Communication Satellite Payloads Research Articles

Satellite Communication Payload Based on Microwave Photonics: Benefits, Architecture, and Technologies

Satellite Communication Payload Based on Microwave Photonics: Benefits, Architecture, and Technologies

Chip‐Based Microwave Photonic Payload Repeater for High Throughput Satellites

AbstractHigh‐throughput satellite (HTS) is an ideal way to realize cross‐regional massive, multifaceted digital exchange services, and it requires a signal processing module that can be massively multiplexed and has high flexibility. Due to the limitations of the frequency characteristics, microwave integrated circuits are difficult to meet this requirement. One solution to this problem is photonic integrated circuits (PICs). However, full‐size PIC satellite payloads containing main optoelectronic components are extremely challenging to implement on monolithic or hybrid integrated platforms. Here, the study demonstrates a hybrid integrated on‐chip microwave‐photonic satellite repeater with large‐scale multiplexing potential and high flexibility. This is a demonstration of a hybrid integration of a InP/Si3N4 external cavity laser, arrayed InP modulators, and semiconductor optical amplifiers (SOAs), as well as multifunctional Si3N4 signal processors, to fulfill a 1 × 4 Ka‐band repeater module with on‐chip arrayed frequency down‐conversion and outstanding narrowband photonic channelization. When combined with the full‐chip photonic RF repeater, broadband, highly integrated, and cost‐effective communications satellite payloads will become realizable more quickly in the near future.

Research on distributed beamforming synchronization technology in inter-satellite link system

Limited by satellite load and carrying capacity, it is difficult for inter-satellite link systems to improve information transmission capabilities by increasing power and antenna size like traditional terrestrial communication systems. Satellite communication payload power has always been an important limitation of long-distance communication performance. In order to improve the satellite’s long-distance communication capability and comprehensively consider the characteristics of Doppler frequency changes in the satellite environment, we propose a cooperative communication algorithm based on weak bit feedback. This algorithm can realize the time and space focusing of the beams emitted by multiple distributed satellite nodes at the destination node, and improve the performance of satellite long-distance communication. This paper simulates the above algorithm based on STK/Matlab software. The simulation results show that the weak bit feedback algorithm has stronger adaptability, faster convergence speed and higher synthesis efficiency under different channel changes. The algorithm is simple and easy to implement, and is suitable for the inter-satellite link environment with many satellite nodes and high scalability. Finally, we conducted hardware experimental verification, analyzed the signal flow of each module in the hardware, and tested it on the USRP software radio platform. The test results show that it is a feasible solution to realize distributed satellite node cooperative communication based on the weak bit feedback algorithm.

Small Satellites for Low-Cost Space Access: Launch, Deployment, Integration, and In-Space Logistics

Satellite launches have skyrocketed in recent years, as they become more affordable to smaller businesses in a variety of sectors. They no longer need as much space to construct it after using digital technology to considerably lower the size of its typical satellite communications payload. As a result, they relocated to a smaller space. A downsized payload may now fit on smaller satellites, providing them with more versatile and powerful communications capabilities that they may not have had before. Small satellites and CubeSats have transformed the space industry by providing an efficient alternative for cost-effective space launches as well as undertaking numerous technological demos, scientific research, Earth exploration, and other missions. Furthermore, since they are easier to design, construct, and launch than conventional satellites, these satellites are widely employed by commercial firms, government, military, and non-profit groups. In this article, we look at how the space industry has grown significantly over the years, resulting in a greater number of startups entering the market. Case studies on tiny satellite and CubeSat manufacturers as well as mission integrator firms are covered. This study also discusses how entrepreneurs may construct the CubeSat ecosystem by developing new methodologies and improved subsystems for the efficient operation of CubeSats. Finally, the article explores current trends as well as potential difficulties and advancements in tiny satellite and CubeSat technologies. This study makes it very evident that having private space enterprises is the only way for a nation to become a member of the global space economy. As a result, one of the country’s most significant responsibilities is to encourage private firms to participate in space operations.

