Inter-satellite Communication Research Articles

基于中短距离星间链路的可见光通信及性能分析

To meet constraints on size, weight, and power consumption in small satellite platforms and explore alternative solutions for radio frequency and laser-based communication in medium- and short-distance inter-satellite links, this study explores the feasibility of visible-light communication (VLC) based medium- and short-distance inter-satellite communication in multi-satellite networks. Using the satellite tool kit (STK), the binary star formation flying configuration is constructed, background-light noise introduced by the sun and stars is quantitatively analyzed, and a medium- and short-range inter-satellite VLC link model is constructed. Then, to improve the link capacity and reliability, the VLC link is further developed into a single-input multi-output VLC (SIMO-VLC) system. The influences of different diversity merging algorithms on the link's performance are evaluated by numerical simulation. Simulation results show that the stray light power introduced by solar radiation is below 10 μW throughout most of the time period, and the background light power introduced from the ground is reduced by 75%. In order to achieve a data transmission rate of 112.5 Mbit/s and a bit error rate of 1×10-6 within 20 km, the light power required by the system is at least 4.55 W. Compared with the single-input single-output system, the SIMO-based diversity detection scheme can achieve better performance, and the required transmission power and communication distance are effectively improved with the increase of the receiving branch, which can provide a reference for the design of VLC-based inter-satellite links and extending their outdoor application scenarios. © 2019, Chinese Lasers Press. All right reserved.

Role of Millimeter Waves in Satellite Communication


 
 
 Millimeter Wave satellite communications are discussed with only modest site separation and switched diversity .Various aspects of Millimeter Wave communication link at 35 GHz ,60 GHz and 94 Ghz frequencies for satellite applications are discussed in the paper. Link calculations are carried out and possible hardware configurations are sketched out briefly in respect of Ground Satellite and Inter Satellite Communications Links.
 
 

Intersatellite Communication System Based on Visible Light

Future space missions will be driven by factors such as the need for reduced cost of spacecraft without diminished performance, new services, and capabilities including reconfigurability, autonomous operations, target observation with improved resolution and servicing (or proximity) operations. Small satellites, deployed as a sensor network in space, can through intersatellite communication (ISC) enable the realization of these future goals. Developing the communication subsystem that can facilitate ISC within this distributed network of small satellites require a complex range of design tradeoffs. For small satellites, the general design parameters that are to be optimized for ISC are size, mass, and power, as well as cost (SMaP-C). Novel and efficient design techniques for implementing the communication subsystem are crucial for building multiple small satellite networks with capability for achieving significant data-rates along the intersatellite links (ISLs). In this paper, we propose an alternative approach to radio frequency and laser ISLs for ISC among small satellites deployed as a sensor network in low earth orbit. For short to medium range ISLs, we present an LED-based visible light communication (VLC) system that addresses the SMaP constraints, including capability for achieving significant data rates. Our research is focused on the development of the physical layer for pico-/nano class of satellites with prime consideration for the impact of solar background illumination on link performance. We develop an analytical model of the intersatellite link (ISL) in MATLAB and evaluate its feasibility and performance for different intensity modulation and direct detection schemes. Using a transmitted optical power of 4 W and digital pulse interval modulation, a receiver bandwidth requirement of 3.5 MHz is needed to achieve a data rate of 2.0 Mbits/s over a moderate link distance of 0.5 km at a BER of 10−6.

The Optimization Design of Sub-Regions Scanning and Vibration Analysis for Beaconless Spatial Acquisition in the Inter-Satellite Laser Communication System

We mainly report an efficient approach to optimize the design of beaconless spatial laser acquisition. In order to analyze the influence of vibration environment on the beaconless spatial acquisition, a demonstration of an efficient method will be presented to simulate the level of satellite platform vibration. An important power spectral density (PSD) model of satellite platform vibration used by the European Space Agency is introduced. Then through LABVIEW, a simulated vibration waveform is generated, and the simulated PSD has a basic consistency with the in-orbit measurement spectral line, referring to the design of the filter, generating the Gaussian white noise sequence, filtering the pseudorandom signal and the whole processing procedure of parameter matching. The variation interval of the vibration amplitude is from −100 to 40 μrad. Then, the model of beaconless acquisition is proposed, which uses the spiral scan pattern, laser with a divergence angle of 80 μrad scan in an uncertainty cone (UC), and also the scan coupled with the simulated vibration is given. Through the beaconless acquisition program, the vibration is suppressed between −10.7 and 5.9 μrad; when the overlap factor is selected as 10%, it does not produce any leakage scanning area. It can be used for a wide variety of platforms. This new method will be good for analysis and test of beaconless spatial acquisition algorithm. Finally, the description of acquisition duration, which mainly includes the fast steering mirror spiral scan and the mechanical rotary table step scan, is introduced. And the corresponding optimal selection method of sub-region is proposed; the design of 1.6-mrad scanning pattern with 7 × 7 sub-regions in the 8-mrad acquisition UC is given. Through the actual measurement, the acquisition time is 18.21 s, the tracking error is better than 0.4 μrad.

