Author: Jules Aarons
Publisher:
ISBN:
Category : Ionosphere
Languages : en
Pages : 72
Book Description
In order to provide systems engineers with observations and analysis of the amplitude-fading of radio waves traversing the high latitude ionosphere, several different studies were performed. The concept was to develop descriptive and statistical models for the pattern of occurrence and amplitude of scintillations at high latitudes. Then, long terms observations from a limited number of sites could be linked to allow an assessment of the scintillation problem to communication, navigation, and detection systems in the VHF and UHF bands. This report discusses these studies in three chapters. In Chapter 1, general patterns of scintillation occurrence and intensity are presented in the descriptive model of the F-layer irregularities at high latitudes. This is followed in Chapter 2 by a graphical presentation of the data; that is, observations of the 136 MHz beacon of ATS-3. Chapter 3 organizes the observations into a useful format-the cumulative amplitude probability distribution function-for the engineer. A means of adjusting the observations for frequency dependence is provided.
High Latitude Models, Observations and Analysis of Ionospheric Scintillations
Author: Jules Aarons
Publisher:
ISBN:
Category : Ionosphere
Languages : en
Pages : 72
Book Description
In order to provide systems engineers with observations and analysis of the amplitude-fading of radio waves traversing the high latitude ionosphere, several different studies were performed. The concept was to develop descriptive and statistical models for the pattern of occurrence and amplitude of scintillations at high latitudes. Then, long terms observations from a limited number of sites could be linked to allow an assessment of the scintillation problem to communication, navigation, and detection systems in the VHF and UHF bands. This report discusses these studies in three chapters. In Chapter 1, general patterns of scintillation occurrence and intensity are presented in the descriptive model of the F-layer irregularities at high latitudes. This is followed in Chapter 2 by a graphical presentation of the data; that is, observations of the 136 MHz beacon of ATS-3. Chapter 3 organizes the observations into a useful format-the cumulative amplitude probability distribution function-for the engineer. A means of adjusting the observations for frequency dependence is provided.
Publisher:
ISBN:
Category : Ionosphere
Languages : en
Pages : 72
Book Description
In order to provide systems engineers with observations and analysis of the amplitude-fading of radio waves traversing the high latitude ionosphere, several different studies were performed. The concept was to develop descriptive and statistical models for the pattern of occurrence and amplitude of scintillations at high latitudes. Then, long terms observations from a limited number of sites could be linked to allow an assessment of the scintillation problem to communication, navigation, and detection systems in the VHF and UHF bands. This report discusses these studies in three chapters. In Chapter 1, general patterns of scintillation occurrence and intensity are presented in the descriptive model of the F-layer irregularities at high latitudes. This is followed in Chapter 2 by a graphical presentation of the data; that is, observations of the 136 MHz beacon of ATS-3. Chapter 3 organizes the observations into a useful format-the cumulative amplitude probability distribution function-for the engineer. A means of adjusting the observations for frequency dependence is provided.
Report on Research at AFCRL.
Author: Air Force Cambridge Research Laboratories (U.S.)
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 336
Book Description
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 336
Book Description
Report UAG.
Author:
Publisher:
ISBN:
Category : Atmosphere, Upper
Languages : en
Pages : 1258
Book Description
Publisher:
ISBN:
Category : Atmosphere, Upper
Languages : en
Pages : 1258
Book Description
An Empirical Model of Ionospheric Scintillation at High Latitudes
Author: Hichem Mizaoui
Publisher:
ISBN:
Category : GPS receivers
Languages : en
Pages : 0
Book Description
Trans-ionospheric radio signals experience both amplitude and phase variations as they propagate through a turbulent ionosphere, this phenomenon is known as scintillation. As a result of these fluctuations, GPS receivers lose track of signals and consequently induce positioning and navigational errors. Therefore, there is a need to study scintillation and their causes in order to not only resolve the navigational problem but in addition develop analytical and numerical radio propagation models. This thesis presents the work that has been done to develop an empirical model of ionospheric scintillation at high latitudes. In this study, GPS L1 signals were recorded and characterized using the Canadian High Arctic Ionospheric Network (CHAIN).We developed new indices to quantify scintillation and the chaoticity of the turbulent ionosphere. More particularly, we used the multi-fractal aspect of the scintillating GPS signal to compute the corresponding wavelet-based entropy and fractal dimension. These indices were used to construct scintillation maps in the geomagnetic domain. It has been found that the chaoticity of the scintillating signal exhibits a dependence on geomagnetic conditions and a seasonal cycle, suggesting the possibility to quantify the ionospheric turbulence using the proposed indices. In the second part of the thesis, a simulator of the trans-ionospheric channel was developed. The model takes into account the case of strong scintillation, where the amplitude fluctuations start to build up inside the ionospheric slab. The features of the power spectra of the observed scintillation events were reproduced: it has been found that the amplitude fluctuations are characterized by a power spectral density that obeys a power law with a break down at the Fresnel scale. The phase, on the other hand, does not exhibit a breakdown of the power law, which is in agreement with the observations.
