Satellite edge computing for real-time and very-high resolution Earth observation

In real-time and high-resolution Earth observation imagery, Low Earth Orbit (LEO) satellites capture images that are subsequently transmitted to ground to create an updated map of an area of interest. Such maps provide valuable information for meteorology or environmental monitoring, but can also be employed in near-real time operation for disaster detection, identification, and management. However, the amount of data generated by these applications can easily exceed the communication capabilities of LEO satellites, leading to congestion and packet dropping. To avoid these problems, the Inter-Satellite Links (ISLs) can be used to distribute the data among the satellites for processing. In this paper, we address an energy minimization problem based on a general satellite mobile edge computing (SMEC) framework for real-time and very-high resolution Earth observation. Our results illustrate that the optimal allocation of data and selection of the compression parameters increase the amount of images that the system can support by a factor of 12 when compared to directly downloading the data. Further, energy savings greater than 11% were observed in a real-life scenario of imaging a volcanic island, while a sensitivity analysis of the image acquisition process demonstrates that potential energy savings can be as high as 92%.Comment: submitted for publication to IEEE Transactions in Communication

Quantum Communication, Sensing and Measurement in Space

The main theme of the conclusions drawn for classical communication systems operating at optical or higher frequencies is that there is a well‐understood performance gain in photon efficiency (bits/photon) and spectral efficiency (bits/s/Hz) by pursuing coherent‐state transmitters (classical ideal laser light) coupled with novel quantum receiver systems operating near the Holevo limit (e.g., joint detection receivers). However, recent research indicates that these receivers will require nonlinear and nonclassical optical processes and components at the receiver. Consequently, the implementation complexity of Holevo‐capacityapproaching receivers is not yet fully ascertained. Nonetheless, because the potential gain is significant (e.g., the projected photon efficiency and data rate of MIT Lincoln Laboratory's Lunar Lasercom Demonstration (LLCD) could be achieved with a factor‐of‐20 reduction in the modulation bandwidth requirement), focused research activities on ground‐receiver architectures that approach the Holevo limit in space‐communication links would be beneficial. The potential gains resulting from quantum‐enhanced sensing systems in space applications have not been laid out as concretely as some of the other areas addressed in our study. In particular, while the study period has produced several interesting high‐risk and high‐payoff avenues of research, more detailed seedlinglevel investigations are required to fully delineate the potential return relative to the state‐of‐the‐art. Two prominent examples are (1) improvements to pointing, acquisition and tracking systems (e.g., for optical communication systems) by way of quantum measurements, and (2) possible weak‐valued measurement techniques to attain high‐accuracy sensing systems for in situ or remote‐sensing instruments. While these concepts are technically sound and have very promising bench‐top demonstrations in a lab environment, they are not mature enough to realistically evaluate their performance in a space‐based application. Therefore, it is recommended that future work follow small focused efforts towards incorporating practical constraints imposed by a space environment. The space platform has been well recognized as a nearly ideal environment for some of the most precise tests of fundamental physics, and the ensuing potential of scientific advances enabled by quantum technologies is evident in our report. For example, an exciting concept that has emerged for gravity‐wave detection is that the intermediate frequency band spanning 0.01 to 10 Hz—which is inaccessible from the ground—could be accessed at unprecedented sensitivity with a space‐based interferometer that uses shorter arms relative to state‐of‐the‐art to keep the diffraction losses low, and employs frequency‐dependent squeezed light to surpass the standard quantum limit sensitivity. This offers the potential to open up a new window into the universe, revealing the behavior of compact astrophysical objects and pulsars. As another set of examples, research accomplishments in the atomic and optics fields in recent years have ushered in a number of novel clocks and sensors that can achieve unprecedented measurement precisions. These emerging technologies promise new possibilities in fundamental physics, examples of which are tests of relativistic gravity theory, universality of free fall, frame‐dragging precession, the gravitational inverse‐square law at micron scale, and new ways of gravitational wave detection with atomic inertial sensors. While the relevant technologies and their discovery potentials have been well demonstrated on the ground, there exists a large gap to space‐based systems. To bridge this gap and to advance fundamental‐physics exploration in space, focused investments that further mature promising technologies, such as space‐based atomic clocks and quantum sensors based on atom‐wave interferometers, are recommended. Bringing a group of experts from diverse technical backgrounds together in a productive interactive environment spurred some unanticipated innovative concepts. One promising concept is the possibility of utilizing a space‐based interferometer as a frequency reference for terrestrial precision measurements. Space‐based gravitational wave detectors depend on extraordinarily low noise in the separation between spacecraft, resulting in an ultra‐stable frequency reference that is several orders of magnitude better than the state of the art of frequency references using terrestrial technology. The next steps in developing this promising new concept are simulations and measurement of atmospheric effects that may limit performance due to non‐reciprocal phase fluctuations. In summary, this report covers a broad spectrum of possible new opportunities in space science, as well as enhancements in the performance of communication and sensing technologies, based on observing, manipulating and exploiting the quantum‐mechanical nature of our universe. In our study we identified a range of exciting new opportunities to capture the revolutionary capabilities resulting from quantum enhancements. We believe that pursuing these opportunities has the potential to positively impact the NASA mission in both the near term and in the long term. In this report we lay out the research and development paths that we believe are necessary to realize these opportunities and capitalize on the gains quantum technologies can offer

