515 research outputs found
Design and Performance of a Communications System for a Low-Cost High Altitude Balloon Platform for Troposphere and Stratosphere Research
AFOSR Multidisciplinary University Research Initiative (MURI), Integrated Measurement and Modeling Characterization of Stratospheric Turbulence , is a 5-year effort to resolve significant operational issues concerning hypersonic vehicle aerothermodynamics, boundary layer stability, and aero-optical propagation. In situ turbulence measurements along with modeling will quantify spatiotemporal statistics and the dependence of stratospheric turbulence on underlying meteorology to a degree not previously possible. Data from high altitude balloons sampling up to kHz is required to characterize turbulence to the inner-scale, or smaller, over paltitudes from 20 km to 35+ km.
This thesis presents the development of a standard balloon bus, based on reliable COTS components, that includes radios operating in Ham/ISM frequencies with high-gain ground station antennas to achieve high telemetry rates that potentially enable sub-cm scale sampling. It also presents the development of controlled descent systems based on reliable COTS components that allow high resolution unperturbed measurements during the descent of the balloon payloads. Both single and double balloon configurations for a controlled descent are investigated while maintaining a suitable cost for mass production of the system. We are also investigating configurations for multiple ground station to allow the use of Single Payload Multiple Ground Stations strategies to facilitate low error rate high volume data downlinking and closely-timed launches. The performance of using some retransmission techniques to download the data over altitudes from 20 to 35+km when the balloon is out of the altitude range of interest (below 20 km) is analyzed; thus, being able to reduce the percentage of packet losses even during slow descent rates, reaching long slant ranges.
This thesis is designed and implemented using Arduino IDE and MATLAB for software development and testing, circuit design with National Instrument\u27s Multisim and Ultiboard, transceivers configuration with proprietary software, extensive components and system testing, 3D printing, temperature calibrations using a TestEquity temperature chamber, and actual high-altitude balloon launches for final performance analysis
Airships: A New Horizon for Science
The "Airships: A New Horizon for Science" study at the Keck Institute for
Space Studies investigated the potential of a variety of airships currently
operable or under development to serve as observatories and science
instrumentation platforms for a range of space, atmospheric, and Earth science.
The participants represent a diverse cross-section of the aerospace sector,
NASA, and academia. Over the last two decades, there has been wide interest in
developing a high altitude, stratospheric lighter-than-air (LTA) airship that
could maneuver and remain in a desired geographic position (i.e.,
"station-keeping") for weeks, months or even years. Our study found
considerable scientific value in both low altitude (< 40 kft) and high altitude
(> 60 kft) airships across a wide spectrum of space, atmospheric, and Earth
science programs. Over the course of the study period, we identified
stratospheric tethered aerostats as a viable alternative to airships where
station-keeping was valued over maneuverability. By opening up the sky and
Earth's stratospheric horizon in affordable ways with long-term flexibility,
airships allow us to push technology and science forward in a project-rich
environment that complements existing space observatories as well as aircraft
and high-altitude balloon missions.Comment: This low resolution version of the report is 8.6 MB. For the high
resolution version see: http://kiss.caltech.edu/study/airship
A Primer on HIBS -- High Altitude Platform Stations as IMT Base Stations
Mobile communication via high-altitude platforms operating in the
stratosphere is an idea that has been on the table for decades. In the past few
years, however, with recent advances in technology and parallel progress in
standardization and regulatory bodies like 3GPP and ITU, these ideas have
gained considerable momentum. In this article, we present a comprehensive
overview of HIBS - High Altitude Platform Stations as IMT Base Stations. We lay
out possible use cases and summarize the current status of the development,
from a technological point of view as well as from standardization in 3GPP, and
regarding spectrum aspects. We then present preliminary system level simulation
results to shed light on the performance of HIBS. We conclude with pointing out
several directions for future research.Comment: 7 pages, 4 figure
The Sunrise Mission
The first science flight of the balloon-borne \Sunrise telescope took place
in June 2009 from ESRANGE (near Kiruna/Sweden) to Somerset Island in northern
Canada. We describe the scientific aims and mission concept of the project and
give an overview and a description of the various hardware components: the 1-m
main telescope with its postfocus science instruments (the UV filter imager
SuFI and the imaging vector magnetograph IMaX) and support instruments (image
