Browse Topic: Satellite communications
ABSTRACT Continued proliferation of terrorist activities throughout the globe, as well as other low to medium intensity conflicts, present unique challenges to the US Army, Marines, and Special Operating Forces, especially in times of reduced manpower and operating budgets. Soldiers are called upon to do increasingly complex, dangerous, and lengthy missions with reduced troop strength and in more remote and austere conditions often far from traditional means of ready resupply. The need for organic persistent surveillance of potentially hostile areas is also of significant value to improve situational awareness and preserve the tactical advantage. The high risk nature of these missions can be significantly mitigated and operational tempo (OPTEMPO) improved by using unmanned solutions. Previously proposed solutions attempting to make use of Unmanned Ground Vehicles (UGVs) or Unmanned Air Vehicles (UAVs) alone experienced multiple problems. One solution that addresses these issues is to
ABSTRACT This paper presents a new concept in GNSS navigation: Sequential Lock GPS (GPS-SL). The new concept and prototype provide a variety of advantages for robustness, solution maintenance, and jamming resistance. Under normal circumstances, GNSS receivers need to receive signals from four satellites simultaneously to get a fix on position and the receiver time bias. If three or less satellites are visible given the occlusions provided by the environment, or because someone/something is intentionally or unintentionally jamming the space, no benefit is provided to the navigation solution. In other words, four or more simultaneous satellites give you a fix, three or less simultaneous satellites usually do not contribute (with some caveats) at all
ABSTRACT Tactical Radio Systems such as the Mid-Tier Networking Vehicular Radio (MNVR) and the Handheld, Manpack, and Small Form Fit (HMS) Radio provide common functions that can be componentized with standardized interfaces. In the Army’s acquisition and testing processes, next generation radios are being fielded with related systems and components as capabilities. Model-Based Systems Engineering (MBSE) is an ideal methodology to develop a Reference Architecture using a common development process. MBSE uses a formal model of a system of systems to represent all systems engineering information. Key benefits of MBSE include traceability, communication, configuration management and common languages and notations. This paper evaluates implementation experiences in applying MBSE to develop a Reference Architecture (RA) that provides VICTORY interfaces for radio, computing systems, and Satellite Communications (SATCOM) terminals. The information representation of the Hardware/Software (HW
Satellite propulsion systems have traditionally been designed for high reliability over large-scale production. Engineered for specific, high-stakes missions, these systems are produced in limited quantities — often only a few dozen units or less. Today, the advent of Low Earth Orbit (LEO) satellite constellations is changing this dynamic, ushering in new commercial and military opportunities that involve deploying hundreds or thousands of satellites designed for research, telecommunications, and Earth observation applications
University of Colorado Boulder Boulder, CO 303-735-4900
Manufacturing and servicing facilities in space are (finally) moving from the pages of science fiction to reality. For decades, we've seen movies with scenes of spacecraft being created and serviced in beautifully rendered factories with Earth in the background. And many more ideas have come from authors imagining bold futures where humanity does everything from creating giant nets of satellites to massive, spinning space stations. Some might lament that, back in reality, we’ve come so far with our achievements in space yet fallen short of the brightest visions. How can we have landed on the Moon 50 years ago and still be scrapping billion-dollar satellites when they run out of fuel? However, there’s good reason to believe that the space industry is almost done laying the foundations that will let us move from science fiction to engineering reality
Launch vehicle structures in course of its flight will be subjected to dynamic forces over a range of frequencies up to 2000 Hz. These loads can be steady, transient or random in nature. The dynamic excitations like aerodynamic gust, motor oscillations and transients, sudden application of control force are capable of exciting the low frequency structural modes and cause significant responses at the interface of launch vehicle and satellite. The satellite interface responses to these low frequency excitations are estimated through Coupled Load Analysis (CLA). This analysis plays a crucial role in mission as the satellite design loads and Sine vibration test levels are defined based on this. The perquisite of CLA is to predict the responses with considerable accuracy so that the design loads are not exceeded in the flight. CLA validation is possible by simulating the flight experienced responses through the analysis. In the present study, the satellite interface responses are validated
L3Harris Technologies Melbourne, FL 585-465-3592
This study presents the constructed electromechanical model and the analysis of the obtained nonlinear systems. An algorithm for compensating the nonlinear drift of a gyroscope in a microelectromechanical system is proposed. Tests were carried out on a precision rotating base, with the angular velocity changing as per the program. Bench testing the gyroscope confirmed the results, which were also supported by the parameter calibration. The analytical method was further validated through experimental results, and a correction algorithm for the mathematical model was developed based on the test results. After calibration and adjusting the gyroscope’s systematic flaws, the disparity in calculating the precession angle was within 1/100th of an angular second over an interval of approximately 1000 s. Currently, research is underway on the new nonlinear dynamic characteristics of electrostatically controlled microstructures. The results of the integrated navigation system of small satellites