Multichannel interference mitigation methods in radio astronomy

Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language, and give an introduction to some elementary algorithms from that field. We consider two topics in detail: interference detection by rank estimation of short-term covariance matrices, and spatial filtering by subspace estimation and projection. We discuss experimental data collected at the Westerbork radio telescope, and illustrate the effectiveness of the space-time detection and blanking process on the recovery of a 3C48 absorption line in the presence of GSM mobile telephony interference.Comment: 39 pages, 18 figures.Enhanced figures can be downloaded from http://cas.et.tudelft.nl/~leshem/postscripts/leshem/figs34567.ps.gz To appear in Astrophysical Journal Supplements serie

Nanosatellite optical downlink experiment: design, simulation, and prototyping

The nanosatellite optical downlink experiment (NODE) implements a free-space optical communications (lasercom) capability on a CubeSat platform that can support low earth orbit (LEO) to ground downlink rates>10  Mbps. A primary goal of NODE is to leverage commercially available technologies to provide a scalable and cost-effective alternative to radio-frequency-based communications. The NODE transmitter uses a 200-mW 1550-nm master-oscillator power-amplifier design using power-efficient M-ary pulse position modulation. To facilitate pointing the 0.12-deg downlink beam, NODE augments spacecraft body pointing with a microelectromechanical fast steering mirror (FSM) and uses an 850-nm uplink beacon to an onboard CCD camera. The 30-cm aperture ground telescope uses an infrared camera and FSM for tracking to an avalanche photodiode detector-based receiver. Here, we describe our approach to transition prototype transmitter and receiver designs to a full end-to-end CubeSat-scale system. This includes link budget refinement, drive electronics miniaturization, packaging reduction, improvements to pointing and attitude estimation, implementation of modulation, coding, and interleaving, and ground station receiver design. We capture trades and technology development needs and outline plans for integrated system ground testing.United States. National Aeronautics and Space Administration. Research Fellowship ProgramLincoln Laboratory (Lincoln Scholars)Lincoln Laboratory (Military Fellowship Program)Fundación Obra Social de La Caixa (Fellowship)Samsung FellowshipUnited States. Air Force (Assistant Secretary of Defense for Research & Engineering. Contract FAs872105C0002

Antenna Designs for 5G/IoT and Space Applications

This book is intended to shed some light on recent advances in antenna design for these new emerging applications and identify further research areas in this exciting field of communications technologies. Considering the specificity of the operational environment, e.g., huge distance, moving support (satellite), huge temperature drift, small dimension with respect to the distance, etc, antennas, are the fundamental device allowing to maintain a constant interoperability between ground station and satellite, or different satellites. High gain, stable (in temperature, and time) performances, long lifecycle are some of the requirements that necessitates special attention with respect to standard designs. The chapters of this book discuss various aspects of the above-mentioned list presenting the view of the authors. Some of the contributors are working strictly in the field (space), so they have a very targeted view on the subjects, while others with a more academic background, proposes futuristic solutions. We hope that interested reader, will find a fertile source of information, that combined with their interest/background will allow efficiently exploiting the combination of these two perspectives