stabilizing and light distribution system ISLiD and correlating wavefront
sensor CWS), the optomechanical support structure and the instrument mounting
concept, the gondola structure and the power, pointing, and telemetry systems,
and the general electronics architecture. We also explain the optimization of
the structural and thermal design of the complete payload. The preparations for
the science flight are described, including AIV and ground calibration of the
instruments. The course of events during the science flight is outlined, up to
the recovery activities. Finally, the in-flight performance of the
instrumentation is briefly summarized.Comment: 35 pages, 17 figure
Near-Space Communications: the Last Piece of 6G Space-Air-Ground-Sea Integrated Network Puzzle
This article presents a comprehensive study on the emerging near-space
communications (NS-COM) within the context of space-air-ground-sea integrated
network (SAGSIN). Specifically, we firstly explore the recent technical
developments of NS-COM, followed by the discussions about motivations behind
integrating NS-COM into SAGSIN. To further demonstrate the necessity of NS-COM,
a comparative analysis between the NS-COM network and other counterparts in
SAGSIN is conducted, covering aspects of deployment, coverage, channel
characteristics and unique problems of NS-COM network. Afterwards, the
technical aspects of NS-COM, including channel modeling, random access, channel
estimation, array-based beam management and joint network optimization, are
examined in detail. Furthermore, we explore the potential applications of
NS-COM, such as structural expansion in SAGSIN communication, civil aviation
communication, remote and urgent communication, weather monitoring and carbon
neutrality. Finally, some promising research avenues are identified, including
stratospheric satellite (StratoSat) -to-ground direct links for mobile
terminals, reconfigurable multiple-input multiple-output (MIMO) and holographic
MIMO, federated learning in NS-COM networks, maritime communication,
electromagnetic spectrum sensing and adversarial game, integrated sensing and
communications, StratoSat-based radar detection and imaging, NS-COM assisted
enhanced global navigation system, NS-COM assisted intelligent unmanned system
and free space optical (FSO) communication. Overall, this paper highlights that
the NS-COM plays an indispensable role in the SAGSIN puzzle, providing
substantial performance and coverage enhancement to the traditional SAGSIN
architecture.Comment: 28 pages, 8 figures, 2 table
Investigating the effect of High Altitude Platform Positioning on Latency and Coverage of 4G Cellular Systems
Wireless communication technologies are rapidly being adopted and developed by countries all over the world as a strategy for sustaining a digital economy. This has proven very useful for economic recovery from the crises brought about by the COVID-19 pandemic of the year 2020. The latency and coverage area of a wireless network are two major areas that are always seeking improvement. The High Altitude Platform communication technology can provide improvement in speed and coverage area for 4G cellular systems. This work investigated the effect of positioning High Altitude Platforms on the latency and coverage of 4G cellular Systems. A quantitative approach was used in the methodology of this paper. A HAP model showing a single platform flying in a circular trajectory over Base Transceiver Stations BTSs and serving as a relay mobile station was presented. A detailed simulation algorithm for the HAP and results for the simulation were given. Results showed that using the HAP as a relay mobile station in a network can give a latency reduction of up to 58.9%. Also, the altitude of the HAP directly affects the angle of reception which was found to improve the coverage
Meteorological satellites
An overview is presented of the meteorological satellite programs that have been evolving from 1958 to the present, and plans for the future meteorological and environmental satellite systems that are scheduled to be placed into service in the early 1980's are reviewed. The development of the TIROS family of weather satellites, including TIROS, ESSA, ITOS/NOAA, and the present TIROS-N (the third generation operational system) is summarized. The contribution of the Nimbus and ATS technology satellites to the development of the operational-orbiting and geostationary satellites is discussed. Included are descriptions of both the TIROS-N and the DMSP payloads currently under development to assure a continued and orderly growth of these systems into the 1980's
An implementation plan for priorities in solar-system space physics
The scientific objectives and implementation plans and priorities of the Space Science Board in areas of solar physics, heliospheric physics, magnetospheric physics, upper atmosphere physics, solar-terrestrial coupling, and comparative planetary studies are discussed and recommended programs are summarized. Accomplishments of Skylab, Solar Maximum Mission, Nimbus-7, and 11 other programs are highlighted. Detailed mission plans in areas of solar and heliospheric physics, plasma physics, and upper atmospheric physics are also described
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