Low Orbit Satellite Communication Research Articles

A Single Layer Low Axial Ratio Circularly Polarized Planar Wide-Angle Scanning Phased Array

This paper proposes a circularly polarized planar wide-angle scanning phased array radar. The structure of the proposed array element is a windmill-type patch with an octagon-shaped series power divider. The proposed array exhibits a low axial ratio because the element has a wide 3-dB axial ratio beamwidth and the array topology uses the sequential rotation technique. Test results show that the proposed 8 × 8 uniform planar array can realize two-dimensional circularly polarized scanning from −60° to +60° in the working band of 3.43–3.48 GHz. The coverage gains of θ = ±60° are about 3 dB lower than the gain when the main beam points at θ = 0°. Moreover, in the scanning mentioned above airspace, the scanning beam axial ratio is below 0.5 dB in the xz-plane (φ = 0°) and yz-plane (φ = 90°) and below 1.4 dB in the D-plane (φ = 45°). Another notable feature is the single-layer structure, and its profile is only 0.08λ0 at the center wavelength. This good low- axial ratio and low-profile characteristics make the proposed array potentially applicable to low-orbit satellite communications.

Free-space optical (FSO) feeder link planning in space-ground integrated optical networks (SGIONs): trade off throughput and dynamics.

The low-orbit satellite communication can provide users with low-delay and ultra-wideband communication services worldwide. By the wide available bandwidth and immunity to interference, free-space optical (FSO) feeder links are presented as an ideal alternative to radio frequency (RF) feeder links for satellite-to-ground backhaul, and the space-ground integrated optical network (SGION) is gradually formed by using FSO feeder links to integrate the low-orbit satellites and the terrestrial optical network (TON) for backhaul services. The propagation channel characteristics of FSO feeder links vary significantly during low-orbit satellite passes, and atmospheric turbulence causes serious scintillation in FSO feeder links at low elevations, increasing link budget and restricting link capacity. Limiting the observation range of optical ground stations (OGSs) to the high elevation area can establish high-capacity feeder links to improve SGION's throughput, but inevitably increase the network dynamics and reduce the satellite visibility. This paper trades off SGION's throughput and dynamics by planning FSO feeder link handover and capacity adjustment. Two baseline schemes and the feeder link handover and capacity adjustment scheme based on non-dominated sorting genetic algorithm (NSGA-FLHCA) are proposed. By finding the Pareto edge of the multi-objective optimization problem, NSGA-FLPCA is more effective in improving network throughput and reducing network dynamics compared with two baselines.

Analysis of the influence of natural and climatic conditions in the Arctic and the Far North on the stability of air traffic

The analysis of the influence of natural and climatic conditions of the Arctic and Far North on the stability of air connection is investigated in this article. The provision of year-round mainline, interregional and regional air transportation is associated with the complexity of controlling the flight path of aircraft in extreme Arctic conditions. For the Arctic zone, the possibility of using a constellation of low-orbit satellite communication systems is being considered for transmitting data on the position of an aircraft to a control tower located on the ground. In this case, data transmission is possible both using GSM communication through ground stations, and using inter-satellite communication lines.

Adaptive Authentication Protocol Based on Zero-Knowledge Proof

Authentication protocols are expanding their application scope in wireless information systems, among which are low-orbit satellite communication systems (LOSCS) for the OneWeb space Internet, automatic object identification systems using RFID, the Internet of Things, intelligent transportation systems (ITS), Vehicular Ad Hoc Network (VANET). This is due to the fact that authentication protocols effectively resist a number of attacks on wireless data transmission channels in these systems. The main disadvantage of most authentication protocols is the use of symmetric and asymmetric encryption systems to ensure high cryptographic strength. As a result, there is a problem in delivering keys to the sides of the prover and the verifier. At the same time, compromising of keys will lead to a decrease in the level of protection of the transmitted data. Zero-knowledge authentication protocols (ZKAP) are able to eliminate this disadvantage. However, most of these protocols use multiple rounds to authenticate the prover. Therefore, ZKAP, which has minimal time costs, is developed in the article. A scheme for adapting protocol parameters has been developed in this protocol to increase its efficiency. Reductions in the level of confidentiality allow us to reduce the time spent on the execution of the authentication protocol. This increases the volume of information traffic. At the same time, an increase in the confidentiality of the protocol entails an increase in the time needed for authentication of the prover, which reduces the volume of information traffic. The FPGA Artix-7 xc7a12ticsg325-1L was used to estimate the time spent implementing the adaptive ZKAP protocol. Testing was performed for 32- and 64-bit adaptive authentication protocols.