Kapeankaistan LTE koneiden välisessä satelliittitietoliikenteessä

Recent trends to wireless Machine-to-Machine (M2M) communication and Internet of Things (IoT) has created a new demand for more efficient low-throughput wireless data connections. Beside the traditional wireless standards, focused on high bandwidth data transfer, has emerged a new generation of Low Power Wide Area Networks (LPWAN) which targets for less power demanding low-throughput devices requiring inexpensive data connections. Recently released NB-IoT (Narrowband IoT) specification extends the existing 4G/LTE standard allowing more easily accessible LPWAN cellular connectivity for IoT devices. Narrower bandwidth and lower data rates combined to a simplified air interface make it less resource demanding still benefiting from the widely spread LTE technologies and infrastructure. %% Applications & Why space Applications, such as wide scale sensor or asset tracking networks, can benefit from a global scale network coverage and easily available low-cost user equipment which could be made possible by new narrowband IoT satellite networks. In this thesis, the NB-IoT specification and its applicability for satellite communication is discussed. Primarily, LTE and NB-IoT standards are designed only for terrestrial and their utilization in Earth-to-space communication raises new challenges, such as timing and frequency synchronization requirements when utilizing Orthogonal Frequency Signal Multiplexing (OFDM) techniques. Many of these challenges can be overcome by specification adaptations and other existing techniques making minimal changes to the standard and allowing extension of the terrestrial cellular networks to global satellite access.Viimeaikaiset kehitystrendit koneiden välisessä kommunikaatiossa (Machine to Machine Communication, M2M) ja esineiden Internet (Internet of Things, IoT) -sovelluksissa ovat luoneet perinteisteisten nopean tiedonsiirron langattomien standardien ohelle uuden sukupolven LPWAN (Low Power Wide Area Networks) -tekniikoita, jotka ovat tarkoitettu pienitehoisille tiedonsiirtoa tarvitseville sovelluksille. Viimeaikoina yleistynyt NB-IoT standardi laajentaa 4G/LTE standardia mahdollistaen entistä matalamman virrankulutuksen matkapuhelinyhteydet IoT laitteissa. Kapeampi lähetyskaista ja hitaampi tiedonsiirtonopeus yhdistettynä yksinkertaisempaan ilmarajapintaan mahdollistaa pienemmän resurssivaatimukset saman aikaan hyötyen laajalti levinneistä LTE teknologioista ja olemassa olevasta infrastruktuurista. Useissa sovelluskohteissa, kuten suurissa sensoriverkoissa, voitaisiin hyötyä merkittävästi globaalista kattavuudesta yhdistettynä edullisiin helposti saataviin päätelaitteisiin. Tässä työssä käsitellään NB-IoT standardia ja sen soveltuvuutta satellittitietoliikenteeseen. LTE ja NB-IoT ovat kehitty maanpääliseen tietoliikenteeseen ja niiden hyödyntäminen avaruuden ja maan välisessä kommunikaatiossa aiheuttaa uusia haasteita esimerkiksi aika- ja taajuussynkronisaatiossa ja OFDM (Orthogonal Frequency Signal Multiplexing) -tekniikan hyödyntämisessä. Nämä haasteet voidaan ratkaista soveltamalla spesifikaatiota sekä muilla jo olemassa olevilla tekniikoilla tehden mahdollisimman vähän muutoksia alkuperäiseen standardiin, ja täten sallien maanpäälisten IoT verkkojen laajenemisen avaruuteen

Developing a Methane Detector for Aerospace Applications

Greenhouse gasses in the atmosphere are raising the global temperature and causing adverse side effects. Of these greenhouse gasses, methane is one of the most impactful, second only to carbon dioxide. One of the methods for determining the concentration of methane in the atmosphere is taking images of the earth from space. The purpose of this project is to further a new imaging technology for detecting methane leaks called FINIS (Filter Incidence Narrow-band Infrared Spectrometer), thus improving our capability to detect and locate methane leaks and reduce greenhouse gas emissions. FINIS has been developed in various stages since 2018 and has been accepted to fly on a CubeSat called ACMES (Active Cooling for Multispectral Earth Sensors) in 2024. My thesis will explore a new and optimized design for FINIS to be implemented on a CubeSat and determine whether it can survive the space environment. As part of the design and testing process, we will determine whether the precision of the FINIS instrument is comparable to other satellites observing methane. FINIS is estimated to be more compact, capable, and affordable than previous space-based sensors and has the potential for providing a next-generation methane sensor