Small Satellites for Low-Cost Space Access: Launch, Deployment, Integration, and In-Space Logistics

Satellite launches have skyrocketed in recent years, as they become more affordable to smaller businesses in a variety of sectors. They no longer need as much space to construct it after using digital technology to considerably lower the size of its typical satellite communications payload. As a result, they relocated to a smaller space. A downsized payload may now fit on smaller satellites, providing them with more versatile and powerful communications capabilities that they may not have had before. Small satellites and CubeSats have transformed the space industry by providing an efficient alternative for cost-effective space launches as well as undertaking numerous technological demos, scientific research, Earth exploration, and other missions. Furthermore, since they are easier to design, construct, and launch than conventional satellites, these satellites are widely employed by commercial firms, government, military, and non-profit groups. In this article, we look at how the space industry has grown significantly over the years, resulting in a greater number of startups entering the market. Case studies on tiny satellite and CubeSat manufacturers as well as mission integrator firms are covered. This study also discusses how entrepreneurs may construct the CubeSat ecosystem by developing new methodologies and improved subsystems for the efficient operation of CubeSats. Finally, the article explores current trends as well as potential difficulties and advancements in tiny satellite and CubeSat technologies. This study makes it very evident that having private space enterprises is the only way for a nation to become a member of the global space economy. As a result, one of the country’s most significant responsibilities is to encourage private firms to participate in space operations.

Optimizing number of spots and cluster size of a high‐throughput communication satellite payload

SummaryIn this paper, the number of spots and cluster size of a high‐throughput satellite (HTS) is optimized by minimizing the satellite mass in the conceptual design phase. An innovative procedure for deriving the total mass of the payload and relevant power supply subsystem as a function of the number of spots and cluster size is presented. For estimating the size and electrical power consumption, the general block diagram of an HTS payload is planned. A direct radiating phased array as the multiple‐beam antenna is used, and its synthesis technique is described briefly. Accordingly, the number of subarrays and elements in each subarray as functions of the number of spots are derived in the presence of orthogonal beams while neglecting the grating lobes. A block diagram for the new generation HTS payloads with digital signal processors for beam forming and data regeneration is presented. The procedure for determining the number of spots and cluster size is extended to the new generation very HTSs with 100 s Gbps link capacity. Conceptual design examples of HTSs with microwave beam forming network and transparent transponder in C‐band, Ka‐band, and for very HTSs with digital beam forming network and regenerative transponder in Ka‐band are provided.

Waveguide Hybrid Septum Coupler

The design of a patented broadwall waveguide hybrid coupler, derived from the working principle of a septum polarizer, is presented. This E-plane coupler requires a single and large aperture in the common broadwall of the two parallel waveguide transmission lines to function, facilitating its manufacturing and assembly. The working principle of this hybrid coupler is detailed, supported by equations making a link with the well-known 3-dB tandem coupler and enabling the definition of a good starting point for optimization purposes. The concept is further validated through the design, manufacture, and test of a prototype working over the frequency range 17.3-20.2 GHz. Good results are obtained over a fractional bandwidth of 19.4% (17.2-20.9 GHz) with axial ratio and return loss (RL) better than 0.5 and 24 dB, respectively. This operating range may be extended up to about 27% (16.8-22.0 GHz) for less demanding applications (axial ratio below 3 dB and RL better than 20 dB). This is a promising solution for the design of advanced feed systems and beamforming networks part of communication satellite payloads.

Photonics‐Based Microwave Frequency Mixing: Methodology and Applications

AbstractPhotonics‐based microwave frequency mixing provides distinct features in terms of wide frequency coverage, broad instantaneous bandwidth, small frequency‐dependent loss, and immunity to electromagnetic interference as compared with its electronic counterpart, which can be a key technical enabler for future broadband and multifunctional RF systems. Herein, all‐optical and optoelectronic microwave frequency mixing techniques are reviewed, with an emphasis on the latest advances in photonics‐based microwave frequency mixers with improved performance in terms of conversion efficiency, dynamic range, mixing‐spur suppression, mixing functionality, and polarization independence. Innovative applications enabled by photonics‐based microwave frequency mixers, such as radio‐over‐fiber communication systems, radar systems, satellite payloads and electronic warfare systems, are also reviewed. In addition, efforts in implementing integrated photonics‐based microwave mixers that lead to a dramatic reduction in size, weight, and power consumption are also reviewed.

