9,199 research outputs found
Terrestrial applications: An intelligent Earth-sensing information system
For Abstract see A82-2214
Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View
Small satellite systems enable whole new class of missions for navigation,
communications, remote sensing and scientific research for both civilian and
military purposes. As individual spacecraft are limited by the size, mass and
power constraints, mass-produced small satellites in large constellations or
clusters could be useful in many science missions such as gravity mapping,
tracking of forest fires, finding water resources, etc. Constellation of
satellites provide improved spatial and temporal resolution of the target.
Small satellite constellations contribute innovative applications by replacing
a single asset with several very capable spacecraft which opens the door to new
applications. With increasing levels of autonomy, there will be a need for
remote communication networks to enable communication between spacecraft. These
space based networks will need to configure and maintain dynamic routes, manage
intermediate nodes, and reconfigure themselves to achieve mission objectives.
Hence, inter-satellite communication is a key aspect when satellites fly in
formation. In this paper, we present the various researches being conducted in
the small satellite community for implementing inter-satellite communications
based on the Open System Interconnection (OSI) model. This paper also reviews
the various design parameters applicable to the first three layers of the OSI
model, i.e., physical, data link and network layer. Based on the survey, we
also present a comprehensive list of design parameters useful for achieving
inter-satellite communications for multiple small satellite missions. Specific
topics include proposed solutions for some of the challenges faced by small
satellite systems, enabling operations using a network of small satellites, and
some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications
Surveys and Tutorial
Workshop proceedings: Information Systems for Space Astrophysics in the 21st Century, volume 1
The Astrophysical Information Systems Workshop was one of the three Integrated Technology Planning workshops. Its objectives were to develop an understanding of future mission requirements for information systems, the potential role of technology in meeting these requirements, and the areas in which NASA investment might have the greatest impact. Workshop participants were briefed on the astrophysical mission set with an emphasis on those missions that drive information systems technology, the existing NASA space-science operations infrastructure, and the ongoing and planned NASA information systems technology programs. Program plans and recommendations were prepared in five technical areas: Mission Planning and Operations; Space-Borne Data Processing; Space-to-Earth Communications; Science Data Systems; and Data Analysis, Integration, and Visualization
Linear Precoding performance analysis in a Broadband satellite system with a 2-color dual-polarization reuse scheme
The potential of Joint Multiuser Processing in multi-beam satellite systems is assessed in this paper and proved to be a potential attractive alternative to current systems. The present contribution aims at investigating linear precoding techniques over an accurate multi-beam architecture modeling and system characterization. Power and precoder design problems are approached through well-known linear precoding techniques such as Zero Forcing (ZF) and Regularized-ZF. A dual-polarization 2-color reutilization scheme is considered in combination with precoding techniques. Results show a total throughput improvement of +22% achieved by ZF and +38% considering R-ZF, with respect to a conventional 4-color reuse scheme scenario
On-board Change Detection for Resource-efficient Earth Observation with LEO Satellites
The amount of data generated by Earth observation satellites can be enormous,
which poses a great challenge to the satellite-to-ground connections with
limited rate. This paper considers problem of efficient downlink communication
of multi-spectral satellite images for Earth observation using change
detection. The proposed method for image processing consists of the joint
design of cloud removal and change encoding, which can be seen as an instance
of semantic communication, as it encodes important information, such as changed
multi-spectral pixels (MPs), while aiming to minimize energy consumption. It
comprises a three-stage end-to-end scoring mechanism that determines the
importance of each MP before deciding its transmission. Specifically, the
sensing image is (1) standardized, (2) passed through a high-performance cloud
filtering via the Cloud-Net model, and (3) passed to the proposed scoring
algorithm that uses Change-Net to identify MPs that have a high likelihood of
being changed, compress them and forward the result to the ground station. The
experimental results indicate that the proposed framework is effective in
optimizing energy usage while preserving high-quality data transmission in
satellite-based Earth observation applications
Next Generation High Throughput Satellite System
This paper aims at presenting an overview of the state-of-the-art in High Throughput Satellite (HTS) systems for Fixed Satellite Services (FSS) and High Density-FSS. Promising techniques and innovative strategies that can enhance system performance are reviewed and analyzed aiming to show what to expect for next generation ultra-high capacity satellite systems. Potential air interface evolutions, efficient frequency plans,feeder link dimensioning strategies and interference cancellation techniques are presented to show how Terabit/s satellite myth may turn into reality real soon
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