that the radio transmission medium is a public environment and other electronic devices operate in it. The purpose of the article is to develop an algorithm for encoding and decoding the input signal using a multithreshold decoder (MTD) of rigid solutions for subscriber terminals operating with low-orbit spacecraft (NCA), and its comparison with a conventional PC decoder «Messi». The comparison allows us to conclude that the application of the developed algorithm is justified in systems where more stringent requirements are imposed on the probability of an error in the communication channel, while the «Messi» decoder is more appropriate to use in the presence of restrictions on computational complexity

SPATIAL CHARACTERIZATION OF TELECOMMUNICATION SATELLITES VISIBLE ABOVE THE REPUBLIC OF SERBIA

This paper deals with the general technical, spatial, and temporal characteristics of satellite telecommunications systems. Particular attention was paid to the peculiarities of the territory of the Republic of Serbia in terms of implementation and use of modern satellite telecommunication infrastructure. The overview shows how and on which way to use various satellite telecommunication systems to configure and exploit next-generation networks, especially modern communications such as 5G technology and IoT. Their work cannot be imagined without the high speeds and high frequencies that allow us to transmit a wealth of information - from short messages/news to HD video on a mobile phone. We need either a base station network or in the case of the high seas or areas where the base station system is difficult to imagine, we need satellite communication. The paper presents data that give a numerical and graphical overview of geostationary satellites visible from the territory of the city of Belgrade, depending on the orbital position and the associated angle of azimuth and elevation, which would also be valid for the leading territory of Serbia.

Digital filter for device of determining coordinates of radio signal source in satellite telecommunications systems

Work is devoted research of signal power dependence that will be used in the measurements and noise components of the signal from the digital filter type, filter parameters for various signal-to-noise ratios. The substantiation of the relevance of research is given, which consists in finding the possibility of using digital filters for a device for determining the coordinates of a radio signal source in satellite telecommunications, providing a minimum error in measuring the phase difference. The structure of the system for determining the coordinates of the radio signal source is given. The developed computer model and its description are presented. The researchers are considered for digital recursive band-pass filters of the Butterworth, Chebyshev type 1, Chebyshev type 2, Zolotarev-Cauer type, which are specified using a discrete linear system. Appropriate conclusions are drawn about the applicability of digital filters in the device for determining coordinates. The types of filters are determined and requirements are presented to ensure the minimum error in measuring the phase difference.

Регульований поляризатор на основі квадратного хвилеводу із діафрагмами та штирями

Polarization signal processing is widely used in modern information and telecommunication systems for various purposes. Signal polarization processing is carried out in polarization-adaptive antenna systems. The key element of such systems is transformation devices for polarization processing. They perform the transformation of the types of polarization and separate the different types. The most commonly applied systems are the ones using a single circular polarization or two orthogonal circular polarizations simultaneously.The absence of the need for an accurate angle orientation between the transmitting and receiving antennas to establish communication is one of the basic advantages of this type of polarization. When using antenna systems with linear polarization, signal losses appear due to inconsistency in the orientation of the polarization planes of the transmitting and receiving antennas. This feature of circular polarization is important for satellite and many other telecommunications systems. In such systems it is difficult to maintain a fixed orientation of one antenna relative to the other. In addition, circular polarization is used to communicate with satellites orbiting the direction of the radio link. Regardless of antenna orientation, when using circular polarization, the received signal level is constant. These advantages explain why circular polarized antennas are widely used in radio engineering systems for various purposes. The paper presents the results of the development of a polarization device based on a square waveguide with two posts and two diaphragms in the frequency range from 7,7 to 8,5 GHz. The article contains the results of calculations using the developed mathematical model of the device. In addition, the results of modeling the device using the finite element method are presented for comparison. A comparison was made of the polarization characteristics and the match of the developed polarizer. The created mathematical model makes it possible to effectively analyze the characteristics when changing design parameters. These parameters include the size of the wall of the square waveguide, the heights of the diaphragms and pins, the distance between them, the thickness of the diaphragms and pins. The developed polarizer is suggested for the application in satellite telecommunication and radar systems.