Doubly Curved Reflector Design for Hybrid Array Fed Reflector Antennas

This communication discusses a generalized analytical formulation for the design of doubly curved reflectors fed by line sources of any shape, including straight, circular, and even elliptical profiles. The proposed hybrid array fed reflector antenna configuration produces pencil beams from line sources which may be either passive multiple beam line sources or reconfigurable linear phased arrays. The proposed formulation, based on parabolic strips derived from geometrical optics considerations, reduces significantly phase aberrations which were responsible for beam squint and sidelobes imbalance with the previous simpler formulation. Numerical results are presented at Ka-band. This doubly curved reflector design is considered of interest in combination with linear phased arrays to introduce some level of coverage reconfigurability (one-axis beam steering) for on-board broadband satellite communication payloads with a much simpler focal array design when compared to existing planar phased array fed reflector antennas.

Reliability and Cost Focused Optimization Approach for a Communication Satellite Payload Redundancy Allocation Problem

Reliability and Cost Focused Optimization Approach for a Communication Satellite Payload Redundancy Allocation Problem

Implementation of AHP-based reliability allocation for control and monitoring subsystem

Reliability Allocation (RA) is a method for apportionment of reliability values amongst various subsystems and components to achieve a given system reliability target at design stage. RA methods are based on experts' reliability weighting for each subsystem, which is inaccurate for a practical reliability allocation. In this paper, we have proposed a method in which the Analytic Hierarchy Process (AHP) is used as a tool for reliability allocation. Using this technique, we are able to consider all criteria which have effect on reliability. Moreover, by reducing complex decisions to a series of pairwise comparisons, and then synthesising the results, the AHP helps to capture both subjective and objective aspects of a decision and reduce the bias in the decision-making process. The proposed algorithm has been implemented on the control and monitoring subsystem of typical communication satellite payload and the results of the evaluation indicate the efficiency of this method.

Mantle cloaking for co-site radio-frequency antennas

We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

Advanced Antenna Technologies for Satellite Communications Payloads

A review of various antenna technologies suitable for satellite communications and applicable to fixed satellite, broadcast satellite, mobile communications, and personal communications services is presented. Antenna technologies suitable for generating contoured beam and multiple-beam antennas are reviewed. Design considerations for reflector antennas and feed assemblies and antenna performance in terms of coverage gain, sidelobe isolation, and cross-polar isolation are discussed. Current and future technological trends are presented in the above areas.

Digital linear pre‐compensation technique to enhance predistortion performance in multicarrier DVB‐S2 satellite communication systems

Nonlinearity in communication satellite payloads often severely degrades the downlink signal quality in such systems. A digital pre-compensation technique to enhance digital predistortion performance in multicarrier satellite communication systems is presented. The proposed technique has been validated by simulations with an appropriate platform where excellent performance improvements have been measured. In addition, the implementation feasibility of this technique has been briefly demonstrated by means of a real-time FPGA implementation.

The Current Status and Development Trend for Communications Satellite Payloads

Communications satellite payload directly determines the performance of the satellite. In this paper, we focus on these advanced satellite communications systems of representative: WGS, MUOS and AEHF, including function and structure of the payload. Then the development trend of communications satellite payload is analyzed. Some suggestions for the development of China's communications satellite payload are proposed at last.