Intelsat McLean, VA 240-308-1881
New algorithm strategies and diverse communication techniques are constantly emerging in the telecommunications realm that consumers, commercial, government, and military demand in order to push the boundaries of data throughput to receive information as quickly as possible. Currently, the Ku/Ka satellite band (20–30 GHz) becomes congested during peak service. There has been a strong demand for a wider bandwidth and higher data rate in both cellular and satellite communication service. As the carrier frequency increases, a wider bandwidth can be made available, and a higher data rate can be obtained with beamforming or precoding. Particularly, the V band (50–75 GHz) and W band (75–110 GHz) offer unprecedented broadband capabilities and extremely large contiguous allocations of bandwidth. This is the reason NASA and AFRL have been investigating these bands for civilian and military use
The impact on wireless communication system performance was investigated for five channel conditions, which included (1) additive white Gaussian noise, (2) flat Raleigh fading, (3) frequency selective Raleigh fading, (4) flat Rician fading, and (5) frequency selective Rician fading. Wichita State University, Wichita, Kansas New algorithm strategies and diverse communication techniques are constantly emerging in the telecommunications realm that consumers, commercial, government, and military demand in order to push the boundaries of data throughput to receive information as quickly as possible. Currently, the Ku/Ka satellite band (20-30 GHz) becomes congested during peak service. There has been a strong demand for a wider bandwidth and higher data rate in both cellular and satellite communication service. As the carrier frequency increases, a wider bandwidth can be made available, and a higher data rate can be obtained with beamforming or precoding. Particularly, the V band (50-75 GHz
New satellites equipped with Corning’s advanced hyperspectral-imaging technology can detect pipeline leaks and other environmental issues, providing precise monitoring and exploration capabilities for businesses and governments
Rensselaer Polytechnic Institute’s Moussa N’Gom has devised a method to make communications between satellites and the ground more effective — regardless of the weather. N’Gom and his team used ultrafast, femtosecond lasers to cut through the clouds and rain that commonly cause losses in free-space optical communication (FSO
Researchers have developed an algorithm that can “eavesdrop” on any signal from a satellite and use it to locate any point on Earth, much like GPS. The study represents the first time an algorithm was able to exploit signals broadcast by multi-constellation low-Earth orbit (LEO) satellites, namely Starlink, OneWeb, Orbcomm, and Iridium
Most space satellites are powered by photovoltaic cells that convert sunlight to electricity. Exposure to certain orbit radiation can damage the devices, degrading their performance and limiting their lifetime. University of Cambridge scientists have proposed a radiation-tolerant photovoltaic cell design that features an ultrathin layer of light-absorbing material
NASA launches satellites, rovers, and orbiters to investigate humanity’s place in the Milky Way. When these missions reach their destinations, their scientific instruments capture images, videos, and valuable insights about the cosmos. Communications infrastructure in space and on the ground enables the data collected by these missions to reach Earth. Without ground stations to receive it, however, the extraordinary data captured by these missions would be stuck in space, unable to reach scientists and researchers on Earth
Litter is not only a problem on Earth. According to NASA, there are currently millions of pieces of space junk in the range of altitudes from 200 to 2000 kilometers above the Earth’s surface, which is known as low-Earth orbit (LEO). Most of the junk is comprised of objects created by humans, like pieces of old spacecraft or defunct satellites. This space debris can reach speeds of up to 18,000 miles per hour, posing a major danger to the 2612 satellites that currently operate at LEO. Without effective tools for tracking space debris, parts of LEO may even become too hazardous for satellites
Historically, patch antennas have been used for SmallSat communications. While new antenna technologies are in development, some are not optimized for size, mass, and performance — especially beyond low-Earth orbit (LEO). Engineers at NASA’s Marshall Space Flight Center identified the need for a small form factor antenna to provide high data rate communications for such missions
Synthetic Aperture Radar (SAR) images are a powerful tool for studying the Earth’s surface. They are radar signals generated by an imaging system mounted on a platform such as an aircraft or satellite. As the platform moves, the system emits sequentially high-power electromagnetic waves through its antenna. The waves are then reflected by the Earth’s surface, re-captured by the antenna, and finally processed to create detailed images of the terrain below
Rensselaer Polytechnic Institute’s Moussa N’Gom has devised a method to make communications between satellites and the ground more effective — regardless of the weather. N’Gom and his team used ultrafast, femtosecond lasers to cut through the clouds and rain that commonly cause losses in free-space optical communication (FSO