A high gain S-band slot antenna with MSS for CubeSat

Cube satellites, aka CubeSats, are a class of tiny satellites that have become popular for space programs. This is because they can be built relatively cheaply using commercial off-the-shelf components. Moreover, CubeSats can communicate with each other, and assemble into swarms to carry out different functions: e.g., wide area measurements and sensing. Swarms of CubeSats also have the effect of increasing the contact period with ground stations allowing for a longer communications window. These capabilities require CubeSats to be equipped with an efficient, high gain, small antenna to facilitate cross-link or inter-satellite communications. Henceforth, this paper presents a high gain coplanar waveguide (CPW)–fed slot antenna for CubeSats. A key feature is the use of a metasurface superstrate structure (MSS) to significantly improve gain and reduce back-lobe emissions. This also has the advantage of minimizing interference to components inside a CubeSat. We have comprehensively evaluated the antenna using the high-frequency simulator structure (HFSS) as well as a carrying out testing on a 3 U (10 × 10 × 30 cm3) CubeSat platform. We have studied the effect of MSS element sets and their position and the effect of a 3-U CubeSat body on the performance of the proposed antenna. The experimental results confirm that our antenna achieves a return loss of 21.5 dB and a fractional impedance bandwidth (BW) of 55.91% with S11 ≤ 10 dB and has a simulated and measured gains of 9.71 and 8.8 dBi respectively at the desired frequency of 2.45 GHz. In contrast, amongst all previous S-band planar antennas that are suitable for CubeSats, the best gain is only 5.96 dB at 2.45 GHz.

Low-Power SDR Design on an FPGA for Intersatellite Communications

Small satellite systems make space missions for communication, navigation, and scientific research more realizable and diversified. Small satellites flying in large cluster or constellation formation as a network can provide an economical access to accomplish more complex missions, such as distributed computation, high-resolution imaging, and spacecraft maintenance. An increasing number of satellites operating on lower earth orbit for complex missions require a wireless communication system that is both reliable and flexible. This paper presents a complete software-defined radio (SDR) model for intersatellite communications (ISCs) and its implementation on a field-programmable gate array (FPGA). The proposed SDR for transmitter and receiver only has a power consumption of 2.1 and 3.2 W, respectively, which is suitable for power-limited small satellite systems. Algorithms and parameters of each block are optimized aiming at reducing hardware resource utilization. A low-density parity-check code constructed by the Euclidean geometry method is adopted as the channel code for forward error correction. Implementations of the synchronization, demodulation, and decoding algorithms are optimized for hardware efficiency. The low-power SDR designs are implemented on an FPGA-based experimental platform and successful demonstrated by over-the-air transmissions.

Transparent intersatellite optical wireless communication link with double sideband-suppressed carrier modulation and coherent homodyne detection

In this paper, we present an intersatellite optical wireless communication (IsOWC) link with double sideband-suppressed carrier (DSB-SC) modulation and coherent homodyne detection (CD), which enables transparent transport of multiband radio frequency (RF) signals. The performance of transparent multiband IsOWC link employing DSB-SC/CD and phase modulation with CD (PM/CD) is investigated. The theoretical model considers the finite extinction ratio (ER) of a Mach-Zehnder modulator (MZM) and the saturation property of an optical booster amplifier. The expressions of RF gain, noise figure (NF) and third-order spurious-free dynamic range (SFDR) are derived considering the third-order intermodulation product and amplifier spontaneous emission noise for both architectures. Numerical results for RF gain, NF, and third-order SFDR are given for demonstration. Results indicate that DSB-SC/CD can provide higher linearity and better sensitivity than PM/CD. The performance of the DSB-SC/CD scheme is obviously influenced by the ER of MZM. The gain of the optical preamplifier and the power of a local oscillator optical signal should be optimized to obtain satisfactory performance.