Optimization of a space based radiator

Nowadays there is an increased demand in satellite weight reduction for the reduction of costs. Thermal control system designers have to face the challenge of reducing both the weight of the system and required heater power while maintaining the components temperature within their design ranges. The main purpose of this paper is to present an optimization of a heat pipe radiator applied to a practical engineering design application. For this study, a communications satellite payload panel was considered. Four radiator areas were defined instead of a centralized one in order to improve the heat rejection into space; the radiator’s dimensions were determined considering worst hot scenario, solar fluxes, heat dissipation and the component’s design temperature upper limit. Dimensions, thermal properties of the structural panel, optical properties and degradation/contamination on thermal control coatings were also considered. A thermal model was constructed for thermal analysis and two heat pipe network designs were evaluated and compared. The model that allowed better radiator efficiency was selected for parametric thermal analysis and optimization. This pursues finding the minimum size of the heat pipe network while keeping complying with thermal control requirements without increasing power consumption.

Electromagnetic Compliance in High Power Communication Satellite Payloads

Electromagnetic compliance in communication payloads is an important aspect and integration of the payload components in the spacecraft bus needs to be done in a well planned manner. In a communication payload satellite, poor EMI environment leads to the overall degraded RF performance. Spacecraft carries a very large number of components and accessories and because of high packing density any modification in the final stage is cumbersome and highly time consuming and irritating. EMI control becomes a tedious or even impossible task at the integrated level as it is difficult to pin point the sources and the sinks, which could be large in number. The problems are often observed in transponders at a late stage in integration when it is difficult to analyze and solve. Salvaging actions do not yield the required improvements and are not fruitful. Some important consequences of radiated interference are (a) presence of spurious signals in the output of a subsystem and (b) degradation of the frequency response of a chain of subsystems after integration. An attempt was made to analyze and quantify the effect of EMI feedback on the frequency response, so that the EMI behavior of subsystems could be co-related with overall gain ripple. An ‘Electromagnetic Compliance Plan’ for Communication Satellite payloads was evolved and implemented successfully with quite satisfactory results.

Transceiver Front-End Technology for Software Radio Implementation ofWideband Satellite Communication Systems

The evolution of satellite communication systems for the design of both the satellite's communication payload and the ground-station are towards the implementation of such systems using the Software Radio (SR) technology. This paper focuses on a key element of the SR, that is, the wideband front-end which still poses the greatest technological challenge for design and proliferation of SR. In particular, we look at the front-end architecture of wideband receivers, outline the key aspects of the design of such front-end systems, specify the performance metrics associated with their design, present an architecture of a promising wideband analog to digital converter, and finally present the results of our design, implementation, and test campaign of a prototype PC-based SR system.

2 A Requirements Driven Approach to Synthesis of Military Satellite Communications Payloads

AbstractThis paper presents a structured approach to synthesizing communications payloads based on expressed requirements of a military client. The approach stresses the functions performed by a communications payload rather than technologies that facilitate their implementation. Benefits of a structured approach include increased focus on client requirements, timely development of realistic payload concepts, enhanced acceptability of those concepts, and a more robust design relative to technology driven designs. A process model is developed. Payload synthesis models are presented.

Historical perspectives on commercial and nonmilitary government space applications of microwave systems in the Baltimore/Washington area

The Baltimore/Washington area has made significant contributions to commercial and nonmilitary government space applications of microwaves. These cover a wide swath extending from R&D laboratory items, basically experimental/proof-of-concept, to space-qualified microwave hardware, subsystems, and systems that were launched and operated in space, to operational Earth terminal subsystems. Microwave efforts also included elements in the design of communications satellite systems, satellite payloads and hardware, and satellites for remote sensing, their payload and some hardware, and radiowave propagation on the slant (Earth-satellite) path. Unique contributions include the Applied Technology Satellite-6 (ATS-6), the discovery and characterization of gigahertz ionospheric scintillation, possibly the first electronically steerable phased array and the invention and implementation of the waveguide multimode filter, the first space-qualifiable monolithic-microwave integrated-circuit chips and subsystems, state-of-the-art altimeters, possibly the first Cesium clock for space and the first high Tc microwave filter.