An extensive evaluation of the Deep Image Prior (DIP) technique for image inpainting on Synthetic Aperture Radar (SAR) images. Air Force Research Laboratory, Wright Patterson Air Force Base, OH Synthetic Aperture Radar (SAR) images are a powerful tool for studying the Earth's surface. They are radar signals generated by an imaging system mounted on a platform such as an aircraft or satellite. As the platform moves, the system emits sequentially high-power electromagnetic waves through its antenna. The waves are then reflected by the Earth's surface, re-captured by the antenna, and finally processed to create detailed images of the terrain below. SAR images are employed in a wide variety of applications. Indeed, as the waves hit different objects, their phase and amplitude are modified according to the objects' characteristics (e.g., permittivity, roughness, geometry, etc.). The collected signal provides highly detailed information about the shape and elevation of the Earth's surface
Volcanic eruptions, floods, and tornadoes can all dramatically change the surface of Earth to the point where alterations can be seen from space. Some modifications driven by human intervention, such as mining and deforestation, are also visible in satellite imagery. For the past 50 years, NASA’s Landsat satellites have recorded our planet’s changing surface. Now maps from a company called terraPulse Inc. help academic institutions, nongovernmental organizations, and businesses see, understand, and manage those changes
The Current Icing Product (CIP; Bernstein et al. 2005) and Forecast Icing Product (FIP; Wolff et al. 2009) were originally developed by the United States’ National Center for Atmospheric Research (NCAR) under sponsorship of the Federal Aviation Administration (FAA) in the mid 2000’s and provide operational icing guidance to users through the NOAA Aviation Weather Center (AWC). The current operational version of FIP uses the Rapid Refresh (RAP; Benjamin et al. 2016) numerical weather prediction (NWP) model to provide hourly forecasts of Icing Probability, Icing Severity, and Supercooled Large Drop (SLD) Potential. Forecasts are provided out to 18 hours over the Contiguous United States (CONUS) at 15 flight levels between 1,000 ft and FL290, inclusive, and at a 13-km horizontal resolution. CIP provides similar hourly output on the same grid, but utilizes geostationary satellite data, ground-based radar data, Meteorological Terminal Air Reports (METARS), lightning data, and voice pilot
RF cable assemblies might appear to be a minor component in system design, but they can make all the difference between success and failure, especially in mission-critical industries such as defense and space. The RF interconnect is the vital bridge between many critical systems, including payload, communications, signal transport, and processing. This article will primarily focus on hypersonic missile systems and satellites to illustrate these concepts, as they jointly highlight the importance of RF cable assembly design in extreme environments
The prevailing mission-based paradigm for ocean color remote sensing typically involves high-cost satellite platforms launched and operated by government agencies such as NASA, NOAA, ESA, and JAXA. These platforms host state-of-the-art ocean-viewing radiometers with design and sensitivity specifications appropriate for delineating a comparatively weak water-leaving radiance from the total radiant signal detected at the top of the atmosphere. The current suite of such operational ocean color sensors includes NASA’s Moderate Resolution Imaging Spectroradi-ometer (MODIS; Aqua satellite), NOAA’s VIIRS (SNPP and NOAA-20 satellites), the Ocean and Land Color Instrument (OLCI; Sentinel-3 A/B satellites), and the Second-Generation Global Imager (SGLI) onboard the GCOM-C satellite. All of these sensors provide multi-spectral band sets (visible, near-infrared (NIR), and shortwave infrared (SWIR)) with daily coverage at approximately kilometer-scale spatial resolution. However, even kilometer
Forty-five years ago, the Voyager 2 spacecraft launched on a mission to visit the outer planets. One vital component of the craft that still works is the key to getting data as it leaves the solar system. But this piece of the now-interstellar spacecraft, the traveling-wave tube (TWT), has also become a necessary component for utilizing microwaves in several applications back on Earth. For example, satellite radio spacecraft use the amplification power of TWTs, and thanks to NASA’s help listeners have coverage over all of North America and receive better-sounding audio
Scientists at NASA’s Langley Research Center have developed a novel concept for a lunar navigation system based on the reverse-ephemeris technique. Typically, range-related signal measurements from the Earth’s surface are used to locate and track orbital objects (satellites) and establish the ephemeris describing their orbits. For this reverse-ephemeris lunar navigation concept, the process is reversed to give lunar surface position fixes using the known ephemeris of a satellite in lunar orbit
A team of MIT scientists has created the first completely digitally manufactured plasma sensors — also known as retarding potential analyzers (RPAs) — for orbiting spacecraft. The sensors are used by satellites to determine the chemical composition and ion energy distribution of the atmosphere
Over the last few years, there has been a dramatic increase in the number of satellites in orbit. A significant portion of this increase is thanks to the smaller size of newer satellites. Although the largest orbiting structure, the International Space Station, is larger than a football field, most of the satellites in orbit today are much closer in size to a football. This is in part due to the popularity of the CubeSat form factor, with a so-called 1U satellite fitting within a 10 cm x 10 cm x 10 cm envelope. The small size makes it possible to launch multiple satellites from a single rocket. Although originally envisioned for mostly academic purposes, there is now a robust commercial ecosystem providing design solutions ranging from 1U to 24U — and the use of CubeSats is growing at a remarkable rate
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