ТЕРАГЕРЦОВІ ТЕХНОЛОГІЇ В ТЕЛЕКОМУНІКАЦІЙНИХ СИСТЕМАХ. ЧАСТИНА 2. ДОСЛІДЖЕННЯ ТА МОДЕЛЮВАННЯ ПЕРЕДАВАННЯ ТЕЛЕВІЗІЙНИХ СИГНАЛІВ СТАНДАРТУ DVB-C І ІМПУЛЬСНОГО НАДШИРОКОСМУГОВОГО СИГНАЛУ РАДІОЛІНІЄЮ ТЕРАГЕРЦОВОГО ДІАПАЗОНУ

The laboratory testbed of a digital simplex radio-relay system of the terahertz range has been studied for the first time in practical terms. It consists of the receiver and transmitter parts of 130÷134 GHz frequency range and a digital modem with a channel data transmission of up to 1200 Mbps for a communication point-to-point distance under normal conditions within 1 km. It is shown that the proposed telecommunication system, which implements the concept of the creation of software-defined radio systems based on Wi-Fi technology, can be highly productive in the next generation mobile communication networks providing the appropriate transmission speeds, reliability, and security. It is studied the parameters of multichannel digital TV signal DVB-C standard when it is transmitted through the testbed of the transmitter and receiver parts of 130 GHz band. The results of the research showed that the application of lower part of terahertz frequency band (130 GHz) with a bandwidth of 24 MHz allows the transmission of three DVB-C television broadcasting channels with a total transport speed of 125 Mbit/s with a high subjective quality of TV programs. The results of the simulation of impulse ultrawideband (IR-UWB) signal transmission by the wireless link of terahertz band are presented. The results of researches of changes of IR-UWB Gaussian monocycle in the transmitter part and its reception by the receiver part of 130.4÷131.5 GHz terahertz band are presented for the first time. On the basis of the results of the research, the requirements for parameters of terahertz wireless link are formulated to ensure acceptable quality of ultrawideband impulse signals receiving. Development of the transmitter and receiver parts of radio relay system of the terahertz range has no direct current analogs in Ukraine. It can provide a significant breakthrough in the development of the telecommunications industry. The obtained research results will also contribute to the development of telecommunications-related industries, in particular: radio astronomy, inter-satellite communication, radar systems, medicine, etc.

Pointing and tracking errors due to low-frequency deformation in inter-satellite laser communication

ABSTRACTA Gaussian random-phase screen (GRPS) model is proposed to represent the low-frequency wave-front deformation in inter-satellite laser-communication links. The model is used to investigate mutual-alignment errors comprising pointing and tracking errors caused by the low-frequency deformation. Theoretical analysis and numerical simulation show that the GRPS root-mean-square (RMS) value, pointing error, and tracking error increase with the amplitude factor and the scale length in the model. The expectation of RMS increases in the form of a linear function with and increases in the form of a cubic function with . The expectations of the pointing and tracking errors increase with increases in the expected values for and . For a specific pointing error or tracking error, the 99.5% confidence interval of the RMS of the low-frequency wave-front deformation is provided. From this confidence interval, the lower limit of the processing precision of optical antennas corresponding to certain mutual-alignment errors can be predicted. These conclusions are expected to be instrumental in designing inter-satellite laser-communication systems.

Radiation-induced mismatch effect on performances of space chaos laser communication systems.

Chaotic modulation serves as an excellent scheme to enhance the confidentiality of space laser communication systems. Considering radiation and intensity scintillation, we establish bit error rate (BER) computation models for both an inter-satellite chaos laser communication system and a satellite-to-ground chaos laser communication system. Based on such models, numerical simulations are conducted to investigate the mismatch effect on BER performance of these two typical systems. For an inter-satellite system, radiation can induce great parameter mismatches. For a satellite-to-ground system, the BER only slightly rises due to intensity scintillation being a more dominant deterioration effect than radiation. Our work has good reference value for the practical design of space chaos laser communication systems.

Approach for recognizing and tracking beacon in inter-satellite optical communication based on optical flow method.

In inter-satellite laser communication systems, accurate positioning of the beacon is essential for establishing a steady laser communication link. For inter-satellite optical communication, the main factor affecting the acquisition and tracking of the beacon is the background noise, such as stellar background light. In this study, we considered the effect of the background noise on a beacon in inter-satellite optical communication and proposed a new recognition algorithm for the beacon, which uses the optical flow vector obtained from the image data. We verified the feasibility of this method by performing simulation analysis and experiments. Both simulation and experiments showed that the new algorithm could accurately obtain the position of the centroid of the beacon under the effect of the background light. Furthermore, considering the identification probability of a light spot through the background light, the locating accuracy of the new algorithm was higher than that of the conventional gray centroid algorithm. Therefore, this new approach would be beneficial for the design of satellite-to-ground optical communication systems.