Potential key challenges for terahertz communication systems

The vision of 6G communications is an improved performance of the data rate and latency limitations and permit ubiquitous connectivity. In addition, 6G communications will adopt a novel strategy. Terahertz (THz) waves will characterize 6G networks, due to 6G will integrate terrestrial wireless mobile communication, geostationary and medium and low orbit satellite communication and short distance direct communication technologies, as well as integrate communication, computing, and navigation. This study discusses the key challenges of THz waves, including path losses which is considered the main challenge; transceiver architectures and THz signal generators; environment of THz with network architecture and 3D communications; finally, Safety and health issues.

Анализ применимости стандартных протоколов динамической маршрутизации в сетях спутниковой связи на основе низкоорбитальных космических аппаратов

One of the key components of communication networks, which determines the principles of their operation, are traffic routing protocols. The purpose of this article is to consider the possibility of using widely used dynamic routing protocols in LEO satellite communication systems. Based on the available publications, the analysis of the initial data was carried out and the conditions for the functioning of routing protocols in low-orbit satellite communication systems, as well as the basic requirements for such protocols, were formulated. The analysis of the functioning of the dynamic routing protocols in the given conditions is carried out. The disadvantages of the considered protocols are highlighted and characterized. The main conclusion of the article is the inexpediency of using the considered protocols in low-orbit satellite communication networks due to the high resource requirements and the insufficient speed of propagation of changes. The results can be used to substantiate technical solutions in the design of low-orbit satellite communication networks.

Subscriber and inter-satellite paths in LEO communications networks

The purpose of the study is to propose and substantiate technical solutions for inter-satellite and subscriber paths of loworbit communication networks. There is a prospect of commercial use of such networks; therefore, the current stage of low-orbit satellite communications development is characterized by an increase in efforts to put the projects into practice. As part of the study, solutions for inter-satellite paths (ISP) in low-orbit communication systems and solutions that increase the capacity of their subscriber paths are considered. It is noted that ISPs can be built on the basis of radio and optical bands equipment. In this regard, the advantages and disadvantages of each case are considered. The expediency of constructing subscriber paths based on radio band equipment and the preference of constructing ISP based on optical band equipment are substantiated. The relationship between the feasibility of increasing the capacity of subscriber paths and the capabilities of ISP in terms of reliability and bandwidth is established.

INNOVATIVE METHOD OF SATELLITE COMMUNICATION

The technical aspects of the main promising projects in the segments of medium and low-orbit satellite communication systems are considered, as well as the project of the domestic low-orbit information and telecommunications system using the terahertz range, which is based on the use of satellite platforms of the micro- and nanosatellite class and the distribution of functional blocks of complex satellite payloads more high-end on multiple functionally related satellites. The proposed system of low-orbit satellite communications represents the groupings of low-orbit spacecraft (LEO-system) with the architecture of a "distributed satellite", which include the groupings of the root (leading) satellites and satellite repeaters (slaves). Root satellites are interconnected in a ring network by high-speed links between the satellites. The geometric size of the “distributed satellite” is the area around the root satellite with a radius of about 1 km. The combination of beams, which are formed by the repeater satellites, make up the service area of the LEO system. The requirements for the integrated service area of the LEO system (geographical service area) determine the requirements for the number of distributed satellites in the system as a whole. In the proposed system to reduce mutual interference between the grouping of the root (leading) satellites and repeater satellites (slaves) and, accordingly, minimizing distortions of the information signal when implementing inter-satellite communication, this line (radio channel) was created in an unlicensed frequency (e.g., in the terahertz 140 GHz) range. In addition, it additionally allows you to minimize the size of the antennas of such a broadband channel and simplify the operation of these satellite systems.