Optimization of a polarizer based on a square waveguide with irises

Antenna systems with polarization signal processing are key element of modern satellite telecommunications systems. In such systems polarization processing is performed by waveguide polarizers. Thus, the development of the design of new polarizers, the creation of new methods for their analysis and optimization are important problems. Waveguide polarizers with irises are the most efficient and technologically advanced in manufacturing. Moreover, they provide wide bandwidths. Optimization of the electromagnetic characteristics of a waveguide polarizer with irises is the goal of the study. To achieve this purpose, we solve the problem to create a new mathematical model, which makes it possible to analyze the influence of the polarizer design parameters on its electromagnetic characteristics. In the investigation a model of a waveguide polarizer with irises was created using the theory of microwave circuits. A new analytical model of such a polarizer has been developed using a general wave scattering matrix. The main characteristics of the waveguide polarizer were determined through the matrix elements. In this work the optimization of characteristics of a polarizer based on a square waveguide with irises has been carried out in Ku-band 10.7–12.8 GHz. The presented mathematical model of such a polarizer allows to take into account the heights of the irises, the distances between them and their thicknesses. The results obtained show that the proposed model is simpler for calculation of the electromagnetic characteristics in comparison with the finite integration technique, which is used to analyze microwave devices for various purposes.

SATELLITE SEGMENT OF NATIONAL INFORMATION INFRASTRUCTURE. APPROACHES TO IMPLEMENTATION

It is proved that the satellite segment is a necessary component of the national information infrastructure. From this position, the state and development trends of satellite telecommunication systems and satellite channel organization technologies are analyzed. It is shown that there are two ways to build a satellite segment: based on the use of leased resources of satellite operators operating in the satellite communications market; based on the resources of the national satellite communications system, which still needs to be created. It is shown that satellite telecommunication systems have a steady tendency to increase the number of spacecraft, until the launch of “heavyˮ satellites with a payload of more than 70 transponders and to increase the frequency resource. The diagram of satellites location density of in orbit is given. In the case of orientation to rent the resources of active spacecraft, the criteria for their selection is indicated. The arc of the geostationary orbit, on which the satellite should be selected, is calculated. For satellites located on this arc, diagrams of equivalent isotropically radiated power values in the C and Ku bands, which they provide in Ukraine, are shown. A list of satellites that you can focus on, recommendations for selection and a list of recommended for the satellite segment is indicated. The technology standards used in payload and methods for organizing satellite communications channels is noticed. To select the parameters of the satellite segment, the results of calculations of the effectiveness of signal-code structures are provided. Approaches to creating a satellite segment of the national information infrastructure are proposed. It is shown that the orientation to the Lybid national satellite does not make sense; a new frequency-orbit resource is required. The types of platforms that can be used on a national satellite are considered.

Spatial characterization of telecommunication satellites visible above the Republic of Serbia

This paper deals with the general technical, spatial, and temporal characteristics of satellite telecommunications systems. Particular attention was paid to the peculiarities of the territory of the Republic of Serbia in terms of implementation and use of modern satellite telecommunication infrastructure. The overview shows how and on which way to use various satellite telecommunication systems to configure and exploit next-generation networks, especially modern communications such as 5G technology and IoT. Their work cannot be imagined without the high speeds and high frequencies that allow us to transmit a wealth of information - from short messages/news to HD video on a mobile phone. We need either a base station network or in the case of the high seas or areas where the base station system is difficult to imagine, we need satellite communication. The paper presents data that give a numerical and graphical overview of geostationary satellites visible from the territory of the city of Belgrade, depending on the orbital position and the associated angle of azimuth and elevation, which would also be valid for the leading territory of Serbia.

MULTIPOSITION TELECOMMUNICATION SYSTEM OF ELECTROMAGNETIC EMISSION INFLUENCE ON SATELLITE BROADBAND LINES OF RADIO COMMUNICATION

The structure of construction of a multiposition system (BS) of electromagnetic radiation influence on satellite broadband radio channels, consisting of synchronously operating spatially spaced low-power transceivers N_ts and having a fully connected topology network (similar to B) . As a result, it is possible to concentrate the radiating power in a given direction. By increasing the base of the transmission system, when its dimensions become comparable to the distance to the object under study, the wave front is no longer planar and the radiating power can be concentrated not only in the direction but also in the distance (focus in a certain area of space). Along with the N_ts collaboration mode, the transceivers of the satellite television telecommunication system can operate autonomously (independently of each other) and alternately, in accordance with the control law, which increases the flexibility of the BS operation. In addition, the use of several simultaneously working emitters can increase the range of BS. Reducing the power level of the signals emitted by individual positions increases the secrecy of the system, since the value of the resulting component of the electric field, determined by the geometric sum of the fields of individual emitters, will be high in a limited area of space, as well as electromagnetic compatibility with other electronic and electronic means one area in the common frequency band. The method of calculation of mutual interference with the sharing of frequencies of the satellite network and the multipoint satellite telecommunication system is presented and a practical experiment will be conducted to block the operation of the terrestrial satellite receiving station by external radio interference. The results of experimental studies have shown that the radiation power of this instance of the microwave blocking device is sufficient to block the operation of the terrestrial satellite receiving station at a distance of up to 30 km, in the presence of direct visibility between the antenna of the blocking device and the satellite receiving transceiver, which can have both a positive and a negative effect on the practical application of a microwave blocking device..