Inter-Satellite Communication for LEO CubeSat Network: QoS Parameters and Feasibility of Massive MIMO

This paper evaluates inter-satellite communication for a low earth orbit CubeSat network. This paper consists of two parts: determination and estimation of quality of service (QoS) parameters and evaluation of the feasibility of a Massive Multiple Input Multiple Output (MIMO) system for inter-satellite links. CubeSats are low-cost and small satellites that were initially designed by students during the educational process but are now launched for conducting space research and for commercial use. Recently, some companies and research studies promoted CubeSats to build a wireless communication networks for different proposes, such as earth observation, weather forecasting, providing access to the internet, internet of things and machine to machine services. The main distinguishing features of a CubeSat network include low-cost and fast deployment with a consequent advantage: the possibility to build a large network (hundreds of spacecraft) with limited resources. However, due to the limited size and function of CubeSats, the feasibility of a CubeSat network with inter-satellite links is debatable. In this paper, we investigate the QoS parameters for an inter-satellite link and factors affecting it. The theoretical design with a constructive drawing of massive MIMO has been made. The possibility and time duration of inter-satellite communication has been calculated for three different cases using real data and including Massive MIMO. The simulation of orbit movements for groups of CubeSats has been made. The correlation between relative positions of satellites in orbits, parameters of communication channels and the QoS was determined. The feasibility of massive MIMO for CubeSat communications has been estimated. Based on simulation results, suggestions and possible technical and non-technical solutions were highlighted together with future studies and simulations.

Homodyne coherent optical receiver for intersatellite communication.

For increasing the data rate and reducing the power consumption in satellite communication systems, free-space optical communication technology has been verified as an attractive alternative to traditional radiofrequency communication systems. In this study, a high-sensitivity homodyne coherent optical receiver was demonstrated. A sensitivity of -59.2 dBm was achieved with an unencoded bit-error rate below 10-3 at a bit rate of 1Gbps (9.4photons/bit does not include any overhead for forward error correction). To achieve homodyne detection, a modified decision-driven Costas optical phase-locked loop and a digital control algorithm were used to suppress the phase error and track the Doppler shift. Test experiments show that the receiver sensitivity penalty caused by the phase error is approximately 1dB and that the receiver can track a Doppler shift at the speed of 100MHz/s. Test experiments demonstrate that the receiver has a robust adaptive capacity to received-power fluctuation. The theoretical analysis and experimental results are presented in this paper.

Optimization of high speed and long haul inter-satellite communication link by incorporating differential phase shift key and orthogonal frequency division multiplexing scheme

Inter-Satellite optical wireless communication (Is-OWC) link plays significant role for transmission of data between the satellites in the space. In this work, 10 Gbps of data is transmitted over 20,000 km Is-OWC link by incorporating differential phase shift key (DPSK) modulation and orthogonal frequency division multiplexing scheme. Signal to noise ratio (SNR), total received power, constellations diagram and radio frequency spectrums are used as key metrics to evaluate the performance of proposed Is-OWC-DPSK communication system. Furthermore, the effects of receiving pointing error for proposed IS-OWC-DPSK communication system are also analysed.

Performance analysis of mode division multiplexing IS-OWC system using Manchester, DPSK and DQPSK modulation techniques

In this work, a high capacity mode division multiplexing (MDM) based Inter-Satellite Optical Wireless system is presented. In order to increase capacity of the system, 64 linearly polarized modes are incorporated in the system. The proposed MDM Inter-Satellite Optical Wireless Communication system has been designed using various modulation techniques such as Manchester, DPSK and DQPSK at the different distances of 750–3750 km and data rates of 10, 20 and 40 Gbps. Results have been compared on the basis of Eye Diagrams, Q-factor as well as minimum Bit Error rate. The comparative analysis shows at the bit rate of 10 Gbps, DQPSK modulation technique provides highest Quality factor of 32.01 followed by DPSK and Manchester Modulation. DQPSK Modulation technique shows best performance till 40 Gbps and Manchester shows least. It is also observed that on increasing bit rates from 10 Gbps to 40 Gbps, Quality factor degrades. Proposed MDM IS-OWC system is reliable to use, flexible, cost effective and useful for long distance communication.