Publisher:
ISBN:
Category : GPS receivers
Languages : en
Pages : 0
Book Description
Trans-ionospheric radio signals experience both amplitude and phase variations as they propagate through a turbulent ionosphere, this phenomenon is known as scintillation. As a result of these fluctuations, GPS receivers lose track of signals and consequently induce positioning and navigational errors. Therefore, there is a need to study scintillation and their causes in order to not only resolve the navigational problem but in addition develop analytical and numerical radio propagation models. This thesis presents the work that has been done to develop an empirical model of ionospheric scintillation at high latitudes. In this study, GPS L1 signals were recorded and characterized using the Canadian High Arctic Ionospheric Network (CHAIN).We developed new indices to quantify scintillation and the chaoticity of the turbulent ionosphere. More particularly, we used the multi-fractal aspect of the scintillating GPS signal to compute the corresponding wavelet-based entropy and fractal dimension. These indices were used to construct scintillation maps in the geomagnetic domain. It has been found that the chaoticity of the scintillating signal exhibits a dependence on geomagnetic conditions and a seasonal cycle, suggesting the possibility to quantify the ionospheric turbulence using the proposed indices. In the second part of the thesis, a simulator of the trans-ionospheric channel was developed. The model takes into account the case of strong scintillation, where the amplitude fluctuations start to build up inside the ionospheric slab. The features of the power spectra of the observed scintillation events were reproduced: it has been found that the amplitude fluctuations are characterized by a power spectral density that obeys a power law with a break down at the Fresnel scale. The phase, on the other hand, does not exhibit a breakdown of the power law, which is in agreement with the observations.
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836
Book Description
Global Morphology of Ionospheric Scintillations II
Author: Jules Aarons
Publisher:
ISBN:
Category : F region
Languages : en
Pages : 30
Book Description
Updating a review of the global morphology of ionospheric scintillations published in 1971, this study adds additional experimental studies on familiar topics to newer types of measurements of ionospheric irregularities, including in situ experiments and artificial heating of the F-layer.
Publisher:
ISBN:
Category : F region
Languages : en
Pages : 30
Book Description
Updating a review of the global morphology of ionospheric scintillations published in 1971, this study adds additional experimental studies on familiar topics to newer types of measurements of ionospheric irregularities, including in situ experiments and artificial heating of the F-layer.