COMPACT KU-BAND IRIS POLARIZERS FOR SATELLITE TELECOMMUNICATION SYSTEMS

In this article, the results of development, optimization, and analysis of new compact iris polarizers based on a square waveguide are presented. The polarization and matching characteristics of the polarizers with the different number of irises were optimized within the operating Ku-band 10.7-12.8 GHz. The numerical simulations and optimization of waveguide polarizer characteristics were carried out using a finite integration technique. The improvement of the performance of optimal polarizers and evolution of their dimensions was investigated for the polarizers with a number of irises ranging from 2 to 5. The best characteristics among the analyzed waveguide iris polarizers are achieved for the polarizer with 5 irises. Optimized compact square waveguide polarizer with 5 irises shows efficient polarization and matching performance in the whole operating Ku-band 10.7-12.8 GHz. Developed compact iris polarizers can be widely applied in modern dual-polarization antennas for satellite telecommunication systems.

MOBILE SATELLITE COMMUNICATION SYSTEM WITH PASSIVE TERMINALS BASED ON MODULATING RETRO-REFLECTORS

In this work, a qualitative and quantitative comparison of satellite mobile communications systems with various altitudes of the orbits of spacecraft was carried out. A study of the conditions for the spacecraft to be located in the visibility range of the ground terminal and an analysis of the time spent by the satellite in the visibility zone depending on the height of the orbit was made. According to the results of this analysis and taking into account the fact that the low orbit area around the Earth is very densely filled with artificial satellites and space debris, it can be concluded that it is advisable to increase the radius of the orbit of telecommunication satellites. At the same time the geostationary orbit, which has obvious advantages in terms of coverage, is also quite densely filled with spacecraft, and is very high for the efficient operation of low-power mobile ground terminals. Taking into account these features, it is concluded that the use of medium-height orbits for telecommunication satellite systems is promising for which global coverage of the Earth’s surface can be achieved using several dozen satellites. In addition, the distance to the Earth’s surface will be small enough to provide a high signal-to-noise ratio and, as a result, the system will provide a high bitrate. A computer simulation of the operation of a satellite telecommunication system was carried out for a different number of spacecraft and various parameters of their orbits in order to determine the conditions for achieving global coverage. This simulation confirms the conclusions regarding the feasibility of using medium orbits. The concept of using passive terminals based on modulating retroreflectors was proposed. It means the reflection of a satellite signal by a ground terminal without emitting its own electromagnetic energy. The energy of the terminals is spent only on the modulation of the reflected signal. This approach will significantly reduce the energy consumption of ground terminals and thereby increase mobility. It is proposed to carry out phase and polarization modulation of the signal using liquid crystals or metamaterials.

Identification of possible Δ14C anomalies since 14 ka BP: A computational intelligence approach

Rapid increments in the concentration of the radiocarbon in the atmosphere (Δ14C) have been identified in the years 774–775 CE and 993–994 CE (Miyake events) using annual measurements on known-age tree-rings. The level of cosmic radiation implied by such increases could cause the failure of satellite telecommunication systems, and thus, there is a need to model and predict them. In this work, we investigated several intelligent computational methods to identify similar events in the past. We apply state-of-the-art pattern matching techniques as well as feature representation, a procedure that typically is used in machine learning and classification. To validate our findings, we used as ground truth the two confirmed Miyake events, and several other dates that have been proposed in the literature. We show that some of the methods used in this study successfully identify most of the ground truth events (~1% false positive rate at 75% true positive rate). Our results show that computational methods can be used to identify comparable patterns of interest and hence potentially uncover sudden increments of Δ14C in the past.