G-BDP-ADC Model for Effectiveness Evaluation of Low Orbit Satellite Communication System in the Context of Poor Information

Effectiveness evaluation of LEO satellite communication system can not only guide the optimization of constellation program,but also play an important role in the stage of system design. In order to ensure the accuracy of the evaluation results, it is necessary to consider the impact of uncertain information on effectiveness evaluation, whether it is due to poor information or complex system.In order to solve this problem, this paper introduces birth and death process into satellite communication system.Firstly, according to the limit distribution of grey birth and death process with continuous time and limited state, we establish the availability model of the system.Then, the Kolmogorov forward equation is used to characterize the dependability of the system during operation.After that, a capability evaluation index system based on “four domains” is constructed. The attribute values of the index are unified into generalized standard interval grey numbers, and the weight allocation model of GSIGN-AHP-ME is established.The system capability is calculated according to the full probability formula.Subsequently,taking constellation X as an example, the system effectiveness is obtained by using the G-BDP-ADC model constructed in this paper.Finally, by comparing with the fuzzy evaluation method, it shows that the G-BDP-ADC model constructed in this paper is better than the fuzzy evaluation method, and can describe the LEO satellite communication system in the context of poor information more appropriately.

СОЗДАНИЕ АРХИТЕКТУРЫ «РАСПРЕДЕЛЕННОГО СПУТНИКА» ДЛЯ НИЗКООРБИТАЛЬНЫХ ИНФОРМАЦИОННО-ТЕЛЕКОММУНИКАЦИОННЫХ СИСТЕМ НА ОСНОВЕ ГРУППИРОВКИ МИКРО- И НАНОСПУТНИКОВ

Presented are the results of an analysis of the growing interest in the use of low Earth orbits (up to 1500 km high) for the introduction and development of the Internet of things (Internet of Things - IoT). Industrial Internet of things (Industrial Internet of Things-IIoT). Internet of things for remote areas (Remote Internet of Things - RioT, for the purposes of scientific research and economic use of natural resources, control of the development and operation of infrastructure projects, the operation of territorially distributed industrial production, transport infrastructure. Factors significantly limiting the further introduction of micro and nano satellites are given. The authors proposed to resolve this contradiction on the basis of the developed concept of creating the architecture of a "distributed satellite". As an example, the article considers possible applications of the distributed satellite architecture in two segments of the space information systems market: remote sensing of the Earth and telecommunication systems. The application of the "distributed satellite" in radar systems with synthesized aperture (SAR-system) was considered taking into account the requirements of the operators of satellite SAR-systems and consumers of their information. It is shown. that the use of the "distributed satellite" architecture in SAR-systems also makes it possible to realize the technology of multi-static radar with a "soft" interference base (from 200 m to 1 km). The scheme of organization and interaction of the "distributed satellite" in the satellite-transmitter on the platform of the micro satellite, which is the core of the satellite cluster, and several satellites-receivers on the cube-sat platform is presented. The functions performed by the satellite-transmitter, the inter-satellite radio link and the satellite-receiver are considered in detail. The work of the "distributed satellite" is illustrated by the presented structural diagram of the SAR-system for remote sensing of the Earth, a version of the architecture of the low-orbit satellite communication system and the scheme for constructing a satellite system for the provision of IoT services. In conclusion, it is noted that the architecture of the "distributed satellite" makes it possible to effectively use satellites of the class of micro/nano satellite (cube-sat) to create complex space-based information and telecommunication systems

PERSPECTIVES OF ON-BOARD PACKET ROUTING IN LOW-ORBIT COMMUNICATION NETWORKS

We have reviewed low-orbit satellite communication system with inter-satellite paths. The issues related to packet delivery arising from failures of the satellites in the network have been identified and analyzed.

Применение помехоустойчивого протокола аутентификации космического аппарата для низкоорбитальной системы спутниковой связи

Применение помехоустойчивого протокола аутентификации космического аппарата для низкоорбитальной системы спутниковой связи

Increasing of Low Orbit Satellite Communications Efficiency

Increasing of Low Orbit Satellite Communications Efficiency