Interpolation of ionospheric modalities using kriging, co-kriging and spatio-temporal kriging
Author
Khaf, Sadia
Advisor
Arıkan, Orhan
Date
2018-06Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
118
views
views
23
downloads
downloads
Metadata
Show full item recordAbstract
Long distance communication and navigation systems operating in the HF band
use interacting signals as they travel through the ionosphere. It is important
to accurately model ionospheric behavior to increase the performance of these
systems. Delays occurring in the signals depend on the refrectivity which is a
function of frequency of the signals, and the electron density on the signal path
at the time of propagation. Depending on the change in the solar activities, the
electron distribution in the ionosphere changes spatially and temporally. The
change in ionosphere can be tracked by various parameters and the space-time
distribution of these parameters. Total Electron Content (TEC), the total number
of electrons in a cylinder with one meter square cross-sectional area over a
ray path is used as an important descriptor for the ionosphere. It is possible to
generate TEC maps with high spatial resolution using the information obtained
by processing the GPS satellite signals by constantly operating reference stations
(CORS) GPS receivers. In particular, there are two other parameters that are
used in HF communication and direction nding applications: foF2, which is
the highest plasma frequency of foF2 layer, and hmF2, which is the height of
maximum ionization. Sensitive foF2 and hmF2 measurements can be made by
ionosonde systems. However, these systems are highly sparser than TEC measurements.
For this reason, the resolution of the foF2 and hmF2 maps is less than
the TEC maps. In this study, we propose a space-time mapping technique based
on Co-Kriging which is used in conjunction with TEC data, that is correlated
to these parameters, to increase the resolutions of foF2 and hmF2 maps. The
performance of the proposed technique is compared with the alternatives and the
increase in performance achieved is described statistically.