| 项目编号: | 1445468
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| 项目名称: | Collaborative Research: Cubesat--Ionospheric Scintillation Explorer (ISX) |
| 作者: | Hasan Bahcivan
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| 承担单位: | SRI International
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| 批准年: | 2014
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| 开始日期: | 2015-08-15
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| 结束日期: | 2018-07-31
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| 资助金额: | USD454219
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| 资助来源: | US-NSF
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| 项目类别: | Continuing grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
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| 英文关键词: | scintillation pattern
; project
; scintillation
; structure
; isx
; ionospheric scintillation
; flux tube
; trans-ionospheric radio signal
; scintillation-scale
; trans-ionospheric
; magnetic field
; scintillation effect
; scintillation-scale turbulent structure
; previous radio aurora explorer
; spacecraft cubesat mission
; ionospheric radio wave distortion
; ionospheric electron density
; nsf cubesat project
; ionospheric irregularity
; scintillation-scale ionospheric irregularity
; ionospheric density structure
|
| 英文摘要: | This project is to design, develop, construct, operate and analyze the results of a spacecraft CubeSat mission named "Ionospheric Scintillation eXplorer" (ISX). Ionospheric scintillation refers to random fluctuations in amplitude and phase of radio signals traversing a region of turbulence in the ionosphere. It impacts the power and phase of the radio signal and is caused by small-scale (kilometer to centimeters) structure in the ionospheric electron density along the signal path. Ionospheric scintillation affects trans-ionospheric radio signals up to a few GHz in frequency and, thus, can have detrimental impacts on satellite-based communication and navigation systems, such as GPS-based systems, and also on scientific instruments requiring observations of trans-ionospheric radio signals, e.g. for radio astronomy. The physics behind the generation of the plasma irregularity structures that cause scintillation is not fully understood, largely due to a lack of adequate observations. An obvious consequence of this is that neither does a reliable capability exist for the prediction or mitigation of the effects of scintillations on radio waves. ISX will generate an extensive dataset for applying diffraction radio imaging, which enables the prediction of scintillations at any frequency determined from the imaged structure, and potentially the mitigation of distorted signals by canceling phase fluctuations. Another broader impact of the proposed project is that it is a pilot effort to provide global, space-based monitoring of ionospheric radio wave distortion using signals of opportunity available worldwide. While a single spacecraft cannot provide real-time monitoring, it can show the way for a constellation of spacecraft to provide such a space weather service in the future. Scintillation effects occur predominantly in the equatorial region in ionospheric density structures termed Equatorial Spread F (ESF). The main goal of this project is to provide new observations on the structure of scintillation-scale ionospheric irregularities associated with ESF. Specifically, ISX will simultaneously record scintillation patterns of multiple ground-based digital television (DTV) carrier signals. Scintillation patterns for a unique set of experimental geometries will be compared to determine how far along the magnetic field the turbulence maps, which is crucial observational data on the three-dimensional electrodynamics of these sub-km structures.
During the lifecycle of the project, it will provide extensive student training opportunities, including student involvement through Cal Poly spacecraft design classes and funded graduate students. Each year, 20-40 students will be involved in the design, fabrication, and flight of this mission. Cal Poly has flown many student satellite missions; the proposed effort will leverage the heritage and experience from all of these.
This project addresses the science question: To what distance along a flux tube does an irregularity of certain transverse-scale extend? It has been difficult to measure the magnetic field-alignment of scintillation-scale turbulent structures because of the difficulty of sampling a flux tube at multiple locations within a short time. This measurement is now possible due to the worldwide transition to DTV, which presents unique signals of opportunity for remote sensing of ionospheric irregularities from numerous vantage points. DTV spectra, in various formats, contain phase-stable, narrowband pilot carrier components that are transmitted simultaneously. A 4-channel radar receiver will simultaneously record up to 4 spatially separated transmissions from the ground. For most experimental geometries, the corresponding transmitter-satellite lines-of-sight will cross the same magnetic flux tube within 1-10 s, a reasonably short time to assume "frozen" irregularities. Correlations of amplitude and phase scintillation patterns corresponding to multiple points on the same flux tube will be a measure of the spatial extent of the structures along the magnetic field. A subset of geometries where two or more transmitters are aligned with the orbital path will be used to infer the temporal development of the structures. The radio receiver is based on the instrument developed and successfully demonstrated on the previous Radio Aurora eXplorer (RAX) NSF CubeSat project. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/93649
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Hasan Bahcivan. Collaborative Research: Cubesat--Ionospheric Scintillation Explorer (ISX). 2014-01-01.
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