Performance Estimation of Advanced Intensity Modulation Formats Using Hybrid SAC-OCDMA through IsOWC Channel

Abstract Spectral amplitude coding optical code division multiple access (SAC-OCDMA) is one of the most important multiplexing schemes of OCDMA that has turned out to be a stimulating investigating area in optical communication due to its increased privacy, network capacity and its flexibility in allocating the channels and asynchronous environment. On the other hand, Inter-satellite optical wireless communication (IsOWC) which is a favorable area of research in optical communication is useful for bursty transmissions and long-distance communications. In this paper, we have designed a hybrid SAC-OCDMA system through IsOWC channel using ZCC code for advanced intensity modulation formats (CSRZ, Db, and AMI). The investigation is done for four users at a bit rate of 40(4×10) Gb/s using a direct detection technique. Further, on comparing the proposed system using advanced intensity modulation formats, the result shows that system using CSRZ format is better in terms of BER, Q-factor, SNR and the eye diagram with respect to AMI and Db.

Differential phase-shift keying heterodyne coherent detection with local oscillation enhancement

In the field of intersatellite laser communication, there are two high-sensitivity demodulation methods: binary phase-shift keying (BPSK) coherent detection and differential phase-shift keying (DPSK) coherent detection. After taking into account the advantages and disadvantages of BPSK and DPSK, a DPSK heterodyne coherent detection scheme with local oscillation enhancement is proposed. The structure and the principles of this detection system are described, and the theoretical deduction is presented. Moreover, an experimental setup was constructed to test the proposed detection scheme. The offline processing procedure and results are presented. This scheme has potential applications in high-speed intersatellite laser communication.

Development of a ROF-based System Using DQPSK through IsOWC Channel for Long Haul Data Rate Applications

Abstract In order to achieve large capacity inter-satellite communication, optical wireless communication (OWC) is emerging as a promising area of research amongst the academic and research groups. While radio over fiber (ROF) and advanced modulation technique is considered to be a key enabling technology in the development of OWC based access networks for high-speed data transmission. This paper has proposed a novel ROF based system model using OWC for long haul high data rate applications. This system is designed using differential quadrature phase shift keying (DQPSK) through inter-satellite optical wireless communication (IsOWC) channel. The verification of the performance is performed at bit rates of 100 and 200 Gbps over a space distance range up to 1000 to 50000 km under different transmitted power. The simulative investigation has been carried out in terms of important parameters like BER, Q-factor and eye diagrams.

Study of Inter-Satellite Optical Wireless Communication System with different Modulation Techniques

Study of Inter-Satellite Optical Wireless Communication System with different Modulation Techniques

Interplanetary CubeSats for asteroid exploration: Mission analysis and design

Recent advances in CubeSats technology are leading the transition from purely education tools to actual scientific missions. The small volumes and masses, the versatile purpose, as well as the fast development time associated with a potential high return-to-cost ratio are at the origin of the increasing number of new mission proposals, also beyond low Earth orbit (LEO). The purpose of this study is to assess the CubeSats ability to complement an interplanetary scientific mission. The proposed AIDA (Asteroid Impact and Deflection Assessment) mission, an ESA/NASA joint effort to demonstrate the kinetic impact technique to change the motion of an asteroid in space, has been selected as case study, having a mission context particularly suitable in showing CubeSats supporting capabilities. The feasibility study of a mission involving the use of CubeSats as secondaries for technology demonstration and science purposes was performed. Mission objectives and requirements were defined, followed by the development of concepts of operations and mission architectures proposals. Eventually, multiple trade-off tools were adopted to define the proposed mission baseline, which involves the deployment of two 3U CubeSats performing a detachment to achieve the final configuration of one 2U and four 1U CubeSats. The scientific campaign conducted by the CubeSats includes gravitational and magnetic field mapping, on-surface chemical-physical measurements via multiple wide chip-size-sensor nets deployed from orbit, on-surface seismic measurements via landing of the 2U CubeSat, direct observation of the impact from multiple viewpoints and evaluation of the asteroid's orbit deflection due to the impact. The mission proposed involves also some important technological demonstrators. The S-iEPS (Scalable-ion Electrospray Propulsion System) has been considered as propulsion system, while a potential landing system has been proposed to achieve the soft touchdown of the 2U CubeSat. Finally, an inter-satellite communication link via laser has been included as main communication system. The proposed mission baseline has shown that CubeSats can be successfully integrated as multi-platform systems to provide useful support to interplanetary missions. This solution may enable the capability to acquire more detailed information with the possibility to combine them to obtain better results with respect to single-platform systems. The proposed mission concept represents a valuable low-cost piggyback solution adaptable to several mission contexts, with a potential high return and a remarkable attitude for the implementation and testing of new technologies and operations. In this context, this study provides a useful framework for the design and development of interplanetary CubeSats missions.