Fundamental analysis of the tomographic imaging system for reconstructing ionospheric distributions

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:6821085

Na, H R

Ionospheric tomography has generated great interest due to the possibility of two-dimensional imaging of electron density profiles. Traditional methods have, thus far, been capable of only one-dimensional imaging. Tomographic reconstructions are possible from existing one dimensional data and can be enhanced by knowledge gained through traditional imaging methods. In this thesis, a complete ionospheric imaging system is presented. The ionosphere is a plasma of ionized gas formed by ionization of the upper atmosphere by solar radiation and high-energy particles from the sun. Regions of irregular electron concentration exist within this layer of plasma, which interfere with the propagation of radio signals as they are reflected around the earth's surface by the ionosphere. Although there are well-accepted theories on the formation of the ionosphere, there are no corresponding theories for the formation of these irregularities. As a result, imaging the electron density is the best method of determining the location and nature of these irregularities. In this thesis, the ionospheric system was analyzed and modeled as a tomographic imaging system. The complete ionospheric imaging system was formulated in three segments: the ionospheric data acquisition system, the system model, and a reconstruction algorithm. The fundamental resolution limits of this system were then analyzed in several ways. The resolution of the imaging system based upon controllable parameters was examined followed by a quantitative measure of the complete imaging system's resolving capability. The effect of the various resolution degradation factors was then isolated and methods of compensation were investigated. Once the resolving capabilities of the system have been thoroughly determined, a variety of methods for enhancing the reconstruction algorithm will be developed. These methods will take advantage of existing knowledge of the ionosphere.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 6821085
• Resource Relation: Other Information: Ph.D. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPUTERIZED TOMOGRAPHY
TWO-DIMENSIONAL CALCULATIONS
IONOSPHERE
ELECTRON DENSITY
ALGORITHMS
DATA ACQUISITION
DATA PROCESSING
IMAGES
PLASMA
SPATIAL RESOLUTION
DIAGNOSTIC TECHNIQUES
EARTH ATMOSPHERE
MATHEMATICAL LOGIC
PLANETARY IONOSPHERES
PROCESSING
RESOLUTION
TOMOGRAPHY
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)