SEMINAR: Interpolation of Ionospheric Modalities using Kriging, Co-Kriging, and Spatiotemporal Kriging
By Sadia Khaf
M.S. in Electrical and Electronics Engineering
Prof. Dr. Orhan Arıkan
The seminar will be on Monday, June 4, 2018 at 10.00 @ EE-314
ABSTRACT
Long distance communication systems 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 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 is followed by various parameters and the space-time distribution of these parameters changes accordingly. Total Electron Content (TEC: the total number of electrons in a cylinder with one meter square cross-sectional area rising vertically from the ground surface) 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 certain precise GPS receivers. In particular, there are two other parameters that are used in HF communication and direction finding applications: foF2, which is the highest frequency broadcasted perpendicular to the earth by HF systems that can reflect back, and hmF2, which is the height of this frequency reflection. Sensitive foF2 and hmF2 measurements can be made by ionosonde systems. However, these systems are less frequent than TEC measurement stations. 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.