Air Force Surveys in Geophysics
Author:
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 304
Book Description
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 304
Book Description
Space Physics and Aeronomy, Ionosphere Dynamics and Applications
Author: Chao Huang
Publisher: John Wiley & Sons
ISBN: 1119507553
Category : Science
Languages : en
Pages : 47
Book Description
A comprehensive review of global ionospheric research from the polar caps to equatorial regions It's more than a century since scientists first identified the ionosphere, the layer of the Earth’s upper atmosphere that is ionized by solar and cosmic radiation. Our understanding of this dynamic part of the near-Earth space environment has greatly advanced in recent years thanks to new observational technologies, improved numerical models, and powerful computing capabilities. Ionosphere Dynamics and Applications provides a comprehensive overview of historic developments, recent advances, and future directions in ionospheric research. Volume highlights include: Behavior of the ionosphere in different regions from the poles to the equator Distinct characteristics of the high-, mid-, and low-latitude ionosphere Observational results from ground- and space-based instruments Ionospheric impacts on radio signals and satellite operations How earthquakes and tsunamis on Earth cause disturbances in the ionosphere The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about the Space Physics and Aeronomy collection in this Q&A with the Editors in Chief
Publisher: John Wiley & Sons
ISBN: 1119507553
Category : Science
Languages : en
Pages : 47
Book Description
A comprehensive review of global ionospheric research from the polar caps to equatorial regions It's more than a century since scientists first identified the ionosphere, the layer of the Earth’s upper atmosphere that is ionized by solar and cosmic radiation. Our understanding of this dynamic part of the near-Earth space environment has greatly advanced in recent years thanks to new observational technologies, improved numerical models, and powerful computing capabilities. Ionosphere Dynamics and Applications provides a comprehensive overview of historic developments, recent advances, and future directions in ionospheric research. Volume highlights include: Behavior of the ionosphere in different regions from the poles to the equator Distinct characteristics of the high-, mid-, and low-latitude ionosphere Observational results from ground- and space-based instruments Ionospheric impacts on radio signals and satellite operations How earthquakes and tsunamis on Earth cause disturbances in the ionosphere The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about the Space Physics and Aeronomy collection in this Q&A with the Editors in Chief
Ionospheric Scintillations/TEC and In-situ Density Measurements at an Auroral Location in the European Sector
Author: Eileen MacKenzie
Publisher:
ISBN:
Category : Auroras
Languages : en
Pages : 52
Book Description
The orbiting HiLat satellite launched in 1983 offered an opportunity for studying ionospheric scintillation parameters in relation to in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This report discusses results of a morphological study based on observations of scintillations and total electron content (TEC) at the auroral oval station at Tromso, Norway, during the period Dec 1983 - Oct 1985. The geometrical enhancement of scintillations observed during alignment of the propagation with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/magnetic local time grid. Steepening of phase spectral slope in the geometrical enhancement region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variation of TEC determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to the in-situ density measurements at 830 km. The results are also used to illustrate the dependence of ionospheric structure parameters on short-term variability of solar activity during the sunspot minimum period. This study provides an insight into the nature of magnetospheric coupling with the ionosphere at high latitudes.
Publisher:
ISBN:
Category : Auroras
Languages : en
Pages : 52
Book Description
The orbiting HiLat satellite launched in 1983 offered an opportunity for studying ionospheric scintillation parameters in relation to in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This report discusses results of a morphological study based on observations of scintillations and total electron content (TEC) at the auroral oval station at Tromso, Norway, during the period Dec 1983 - Oct 1985. The geometrical enhancement of scintillations observed during alignment of the propagation with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/magnetic local time grid. Steepening of phase spectral slope in the geometrical enhancement region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variation of TEC determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to the in-situ density measurements at 830 km. The results are also used to illustrate the dependence of ionospheric structure parameters on short-term variability of solar activity during the sunspot minimum period. This study provides an insight into the nature of magnetospheric coupling with the ionosphere at high latitudes.
GPS for Geodesy
Author: Peter J.G. Teunissen
Publisher: Springer Science & Business Media
ISBN: 3642720110
Category : Science
Languages : en
Pages : 629
Book Description
An in-depth description of the theory and mathematical models behind the application of the global positioning system in geodesy and geodynamics. The contributions by leading experts in the field ensure a continuous flow of ideas and developments. The mathematical models for GPS measurements are developed in the first half of the book, and these are followed by GPS solutions for geodetic applications on local, regional and global scales.
Publisher: Springer Science & Business Media
ISBN: 3642720110
Category : Science
Languages : en
Pages : 629
Book Description
An in-depth description of the theory and mathematical models behind the application of the global positioning system in geodesy and geodynamics. The contributions by leading experts in the field ensure a continuous flow of ideas and developments. The mathematical models for GPS measurements are developed in the first half of the book, and these are followed by GPS solutions for geodetic applications on local, regional and global scales.